Installation Guide and Users Manual

Transcription

1 DSATools TM Dynamic Security Assessment Software VSAT Voltage Security Assessment Tool VERSION 6.0 Installation Guide and Users Manual A product of Powertech Labs Inc th Avenue Tel: (604) Surrey, British Columbia Fax (604) Canada V3W 7R7

2 DISCLAIMER OF WARRANTIES AND LIMITATION OF LIABILITIES THIS SOFTWARE AND ITS DOCUMENTATION WERE PREPARED BY POWERTECH LABS, INC. (PLI). NEITHER PLI, ANY COSPONSOR, NOR ANY PERSON ACTING ON BEHALF OF ANY OF THEM: (A) MAKES ANY WARRANTY OR REPRESENTATION WHATSOEVER, EXPRESS OR IMPLIED, (I) WITH RESPECT TO THE USE OF ANY INFORMATION, APPARATUS, METHOD, PROCESS, OR SIMILAR ITEM DISCLOSED IN THIS REPORT, INCLUDING MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE, OR (II) THAT SUCH USE DOES NOT INFRINGE ON OR INTERFERE WITH PRIVATELY OWNED RIGHTS, INCLUDING ANY PARTY'S INTELLECTUAL PROPERTY, OR (III) THAT THIS REPORT IS SUITABLE TO ANY PARTICULAR USER'S CIRCUMSTANCE; OR (B) ASSUMES RESPONSIBILITY FOR ANY DAMAGES OR OTHER LIABILITY WHATSOEVER (INCLUDING ANY CONSEQUENTIAL DAMAGES, EVEN IF PLI OR ANY PLI REPRESENTATIVE HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES) RESULTING FROM YOUR SELECTION OR USE OF THIS REPORT OR ANY INFORMATION, APPARATUS, METHOD, PROCESS, OR SIMILAR ITEM DISCLOSED IN THIS REPORT. VSAT program and its documentation are confidential property of BC Hydro and Powertech Labs Inc. This Program is protected under the copyright laws and by application of international treaties. All Rights Reserved under the Copyright Laws. Except as expressly provided by the terms and conditions set forth in the License, the LICENSEE shall not: (a) distribute or disclose the Program, Documentation or Derivative Work thereof to others; or (b) disclose the Proprietary Information associated with or embodied in the Program and Documentation in any form whatsoever; without prior written consent of Powertech Labs Inc. The LICENSEE shall not use the program except as expressly provided by the conditions of LICENSE TYPE in the License. Copyright British Columbia Hydro And Power Authority 1999:2006 Powertech Labs Inc. i

3 CONTENTS Page 1 PROGRAM INSTALLATION AND TESTING Minimum System Requirements Installing VSAT Included Files Running VSAT Test Cases OVERVIEW VSAT Description Security Assessment Module Secure Range Secure Region Modal Analysis VQ Curve Computation Contingency Screening Module Fast Time Domain Module Remedial Action Module Distributed Processing Scenarios and Data Files The Scenario Concept Data Files Computation Process Contingency Screening Process VSAT Structure VSAT Main Window SETTING UP SCENARIOS Preparing the Scenarios Manually Preparing the Data Files Preparing the Scenario File Preparing the Master Scenario File Preparing the Scenarios through VSAT GUI Creating a New Scenario Adding Existing Scenario Files Modifying Scenarios and Data Files Removing Scenarios Viewing Powerflow Data Archiving Scenarios Creating and Saving a Master Scenario (or Case) FILE Adding Scenarios Using A Master Scenario File Archiving All Scenarios Exiting VSAT Powerflow Data and Conversion to PFB Data Views General Features of Data Views Parameter Data View Transfer Data View Contingency Script View Contingency Data View Generator Capability Data View Load Conversion Data View Other Data Views...38 Powertech Labs Inc. ii

4 4 RUNNING VSAT Starting and Controlling the Servers Converting Powerflow Data Screening Contingencies Enabling/Disabling Scenarios Running the Security Assessment Viewing the Limits and Violations Viewing the Messages Live Plot of Monitored Variables Viewing and Plotting the Results FTD FTD Data Requirement Running FTD REMEDIAL ACTION RA Data Requirement Running RA DISTRIBUTED PROCESSING SETUP Stand-alone Network Connection Existing Network Connection Configuring Networked Computers Configuring Stand-alone Computer Setting up Multiple Servers on a Single PC OUTPUT FILES INPUT DATA FILE FORMATS General Rules Data File Structure Data Records Name Option Include and Exclude Records Powerflow File PFB (or PSF) File Parameter File Transfer File Criteria File Margin File Monitored Variable File Contingency Script File Contingency File Interface and Circuit File Generator Capability File Governor Response File AGC Action File Load Conversion File Branch Rating File Contingency Screening Parameter File Modal Analysis Parameter File VQ Curve File Powertech Labs Inc. iii

5 9.20 Control Mode File Dynamic Data File FTD Parameter File FTD Monitor File FTD Switching File Remedial Control File Sensitivity Parameter File Powertech Labs Inc. iv

6 1 Program Installation and Testing This chapter describes program installation and testing on Windows 2000, XP and NT systems. You may have received either VSAT Stand-alone or VSAT Client-Server version, with either Single-User or Network Security Key(s). The client-server version requires both the VSAT client and server to be installed (you may install the client and servers on different computers). You must install the driver for the single-user security key, and attach one key to the parallel port of each computer running VSAT stand-alone or VSAT client (not VSAT server). On the other hand, the network key can be attached to any computer on the network and you must install the Sentinel server as well as the driver on that computer. 1.1 Minimum System Requirements The minimum hardware and software requirements for the Windows version are: 1. PC Pentium Mb of free hard disk space Mb of RAM 4. VGA card 5. Windows 2000, XP or NT version 3.5 or higher 6. Acrobat Reader 1 7 for viewing the on-line manual 1.2 Installing VSAT Running the installation program provided on the VSAT CD creates the necessary folders and files on your computer. To install the software: 1. Place the CD in your CD drive. After a few seconds, the Powertech Software Installation Guide window will appear on your screen. In this case go to step 3, otherwise go to step To start the installation and open the Powertech Software Installation Guide window on your screen, from the Start menu of your computer select Run and type: X:\start.exe where X is the drive in which the VSAT CD is inserted (e.g. D:\start.exe) 3. Click on Install DSA Software (or run the setup.exe program from the CD) to install VSAT. When the DSA installer window appears, follow the steps as shown on your screen to complete the installation. The installation steps are: 3.1 Display of program information and welcome message. 3.2 Display of License Agreement: You must accept the terms of license to complete the installation. 3.3 Display of installation information. 3.4 Selection of destination folder: By default, the installation program creates a directory named VSAT (or DSATools_n\VSAT if the CD also contains other PLI's DSATools TM ) on the destination drive (C) 1 Adobe and Acrobat are trademarks of Adobe Systems Incorporated Powertech Labs Inc. Page 1

7 to copy the files. You may change this default destination to other directories/drives. However, for the VSAT shortcut to work properly, do not choose a destination name that has a blank, such as "C:\Program Files\VSAT". 3.5 Selection of setup type: You may select to install some or all of the VSAT components on each computer. The Typical setup (default) installs the VSAT stand-alone, client, server and all related components (and other components of DSATools TM if provided). The Minimal setup installs the VSAT stand-alone and related components. The Custom setup allows you to choose which component is to be installed. In the Custom setup window, click on the + beside VSAT to expand the list of components and click on the arrow beside each component to make your selection from the drop-down list. You need to install, as minimum, the VSAT stand-alone, or VSAT client and server on one computer. The VSAT server can be installed on a different computer, and you may install it on several computers if you want to use them simultaneously to run VSAT cases in parallel. User interface is with the VSAT stand-alone or client. The servers only interact with the client and can not be used independently. See Chapter 7 on how to configure your system for parallel (distributed) processing. 3.6 After copying the files, the installation creates a folder named VSAT (or DSA_PLI with subfolders VSAT, TSAT and SSAT) under Start Programs and adds shortcuts to the executables in this folder. 3.7 The installation program will set the path for running VSAT by adding C:\VSAT (assuming the destination directory is VSAT on drive C) to the PATH in AUTOEXEC.BAT file. To make this path effective, the computer must be rebooted. 4. Click on Install Sentinel Driver/Server (or run the Sentinel\setup.exe program from the CD) to install the driver and/or server for the security key. When the Sentinel Combo installer window appears, follow the steps as indicated on the screen. You may choose the Custom setup type to select the parallel driver or USB driver (depending on the type of key you have received with the software), server, and/or monitoring tool to be installed. You need to install the driver for the stand-alone security key, or the driver and server for the network security key, on the computers where the key(s) will be attached. For more information, refer to the Readme file or the following files on the CD: Sentinel\Readme.pdf Sentinel\Documentation\SentinelSP Sys Admin Guide.pdf You may need administrative privilege on Windows NT to install the driver/server. To complete the driver/server installation, the computer must be rebooted. On Windows NT If VSAT can not open temporary files on your system, you need to set the TMPDIR environment variable to a directory where you have write access. For this, from the Start Settings open the Control Panel and from there open the System window. Under the Environment tab, type TMPDIR in the Variable box and C:\Winnt\Temp (or some other directory where you can create files) in the Value box and click on OK button. 1.3 Included Files The Typical installation creates the following subdirectories and files under the program directory (e.g. VSAT): Powertech Labs Inc. Page 2

8 Bin\ subdirectory of executable files including: VSAT.exe VSATClient.exe VSATServer.exe VSAT_batch.exe DSAOA.exe CNVPSF.exe *.dll *.cnt, *.hlp Data\ vsat.vsa ftd.vsa *.snr t.*, case11.* ref-output\ *.* Server-Data\ Server-Output\ Manual\ VSAT-manual.pdf FTD-model-manual.pdf DSAOA- manual.pdf Readme.pdf VSAT s stand-alone executable VSAT s client executable (optional) VSAT s server executable (required by VSAT client) VSAT s batch (non-gui) executable (optional) DSA-OA executable Batch (non-gui) Powerflow data format conversion program (optional) DLLs for powerflow conversion and other module Help files subdirectory of test cases including: Master scenario file with three scenarios Master scenario file with one scenario for FTD scenario files of test cases data files of test cases (powerflow file, transfer file, etc.) reference output files of test cases subdirectory for VSATServer s input data files (will be empty) subdirectory for VSATServer s output files (will be initially empty) subdirectory of VSAT documents including: VSAT manual in PDF format FTD model manual in PDF format DSA-OA manual in PDF format information about VSAT and its installation The Minimal installation will create Bin\VSAS.exe and Bin\DSAOA.exe (and related *.dll, and their shortcut under Start Programs VSAT), Data and Manual subdirectories. The Custom installation of VSAT server component alone will create Bin\VSAServer.exe (and its shortcut under Start Programs VSAT) and Server-Data and Server-Output subdirectories. 1.4 Running VSAT Test Cases To run the test cases: 1. To use VSAT Client-Server, start VSAT Server from the Start menu Start Programs DSATools n VSAT n.m VSATServer (where n and n.m are version number of DSATools and VSAT release). This starts the server in Server-Output directory and a window will open showing the server status (see Section 4.1 for details). If you have installed the server on several computers, you may start each server in the same way. Make sure you use the Start menu shortcut and not click on the VSAServer.exe itself to start it, so that the server starts with correct parameters and working directory. 2. Start VSAT Client (to use with multiple servers) or VSAT stand-alone from the Start menu Start Programs DSATools n VSAT n.m VSATClient or Start Programs DSATools n VSAT n.m VSAT. This opens the VSAT main window and loads in the vsat.vsa master scenario file in Data subdirectory. If this file is not loaded, under File menu select Open and in the Open window find vsat.vsa in the Data subdirectory of VSAT and double click on it. See Section for details Powertech Labs Inc. Page 3

9 3. If you started VSAT Client, under View menu in the VSAT main window (shown below), select Servers. In the Server List window, you should see the running servers as Enabled and Free. If not, you need to add the servers as described in Section Under Analysis menu in the VSAT main window, select Run Security Assessment (or click on the Run button on the tool bar). The scenarios will run and when the run is completed, the VSAT main window shows Finished in the Status column and displays the transfer limits. Under the Range Scenarios tab in the lower part of the VSAT window, the bar charts and limit table of scenarios 1, 2 and 4 are displayed as shown below: Figure 1.1 VSAT main window after completed run 5. Click on the sxy tab to see the Secure Region and limit table of scenario 3. Click on a point on the green area boundary and the corresponding row in the limit table will be highlighted. Figure 1.2 Plot and table of security limits of S35-XY scenario Powertech Labs Inc. Page 4

10 6. The following output files will be created by this run: sx.*, sx-*.* sy.*, sy-*.* sxy.*, sxy-*.* sz.*, sz-*.* outputs of scenario 1 (t-x.snr) outputs of scenario 2 (t-y.snr) outputs of scenario 3 (t-xy.snr) outputs of scenario 4 (t-z.snr) You may compare these files with corresponding s*.* files in the Data\Ref-output subdirectory of VSAT to ensure the program has produced correct and complete results. 7. To run the Remedial Action Module, in the VSAT main window select the Analysis Remedial Action menu. This opens the RA window In the Select Scenario pull-down list, select scenario 1 - sx In the Select the Operating Point box type Pull down the Run menu and select Sensitivity method. RA runs and the results are displayed in the Result box of the RA window as shown in the above figure. Figure 1.3 Remedial Action window 8. To run the FTD Module, in the VSAT main window: 8.1. Select the File Open menu and in the Open window that appears, find and double click on the ftd.vsa master scenario file in the VSAT data directory to open it Select the Analysis Fast Time Domain menu. The FTD window appears In the FTD window, the Select Scenario pull-down list shows scenario 1 - C In the Select the Operating Point box type 6677 and leave the after Stress box blank (unchecked) Under the Contingency tab, the Select Contingency pull-dowm list shows the first contingency (L67) and the File Contents box shows the translation of this contingency into FTD Switching file. On the second line in this box, change the SIMULATION duration from to seconds. Save this change in the FTD_untitled.swt file by selecting the File Save menu. Powertech Labs Inc. Page 5

11 Figure 1.4 FTD window 8.6. Pull down the Run menu and select Fast Time Domain analysis. FTD runs and under the Results tab, the graph shows two monitored bus voltages and the Details box shows the voltage drop violation, as in the following figure. Figure 1.5 FTD results Powertech Labs Inc. Page 6

12 2 Overview 2.1 VSAT Description VSAT is a state-of-the-art tool for the assessment of power system voltage security. VSAT includes a number of specialized analytical techniques designed to permit the efficient analysis of large complex power systems. With VSAT, the user can specify a large number of scenarios which will be automatically analyzed to provide such information as the critical contingencies and voltage security limits. The computations performed by VSAT are based on powerflow methods which, through many years of research and industry experience, have proven to produce practical and accurate results. However, to obtain more detailed analysis of particular cases, VSAT is equipped with the Fast Time Domain (FTD) simulation module which can be used to quickly compute the time trajectory of the system following disturbances. In special situations in which full time-domain simulations are required, such as when rotor angle stability may be a concern, the companion Transient Security Assessment Tool (TSAT) can be used. Together, VSAT and TSAT provide a comprehensive assessment of all important aspects of system security. VSAT has been designed for use off-line (planning and operational planning studies) as well as for use on-line (connected directly to an energy management system and enabled to automatically assess voltage security using live system snapshots). This document describes the general features and use of the program, but is focused on the off-line application only. 2.2 Security Assessment Module The Security Assessment Module determines: 1. Voltage security of a given base operating point 2. Security limits of one and two-dimensional power transfers (Range or Region of secure operation of the system). The base or any other operating point (increased power transfer) is deemed Voltage Secure if it meets the specified voltage security criteria. The security criteria supported in this version of VSAT can be any combination of the following: (a) the system remains Voltage Stable (powerflow solution exists) in pre-contingency and all postcontingency conditions (b) the system has the minimum specified margin to instability. This means the system remains Voltage Stable if it is stressed by the specified MW/MVAr amount of margin requirement (c) pre and post-contingency voltages are within specified limits (d) pre and post-contingency VAr reserves of selected sources are larger than specified limits (e) pre and post-contingency loading of lines and transformers are below the specified thermal ratings Secure Range The Secure Range (one-dimensional transfer limit) indicates how far the power transfer can be increased in a specific direction before violating the voltage security criteria. The transfer increase is specified as any combination of load and generation changes. For example, suppose there are two generation areas, G1 and G2, and a load area, L1, in a system (Figure 2.1). Powertech Labs Inc. Page 7

13 If the load is increasing, the operator may wish to know how much load increase can be supplied from G1 securely (i.e., without violating the voltage security criteria). In this case the Transfer is defined as G1 increase along with L1 increase. G1 is called the source and L1 is called the sink of this transfer. L1 G1 G2 Similarly, the secure range may be computed for the transfer of power from G2 to L1. Another transfer direction can be 60% increase in G1 and 40% increase in G2 along with L1 increase. The secure range of each transfer is displayed in a bar chart as in Figure 2.2. These graphs show that, for example, G1 can supply 800 MW additional load (with G2 remaining constant), G2 can supply 600 MW additional load (with G1 constant) and G1 and G2 together (with 60/40 share) can supply 700 MW additional load. Figure 2.1 Schematic System G1 G Secure Region The Secure Region indicates how far the system can be moved from the current operating point in any direction consisting of three independent sources or sinks (called two-dimensional transfer). For the above example, these can be G1, G2 and L1. In this case the secure region is displayed as in Figure 2.3. The boundary of the secure region is reached when a critical contingency causes the violation of one or more of voltage security criteria. G1 60% + G2 40% Figure 2.2 Bar charts of Secure Ranges G Modal Analysis When the voltage stability limit (unsolved powerflow) is found, the location of instability (the critical region of the system) is best identified by Modal Analysis (Eigen analysis of the jacobian matrix) at the stability limit point. The critical "Mode" computed at this point and the relative participation of buses in that mode show where in the system the instability occurs. The user can request Modal Analysis at this point or at any specified transfer level and contingency G Figure 2.3 Display of Secure Region VQ Curve Computation VQ curve computation is one of the earlier methods of voltage stability analysis. In addition to showing the sensitivity of the bus voltage to reactive power injection (or reactive load) at that bus, the curve shows the reactive power margin at that bus, which is how much the system can be stressed by reactive load increase at that one bus before it becomes unstable. Powertech Labs Inc. Page 8

14 The computation of VQ curves is very time consuming and is not a very good method for voltage stability analysis. PV curve (transfer increase) computation and Modal Analysis are much more useful for determining the stability margin of the system (with respect to realistic stresses, not an artificial reactive stress at one bus alone) and identifying the weak buses and voltage collapse regions for each contingency. 2.3 Contingency Screening Module The Contingency Screening Module screens all the specified contingencies to find the most severe ones. The specified contingencies may include all possible single element outages, double outages (of two parallel lines), or any other contingencies provided in a file. The module analyzes all these contingencies to find those with the smallest Voltage Stability (VS) margin. The VS margin of each contingency is the difference between the precontingency transfer at the initial operating point (Po) and the last point where the post-contingency solution exists (Pn). The number of most severe contingencies to be identified by the Contingency Screening Module is specified by the user. The user may provide an exhaustive list of all potential contingencies (the Full List ) and designate a number of contingencies as Must-Run (do not screen) or Don t-run (do not analyze). The program will then include the Must-Run contingencies and exclude the Don t-run contingencies from the selected contingencies (regardless of their severity). 2.4 Fast Time Domain Module In general, voltage stability limits can be satisfactorily computed using powerflow based steady-state methods. In fact, to handle large numbers of contingencies and transactions, steady-state methods remain the most practical. However, it is well recognized that the chronology of control actions can sometimes have an influence on the stability limits. Therefore it is desirable to have a method available which can consider the timing of switching and control actions and can be used to verify the limits found using steady-state methods. Full time-domain simulation using numerical integration of differential equations can provide the most accurate time response of a system subjected to a disturbance, but for voltage stability simulations which may extend into hundreds of seconds of real time, these types of simulations are too time consuming for on-line use. To address this need, a special method referred to as Fast Time Domain (FTD) Simulation was developed which is up to 1000 times faster than full time domain simulation and still can capture the effects of the controls which are important to voltage stability. The method focuses on the evolution of the system operating condition as driven by the following slow dynamics, Change in load Transformer under-load tap changer (ULTC) operation Generator field current limiters Automatic generation control The dynamics of other devices are assumed to be so fast that their effects are adequately captured by solving postcontingency steady-state equations for each device. The devices whose dynamics are neglected include Electromechanical transient of synchronous machines Exciters, stabilizers, and governors Induction motors HVDC links SVCs and other FACTS devices Fast Time-Domain Simulation Detailed Simulation Figure 2.4 Comparison of FTD with full time domain simulation Powertech Labs Inc. Page 9

15 The method represents the power system using a set of non-linear algebraic equations which include variables associated with the slow control devices listed above. As time progresses, the set of equations is solved each time the slow device variables change. In this fashion, the trajectory of the system through time is captured through a series of algebraic solutions which track the operation of slow control devices. The result is a very fast time response which can faithfully track the response obtained using full time domain simulation. Figure 2.4 shows such an example and it can be seen that although the fast dynamics are not captured in the FTD response, the FTD solution does capture slow dynamics very well and therefore is very useful for voltage stability assessment. FTD feature of VSAT allows the user to run the FTD simulation for a selected contingency at a selected operating point (with or without the specified stability margin) to find out whether the system remains voltage stable under that contingency. This can then be compared with the steady-state solution to determine if the chronology of the slow dynamics has had a significant impact on the solution. 2.5 Remedial Action Module When an operating point is found to be insecure, the user may wish to know what is the best action to make that operating point voltage secure. The Remedial Action (RA) module finds the answer among the user-specified list of available controls, such as generator and SVC voltage control, capacitor and reactor switching, ULTC tap adjustment and load shedding. RA first attempts to find the best Preventive control. These control actions would be taken before any contingency happens. If the identified preventive control is not sufficient to make the operating point secure for all contingencies, RA finds the necessary Corrective controls for each critical contingency. These controls (such as capacitor switching and load shedding) would be taken after the contingency happens to keep the system secure. The Sensitivity method of RA, finds the best control based on the sensitivity of the security violation to the controls. The process in general terms is the following: Preventive control: If the operating point itself is unstable (powerflow does not solve), find the best controls to make it stable. Find the best controls to remove voltage limit violations (pre- or post-contingency) Find the best controls to remove stability margin violations (pre- or post-contingency). Each control is checked to see if it causes voltage limit violation. If it does, it will be rejected and RA will search for another control. Find the best controls to remove VAr reserve violations (pre- or post-contingency). Each control is checked to see if it causes voltage limit or stability margin violation. If it does, it will be rejected and RA will search for another control. Corrective control: If the identified preventive controls are not sufficient to remove all violations, examine each contingency individually and find the best controls to remove its violations, similar to the preventive control process above. 2.6 Distributed Processing To be able to quickly analyze very large system models, large number of scenarios, and/or contingencies, VSAT has a distributed processing (client/server) version, as well as a stand-alone version. In the distributed processing version, one machine (which must be a PC) is used as client and several machines (not necessarily PCs) on the network are used as servers. Powertech Labs Inc. Page 10

16 The VSAT client automatically detects available servers running on the network and distributes the computation tasks to those servers. There is no limit on the number of servers used, and the computation speed increases almost linearly with the number of servers (depending on the relative power of the servers and required computations). The required setup for distributed processing is described in Chapter 7. Powertech Labs Inc. Page 11

17 2.7 Scenarios and Data Files This section describes the basic input and output file structures of VSAT and outlines the Scenario concept. Input data and general solution and control parameters required by VSAT are provided through Data Files. Collection of data files for computing one scenario (e.g., one transfer limit computation) is specified in a Scenario File (described below) and collection of Scenario Files for one VSAT run is specified in a Master Scenario File. VSAT displays the results of the simulations in tables and graphs. In addition, a number of Output Files are created which can be used to further analyze the results The Scenario Concept VSAT runs consist of the analysis of user specified scenarios which define the system conditions and types of analysis to be performed. A scenario includes the following type of information: A solved powerflow representing the base case conditions. Specification of the contingencies to be analyzed. Defined security criteria in terms of allowable voltage range, maximum allowable voltage declines, minimum allowable reactive reserves, and minimum allowable margin to voltage instability. Specification of one transfer (which defines how load and generation are to be changed), if a transfer limit computation is requested. Variables to be monitored during analysis. Computation solution parameters and other data as needed (such as governor response, AGC, etc). Available Controls and parameters for Remedial Action computation, if requested. Dynamic data and parameters for Fast Time Domain simulation, if requested. The above information is provided by the user in a set of data files, e.g., powerflow file, transfer file, etc. The names of the data files for each scenario are specified in the Scenario File. The user may setup any number of Scenarios and specify a collection of scenarios in a Master Scenario File. VSAT can analyze all scenarios of a Master Scenario File (also referred to as a VSAT case ) automatically in one execution cycle. Scenarios may share data files, for example, two scenarios could use the same base case powerflow, but examine different sets of contingencies or transfers. Scenario Files and Master Scenario Files can be set up through the VSAT GUI or separately by using any text file editor Data Files Data files for each scenario, depending on the type of analysis to be run, may include the following: Powertech Labs Inc. Page 12

18 Primary Data Files Base Powerflow File: Contains the base case powerflow data in PFB format. Data in other formats (IEEE, PTI, PECO, BPA, EPRI, PSF ASCII) must be converted into PFB format as described in Sections and 3.3. Parameter File: Contains parameters that specify program control actions, solution parameters, and output options. Transfer File: Contains specification of Transfer in terms of load and generation increase/decrease. Criteria File: Contains the voltage and reactive reserve criteria. Margin File: Contains the specification of the margin that is part of the voltage stability criteria. Full-Set Contingency File: Contains the full list of contingencies to be passed to contingency screening. (Screened) Contingency File: Contains the list of contingencies to be used in the security computation. If contingency screening is to be performed on the Full-Set Contingency list, this file will contain the list of contingencies identified by the screening. If contingency screening is not to be performed, this file contains a list of contingencies provided by the user. Contingency Screening Parameter File: Contains parameters for screening the contingencies. Monitor File: Contains the specification of the parameters to be monitored during the transfer limit computation. Interface Description File: Contains description of interfaces to be monitored. Secondary Data Files Contingency Script File: Contains the script (description) of contingency groups. Actual contingencies can be created from this script. Generator Capability File: Contains parameters for computing generator VAR limits based on field and armature current limits. Governor Response File: Contains governor data used in computing MW generations according to governor responses. AGC Action File: Contains AGC data used in computing MW generations according to AGC action. Load Conversion File: Contains description of voltage dependent load models to be used. Branch Rating File: Contains ratings of specified lines and transformers to be used in limit checking. Modal Analysis Parameter File: Contains parameters for Modal Analysis of unstable cases. VQ Curve File: Contains data (bus number, etc.) for computation of VQ curves. Control Mode File: Contains mode (locked, manual, etc.) of control devices (tap changers, etc.). Powertech Labs Inc. Page 13

19 Fast Time Domain Data Files Dynamic Data File: Contains generator, ULTC, OEL, etc. and their associated control parameters for the time domain simulation. Fast Time Domain Parameter File: Contains parameters for the time domain simulation. Fast Time Domain Monitor File: Contains the specification of the parameters to be monitored for the time domain simulation program. Remedial Action Data Files Remedial Action Control File: Contains information pertaining to the availability and priority of the voltage control devices such as shunts, generator scheduled voltage, etc. for the remedial action module. Remedial Action Sensitivity Method Parameter File: Contains parameters for the Remedial Action computation using the sensitivity method. These data files, with the exception of the powerflow file, are ASCII text files and can be set up through the VSAT GUI or separately by using any text file editor. The relationships of the input files used by VSAT are shown in Figure 2.5. Figure 2.6 shows the VSAT output files. The use of these files and their formats and contents, are described in various parts of this manual. The data files and scenario files of test cases are installed in the Data subdirectory of VSAT. You may inspect the contents of these files and use them as examples to set up your own data files. Powertech Labs Inc. Page 14

20 Master Scenario Files - Contain Lists of Scenario Files Scenario Files - Contain Lists of Data Files Data Files - Contain System and Control Data MASTER MASTER SCENARIO SCENARIO FILE 1 (.VSA) FILE 1 (.VSA) Scenario File 1 Scenario Scenario File File 1 5 Scenario File 5 MASTER MASTER SCENARIO SCENARIO FILE 2 FILE 2 Scenario File 2 Scenario Scenario File File 2 5 Scenario Scenario File File 5 3 Scenario Scenario File File 3 4 Scenario File 4 MASTER MASTER SCENARIO SCENARIO FILE N FILE N Scenario File 4 Scenario Scenario File File 4 6 Scenario Scenario File File 6 8 Scenario Scenario File File 8 9 Scenario File 9 SCENARIO SCENARIO FILE 1 (.SNR) FILE 1 (.SNR) Powerflow File A Powerflow Parameter File File A C Parameter Transfer File File C B Transfer File B Other Data Files Other Data Files SCENARIO SCENARIO FILE 2 FILE 2 Powerflow File D Powerflow Parameter File File D C Parameter Transfer File File C A Transfer File A Other Data Files Other Data Files SCENARIO SCENARIO FILE 3 FILE 3 Powerflow File D Powerflow Parameter File File D B Parameter Transfer File File B A Transfer File A Other Data Files Other Data Files Primary Data Files Powerflow Files (.PSF) Parameter Files (.PRM) Transfer Files (.TRF) Criteria Files (.CRT) Margin Files (.MRG) Full-Set Contingency Files (.CTF) (Screened) Contingency Files (.CTG) Contg. Screen. Parameter Files (.PCA) Monitored Variable Files (.MON) Interface and Circuit Files (.ITF) Secondary Data Files Contingency Script Files (.CTS) Generator Capability Files (.GCC) Governor Response Files (.GVR) AGC Action Files (.AGC) Load Conversion Files (.CLD) Branch Rating Files (.RAT) Modal Analysis Parameter Files (.MDP) VQ Curve Files (.VQC) Remedial Action Data Files Remedial Control Files (.RMC) Sensitivity Parameter Files (.SPR) Fast Time Domain Data Files Dynamic Data Files (.DYN) FTD Parameter Files (.FPR) INPUT FTD Monitor Files (.FMN) V S A T Figure 2.5 VSAT input files Powertech Labs Inc. Page 15

21 V S A T OUTPUT Main Output Main Output Report Report Scenario-id.prg Scenario-id.prg Contingency Contingency Screening Screening Report Report Scenario-id.cao Scenario-id.cao Remedial Action Remedial Action Main Output Main Output Scenario-id.ras Scenario-id.ras FTD Progress FTD Progress Report Report Scenario-id.ftd Scenario-id.ftd Monitored Monitored Variable Tables Variable Tables Scenario-id.pvt Scenario-id.pvt Remedial Action Remedial Action Detail Control Detail Control Report Report Scenario-id-ras.dtc Scenario-id-ras.dtc FTD Binary FTD Binary Results Results Scenario-id.bin Scenario-id.bin PV Curve PV Curve Output Output Scenario-id.pvp Scenario-id.pvp VQ Curve VQ Curve Output Output Scenario-id.vqp Scenario-id.vqp Remedial Action Remedial Action Summary Summary Report Report Scenario-id-ras.rpt Scenario-id-ras.rpt User Requested User Requested Reports Reports Scenario-id- Scenario-idxxx.rpxxx.rpt Security Security Limit Limit Scenario-id.lmt Scenario-id.lmt Figure 2.6 VSAT output files Powertech Labs Inc. Page 16

22 2.8 Computation Process This section describes the overall process of analyzing the security of each Scenario. Step 1: Step 2: The Scenario File and subsequently all related data files specified in the scenario file are read in. Multiple Scenario Files can be read in at one time by specifying a Master Scenario File. If the powerflow data is not in PFB (or PSF) format, it must be converted to PFB before any computation (manually or through the Auto feature). The contingency list in the Full-Set Contingency File is created from the Contingency Script File, or prepared manually, and then screened to identify the critical contingencies for each scenario. This process, if needed, must be initiated manually (it can also be triggered automatically by the Auto feature for each analysis cycle). The number of contingencies to be selected and other parameters used for screening are provided in the Contingency Screening Parameter File. The results of the screening (the critical contingencies) are written to the (Screened) Contingency File for use in the Security Assessment, and displayed in the Contingency Screening window. See the next section for details of screening process. This step can be bypassed if the user has provided all the contingencies (prepared manually or created from the Contingency Script file) for the security assessment step and does not wish to shorten the contingency list by screening. Step 3: The Security Assessment is performed for the base point (current operating point) provided in the Powerflow File. The Parameter File is used to specify the computation options, control options and parameters for the powerflow solution, and the level of output reporting. Security assessment solves the powerflow for the base case (pre-contingency) and for each of the contingencies in the Contingency File. If for a pre or post-contingency case the powerflow does not converge successfully, that case is considered Voltage Unstable. Each successful powerflow solution is checked for violations to the security criteria, including voltage and reactive reserve limits defined in the Criteria File and thermal limits for branches specified in the Parameter file or Rating File. If a Margin File is specified, the base point is then stressed by the specified amount of required margin and pre and post-contingency cases are solved at that stress level. If a case does not solve (powerflow does not converge), it is considered to have insufficient Stability Margin. In case of instability, security criteria violation, or insufficient margin in pre or post-contingency, the base point is deemed Insecure. If Modal Analysis is requested in the Parameter File (with or without the optional Modal Analysis Parameter File) for the pre-contingency or one of the contingencies in the base point (before or after stress), after the specified case is solved, Modal Analysis is performed for that case (and VSAT run terminates). Modal Analysis consists of computing the Jacobian matrix (and reducing it to the V-Q submatrix) and computing a specified number of its smallest eigenvalues and associated eigenvectors. If VQ curve computation is requested, the curves are computed at requested buses after the pre- and post-contingency powerflow solutions. To compute the VQ curve at a bus, an open-var generator is added to the bus to vary its voltage by a specified step size within a specified range. At each voltage step the powerflow is resolved to find the required VAr injection from the generator to hold that voltage. The plot of VAr injections versus the bus voltage represents the VQ curve. Powertech Labs Inc. Page 17

23 During powerflow solutions, special modeling can be used if the appropriate files are provided and proper flags are set in the Parameter File. These include: Generator Capability File: Allows modeling of generator capability curves during all powerflow solutions. Load Conversion File: Allows modeling of voltage dependent loads during post-contingency powerflow solutions. Governor Response File: Allows modeling of governor response to load-generation mismatch caused by contingencies. AGC Action File: Allows modeling of the AGC action to maintain area interchanges following contingencies. Step 4: If Transfer Limit computation is requested by setting the Transfer Analysis flag in the Parameter File and providing the Transfer File, VSAT computes the Secure Range or Region of the transfer. For this, the operating point is moved in specified step sizes in the direction of the Transfer until the security limit is reached. The Transfer File specifies what changes to generation and load are required to make the desired transfer. At each step, VSAT analyses all critical contingencies, determines if any criteria violations exist, and writes the output to the appropriate files, similar to Step 3. If any criteria violations occur, VSAT deems that operating point (transfer level) insecure. The value of the transfer at the last secure point is reported as the transfer security limit. This process may stop before finding the security limit if the transfer target value (user-specified maximum increase or decrease in the transfer) is reached, or the available dispatchable resources are exhausted (dispatched generation or load reached its maximum or minimum). When voltage instability is encountered (either before or after the Stress), if Modal Analysis at the stability limit is requested, it is performed at the last stable case corresponding to the unstable case. For example, if contingency X causes instability at transfer step 12 after the Stress, VSAT returns to transfer step 11, applies the Stress and contingency X, and performs Modal Analysis on this case. If VQ curve computation is requested, during transfer increase (at every step or every n th step) VQ curves are computed for specified buses in pre- and/or post-contingency. Each one-dimensional transfer limit is displayed by a bar chart in the VSAT main window. During the transfer limit computation, the secure value of the transfer is displayed as a growing green section of the bar chart. When the insecure point is reached, the remaining portion of the bar chart is shown as red and the security violation is indicated in the table beside the charts. This provides the user with a quick indication of the security limits for each transfer. In addition, the value of transfer limit is displayed in the Limit column of the top portion of the VSAT main window. After each powerflow solution, the variables specified in the Monitor File are recorded. In addition to these being plotted in the Plots window, the following text output is created: Main output file: Contains descriptions of data and pre and post contingency powerflow solutions Monitored Variable Tables File: Contains tables of all variables specified in the Monitor File Voltage and VAr Reserve Violations Report Overloads Report: if ratings are provided in the powerflow or the Branch Rating File and the overload check flag is set in the Parameter File Modal Analysis Report:if Modal Analysis is requested in the Parameter File VQ Plots:if VQ curves were requested in the Parameter File User Requested Reports: reports of generation, losses, etc., if requested by setting the corresponding flags in the parameter file Security Limit Summary Report Powertech Labs Inc. Page 18

24 VSAT repeats the above process for all scenarios. If more than one server is available, the scenarios will be distributed to the servers and will be computed in parallel. In the case of a two-dimensional transfer, the Secure Region is computed by a similar process except that VSAT traces the boundary of the secure region (separating secure operating points from insecure operating points) rather than finding a single transfer security limit. The secure region is shown in the VSAT main window as a green area on an XY plot with each axis representing one source/sink of the transfer. The boundary points of the secure region and the violation beyond each point are shown in the table beside the XY plot. Step 5: If it is desired to find the Remedial Actions for removing the security violations of an insecure operating point, the RA module of VSAT is run. For this computation, the user specifies the insecure operating point (by the value of the source of transfer at that point) and provides the Remedial Control File and optional Sensitivity Parameter File. The RA module finds the most effective controls (Preventive and, if needed, Corrective) to make the specified operating point secure. The selected controls are displayed in the RA window and reported in the output file. The pre-contingency case at the selected operating point must be Voltage Stable for RA to try to resolve other pre or postcontingency security violations. Step 6: If it is desired to compute the response of an operating point to a contingency by the Fast Time Domain simulation technique, the FTD module of VSAT is run. For this computation, the user selects the contingency and the operating point (by the value of the source of transfer at that point and choice of either the pre-stress or post-stress condition) and provides the Dynamic Data File and optional FTD Parameter File. The FTD module creates the FTD Switching file and FTD Monitor file which the user can modify before running FTD. FTD computes the dynamic response to the selected contingency, displays the monitored bus voltages in the FTD window, and stores them in the output file Contingency Screening Process In general, out of a large number of possible contingencies, only a few contingencies will be critical to voltage stability. The contingency screening feature in VSAT is designed to identify these critical contingencies. The screening does not use any approximation (linearization or extrapolation) and accurately classifies the contingencies based on their exact voltage stability margin. The general process for finding N c most severe contingencies among the full list of contingencies is the following: 1. Starting from the initial point (P o ), compute only the pre-contingency PV curve, in the direction of the Transfer, to find its nose point (P m ). 2. Reduce the transfer from the nose point by s 1 % (or S 1 MW). Call this point P Solve all the contingencies at P 1 and find N 1 contingencies that do not solve. 4. If N 1 = N c, stop. 5. Set the counter i to If N i > N c, reduce the transfer to P i+1 = (P o + P i ) / 2, and find N i+1 contingencies, among the N i unsolved contingencies identified at Pi. Else, increase the transfer to P i+1 = (P i + P m ) / 2, and find N i+1 contingencies among all the contingencies that do not solve at this point (these include the N i contingencies identified at P i which do not need to be resolved). Powertech Labs Inc. Page 19

25 7. If N i+1 = N c, stop. 8. If N i > N c, replace P m by P i, else, replace P o by P i, increase the counter i by 1, and go to step 6. The process stops if the search step (P i+1 - P i ) becomes smaller than a limit, or number of search points (i) exceeds a limit. For example if the full list has 100 contingencies whose voltage stability margins are almost the same, searching for 10 severe contingencies among these 100 would reach a very small search step and too many steps, making the distinction among contingencies meaningless (because of numerical inaccuracies). VSAT has default values for the screening parameters, but for better performance the user may need to specify non-default values for some parameters (specially S 1 ) in the Contingency Screening Parameter file. The screening parameters are: (a) Number of contingencies to be selected for Security Assessment, N c (b) Initial step size for searching for the nose of pre-contingency PV curve, in MW (c) Cut off step size for searching for the nose of pre-contingency PV curve, in MW (d) First step size for screening, S 1, in MW or in percentage (e) Minimum step size for screening (limit on P i+1 - P i ), in MW (f) Maximum number of search points (limit on i) The user may designate a number of contingencies as Must-Run or Don t-run. The program will then include the Must-Run contingencies and exclude the Don t-run contingencies from the selected Nc contingencies (regardless of their severity). Powertech Labs Inc. Page 20

26 2.9 VSAT Structure There are two versions of VSAT installation: 1. Stand-alone: in which the Graphical User Interface (GUI) and computation engines for Contingency Screening, Security Assessment, Fast Time Domain simulation and Remedial Action computation are all integrated into one program. This version does not offer the distributed processing feature. 2. Client-Server: in which the GUI is provided by the client and the computation engines are included in the server. The client does not perform any computation itself. Instead, it distributes the computation tasks to one or more servers that are running on the same computer or other computers on the network. The servers send the results of computations back to the client for viewing/plotting. The servers can not be used independently without the client and the user interacts only with the client (except of course for starting and stopping the server on each computer). The client automatically detects and connects to all running servers on the network and, transparent to the user, distributes the scenarios and contingencies (when there is only one scenario left to compute) to the servers. You may use either version depending on your computational environment, workload and performance requirements. The client-server version is suitable for heavy computations on dedicated computers, and the stand-alone version is suitable in a multi-user setting where one person should not use up the processing power of other users computers VSAT Main Window The Graphical User Interface (GUI), provided by the VSAT client and VSAT stand-alone programs, is used for setting up scenarios, initiating and controlling the computations, and viewing the results. These activities are described in the following sections of this manual. The VSAT main window as shown in Figure 2.7 (after running a number of scenarios) provides: (a) summary of scenarios and their results (b) graphical display of computed security limits (c) tables of insecurities and limits (d) computation progress and error messages (e) pull-down menus and toolbar buttons for opening and saving the Master Scenario (case) file scenario setup and data viewing and editing running Contingency Screening running Security Assessment, pausing the run, stopping the run viewing and plotting the results Fast Time Domain simulation Remedial Action computation controlling servers (in Client-Server version) viewing this manual on line and Help Powertech Labs Inc. Page 21

27 Summary of Scenarios Secure Region Plot and Limit Table for Two-Dimensional Transfer Resize Bar Charts of Transfer Limits Table of Insecurities Resize Tabs to View Run Messages of Scenarios Figure 2.7 VSAT main window You may resize the sections and columns of the main window by clicking on the lines that separate them and dragging them to right/left or up/down. Powertech Labs Inc. Page 22

28 3 Setting Up Scenarios The Scenario File and its data files may be set up manually (created by a text file editor) and then loaded in VSAT, or they may be set up using the VSAT GUI. 3.1 Preparing the Scenarios Manually Preparing the Data Files The powerflow data must be provided in the binary PFB or PSF file. This data can be created from a Powerflow file in PTI Rawd, BPA or other formats by running the auxiliary program CNVPSF, provided with VSAT. To run CNVPSF.exe, open a DOS prompt window and go to the directory where you have stored your powerflow and type, CNVPSF.exe m Powerflow-filename PSF-filename Where m is an integer form 1 to 8, specifying the powerflow format as: 1: PSF ASCII 2: PTI Rawd 30 3: PTI Rawd 29 4: PTI Rawd 27/28 5: PTI Rawd 26-6: IEEE 7: GE EPC 8: BPA Raw Powerflow-filename is the name of your Powerflow file and PSF-filename is the name of the PSF file that will be created by this program. Alternatively, you may double click on CNVPSF shortcut which will start the program in a DOS prompt window (in the shortcut property you can specify the working directory) and prompt you for the format and name of the Powerflow file and the PSF file. The other data files (e.g. Parameter File, Contingency File, etc.) are ASCII text files. The format and function of these files are described in Chapter 9. You may create these files by using any text file editor Preparing the Scenario File Each Scenario File contains the name of all necessary data files for running one VSAT scenario. Data file names may be used in more than one Scenario File thereby allowing the mixing and matching of data files to create different scenarios. The first line of each Scenario File must contain: [VSAT 5.x Scenario] The optional scenario description, which may consist of several lines of text to describe the scenario, must be preceded by the following record: {Description} and they must be followed by: {End description} Powertech Labs Inc. Page 23

29 Each data filename must be specified on one record which contains an identifier, the "=" sign, and the file name enclosed in single quotes as in the following: Identifier = 'file name' where the Identifier is one of the following: Powerflow File PFB File Parameter File Transfer File Criteria File Margin File Contingency Script File Full-Set Contingency File Contingency File Contingency Screening Parameter File Monitored Variable File Interface and Circuit File Generator Capability File Governor Response File AGC Action File Load Conversion File Branch Rating File Modal Analysis Parameter File VQ Curve File Control Mode file FTD files: Dynamic Data File FTD Parameter File FTD Monitor File RA files: Remedial Control File Sensitivity Parameter File The data file names in the Scenario File can appear in any order and only the PFB File (powerflow binary data) and those files that are needed for the computations (depending on the computation options and features specified by the user) need to be specified. There can be an optional End record in the Scenario File as: [END] The program ignores any record starting with "/", blank records, and any record after the End record. The Identifiers are case insensitive and can be preceded and followed by any number of blank spaces. However, their spelling (including spaces between words) is fixed. Tabs must NOT be used as white space (instead of blank space). The file names may specify the absolute or relative path of the file location, e.g. 'c:\vsat\data files\test.ctg' or '..\case5\t1.trf'. Note that in Security Assessment, contingencies are read from the Contingency file and the Full-Set Contingency file is ignored. In Contingency Screening, the full-set contingencies are read from the Full-Set Contingency file and after the top N critical contingencies are found, they are written into the Contingency file. Powertech Labs Inc. Page 24

30 3.1.3 Preparing the Master Scenario File Once a number of Scenario Files have been prepared, their filenames can be specified in a Master Scenario (or Case) File. In this way, the user needs only to provide VSAT with the name of Master Scenario File and all the scenarios in that file will be loaded in. Any number of Master Scenario Files can be kept by the user, each with it s own unique combination of scenarios. The format of the Master Scenario File is as follows: Scenario1_ID, 'Scenario1_Filename' Scenario2_ID, 'Scenario2_Filename' Scenario3_ID, 'Scenario3_Filename' Scenario4_ID, 'Scenario4_Filename' The Scenario_ID is used to identify the scenarios in the GUI and to name the output files as described in Chapter Preparing the Scenarios through VSAT GUI Creating a New Scenario The fastest way of creating a new scenario is to open (Add) an existing scenario (one of your previous scenarios or a test scenario file provided with VSAT), modify it, and save it as a new scenario as described in the next sections. However, you may create a new scenario from scratch as follows. 1. Start VSAT Client or Stand-alone. If there is a Master Scenario File called vsat.vsa in the Starting directory, it will be loaded in and the window will show the scenarios in that file. In that case, you may use File New menu to get a blank VSAT window. Figure 3.1 A blank VSAT main window 2. In the VSAT main window, pull down the Scenario menu and select New. Figure 3.2 Creating new scenario Powertech Labs Inc. Page 25

31 3. The Scenario File specification window appears where you can navigate to (Look in) different directories, specify a File name for the new scenario file and click the Open button. Note that if you specify an existing scenario file, that scenario will be opened instead of creating a new scenario. 4. The Scenario window opens, showing the new scenario, which has no other data file. You need then to click on each data in the list in the left side to specify the required data in the right side. For example, after you click on Parameter, you may either open an existing Parameter file, or specify the required parameters in the right side and save them in a new Parameter file, which will be included in the scenario. See the next section for details on how to open, modify and save the data files. 5. Close the Scenario window (Click Yes in the prompt for saving the changes) to return to VSAT main window Adding Existing Scenario Files If you have existing Scenario Files which were created during a previous session, or which were created manually, you can add them to the existing set of loaded scenarios. In the VSAT main window, pull down the Scenario menu and select Add. The file Open window will pop up where you can find and open (load in) a saved Scenario file. Figure 3.3 Specifying Scenario File Figure 3.4 Specifying data files for the new scenario Figure 3.5 Adding a scenario Figure 3.6 Specifying an existing Scenario file Powertech Labs Inc. Page 26

32 You may load in several scenarios (create new ones or open existing ones). VSAT assigns a sequential number to each scenario and an ID ("Untitled n", where n is a number) to opened scenarios. You may change the ID of any scenario by double clicking on the ID column in the top part of VSAT main window and typing a new value Modifying Scenarios and Data Files After an existing scenario has been loaded or a new one has been created, you can view its details, replace its data files with new files, save it as a new scenario, and change the contents of its data files (remember that Scenario is a collection of data files, and each data file contains a specific data, e.g. Transfer, Criteria, etc.). To view and modify a scenario, select it by clicking on its row in the top part of VSAT main window, pull down the Scenario menu, and select Setup. You may also right click on the scenario row to get the pop-up menu where you can select Setup or just double click on the scenario row (anywhere except the ID column). The Scenario window will appear, with the list of data types on the left section and display of the names and contents of data files on the right section of the window. The two sections of the Scenario window can be resized by clicking on their border line and dragging it to the left or right. The icon beside each data file in the left section indicates the following: Figure 3.7 Changing Scenario ID Figure 3.8 Modifying a scenario A blank-page symbol indicates the absence of the data in the scenario (the scenario does not include the corresponding data file). A text-page symbol indicates the presence of the data in the scenario. Multiple text-pages symbol indicates that the corresponding data file is shared by more than one scenario. If you make changes to this data, and you do not want the changes to apply to all scenarios, save the data as a new file (the other scenarios will use the old file). An exclamation mark in a blank-page symbol indicates that the data is specified in the scenario but the specified data file is not found (for example it might have been moved to another directory). A pencil on the text-page symbol indicates that the data has been changed but not saved yet. Click on Scenario on top of the list in the left section of the Scenario window. The right section will show the scenario filename and description. Click in the Description box on the right and use the Edit menu and commands similar to a text editor to change or retype the description. Figure 3.9 Scenario window, showing Scenario filename and description To view and modify a data file (e.g. the Parameter data) in this scenario, click on the corresponding name (e.g. Parameter) in the data list in the left section of the Scenario window. You will see the data filename and its contents in the right section of the window. To replace the displayed data file in the scenario by another file, click on the browse button on the right of the Filename box. This opens the Select File window, where you can select another file (with similar contents) and open it. Powertech Labs Inc. Page 27

33 For most data files, the data items are displayed in dialog boxes and tables with titles and labels directly related to the file format described in Chapter 9. Refer to the description of each file in Chapter 9 and description of the dialog boxes and windows in Help for the meaning and purpose of each item in these dialogs. For some of the data files, the whole content is displayed in a single text box where it can be edited as in any text file editor. The Edit menu provides common editing commands such as Cut, Copy, Paste and Find. If you click the right mouse button while in the File Contents box, a pop-up menu will provide similar commands as the Edit menu. For the format of these data files refer to Chapter 9. You may save any data (after some changes) in its current file or a new file by choosing Save or Save As from the File menu. To save all changed data types at once in their current files, choose Save All from the File menu. To remove a data from the scenario, select it from the list on the left (to display it on the right) and choose Remove from the File menu. If you change any of the Filenames (by opening another file to replace an existing file, or saving the data as another file) or scenario description, you must save them in the existing scenario file or a new one by choosing Save Scenario or Save Scenario As from the File menu. To close the Scenario window and return to VSAT main window, choose Exit from the File menu. If you try to exit the Scenario window without saving the modified data, you will be asked to confirm to save the changes, ignore the changes or cancel the command (stay in the current window). Figure 3.10 File menu of Scenario window Removing Scenarios If you wish to remove a loaded scenario, select it by clicking on its row in the top part of VSAT main window, pull down the Scenario menu, and select Remove. You may also right click on the scenario row to get the pop-up menu where you can select Remove Viewing Powerflow Data Figure 3.11 Removing scenario If you wish to examine the powerflow data of a scenario, select it by clicking on its row in the top part of VSAT main window, pull down the Scenario menu, and select Open in PSAT. This opens the binary powerflow data in PSAT program where you can view buses, generators, loads, etc. (see the manual of PSAT for details). Note that if you change the data in PSAT and save it in a different PFB file, the scenario will still use the original PFB file. See section 3.3 for viewing and saving the powerflow data in the Scenario window Archiving Scenarios To archive a scenario, select it by clicking on its row in the top part of VSAT main window, pull down the Scenario menu, and select Archive. You may also right click on the scenario row to get the pop-up menu where you can select Archive. This creates a Zip file of the scenario with all its data files. Powertech Labs Inc. Page 28

34 3.2.7 Creating and Saving a Master Scenario (or Case) FILE Once the Scenario Files have been created, the collection of scenarios and their IDs shown in the top part of VSAT main window can be saved in one Master Scenario File (or Case File). From the VSAT main window, pull down the File menu and select Save (if you wish to overwrite the existing Master Scenario File) or Save As (if you wish to create a new Master Scenario File). Any number of Master Scenario Files can be created and saved allowing the user to mix and match a set of scenarios to create a wide number of different execution runs. Only one Master Scenario File can be loaded into VSAT at a time Adding Scenarios Using A Master Scenario File Figure 3.12 File menu for saving and opening Master Scenario files If you have previously prepared a Master Scenario File (either manually or using the GUI to create and save it) you can open that file by pulling down the File menu in the VSAT main window and selecting Open. The File Open window will popup where you can select and Open the desired file. Once opened, all the scenarios in the selected Master Scenario File will be loaded and will appear in the VSAT main window. The scenarios can then be viewed and modified, if needed, in the Scenario window as described before Archiving All Scenarios To archive all scenarios, pull down the File menu, and select Archive Case. This creates a Zip file of all the scenarios with all their data files Exiting VSAT To exit (close) VSAT, pull down the File menu in the VSAT main window and select Exit. If you have not saved the Master Scenario File (as described above) after adding or removing scenarios or changing their IDs, VSAT will ask you to confirm to save the changes in the current Master Scenario File, ignore the changes or cancel the command (stay in the current window). Powertech Labs Inc. Page 29

35 3.3 Powerflow Data and Conversion to PFB After you select a scenario in the VSAT main window and click on Setup to go to the Scenario window (as described in Section 3.2.3), if you click on Powerflow on the left side, the right side of the window shows the Powerflow as well as PFB or PSF filename. If the base poweflow data for the scenario is provided in the PFB or PSF file (e.g., a PFB file created by any DSATools TM program), the Powerflow file is not required. Otherwise, the Powerflow file must be specified and converted to PFB file before Contingency Screening, Security Assessment or any other computation. Also, if you change the Powerflow file or its contents, you must re-convert it to PFB before any computation. To specify/change the files, click on the browse button on the right of Powerflow Filename or PFB or PSF Filename box to open the Select File window. In this window, find the desired file and click the Open button. If the PFB file does not exist (it needs to be created for the first time) you can enter a new name in the File Name box of the Select File window and click the Open button. To convert the Powerflow file to PFB file, first specify its format by Figure 3.13 Converting powerflow data to PFB selecting an item in the Powerflow Format pull-down list, then click on the Convert to PFB button. The conversion will start and a message window will appear, showing the progress and possible error and warning messages. You can examine and even modify the PFB data by clicking on the Open PFB in PSAT button. This starts the PSAT program, where you can examine data of buses, generators, loads, etc., modify the data if needed and save the PFB file (see the manual of PSAT for details). If in PSAT you save the data in a different PFB file, the scenario will use the new file. 3.4 Data Views As described in Section 3.2.3, when you double click on a scenario in the VSAT main window, the Scenario window appears, showing the list of all data files (data tree) in the left side. By clicking on each data in this list, the right side of the Scenario window shows the filename and its contents for that data. For each data, the titles, labels, headings and contents of dialog boxes and tables in the right side of the Scenario window are directly related to the format of that data file as described in Chapter 9. Refer to Chapter 9 and description of the dialog boxes and windows in Help for the meaning and purpose of each data item in these dialogs. The following describes the general and specific aspects of data views General Features of Data Views Every data in the data tree (e.g., Criteria) is read from and save to a data file. The name of this file is displayed in the File name box in each data view. To replace a data file by another file, click the Browse button beside the File name box to open the Select file dialog and choose the other file to Open. The data view will show the contents of the selected data file. To save the data in the same file (after you change some of the data items) or in another file, use the Save or Save As commands of the File menu. Opening another data file or Powertech Labs Inc. Page 30

36 saving the data to another file (a file other than the current one in the scenario) changes the previous filename to the new filename in the scenario. To keep the new file in the scenario, use the Save Scenario or Save Scenario As commands of the File menu. Most data files (e.g., Criteria), as described in Chapter 9, consist of singular data items (e.g., Name of criteria data) and groups of data records (e.g., Voltage Limit groups). The composition of each group (i.e., buses, generators or loads belonging to the group) is specified by including and/or excluding areas, zones, buses, etc. Each singular data item is displayed in a dialog box with a label the same as the item s name in the data file. The Description dialog box shows the data description records (one or more lines of text). The content of these dialog boxes can be changed by typing in new values and pressing the Enter key or using the Cut, Copy and Paste commands of the Edit menu and the right-click pop-up menu. The groups of data records are shown in tables, with one or more columns that identify the groups by a sequence number and/or name, and show their parameters or attributes (e.g., High Limit, Low Figure 3.14 Example of data view Limit, etc.). You can change the value of these parameters by clicking in each cell of the table and entering a new value and pressing the Enter key or clicking another cell to complete the change. In some cases, a pull-down list appears in the cell and you can choose a value from that list. You can add and delete rows in the group table (and other tables) by using the Add and Delete buttons right above the table. In some tables, there is a pull-down list beside the add button from which you select one item to be added. In other tables the add button simply adds an empty row. In either case, you must type in the required data in the empty cells of the added row. You may enter a default indicator (e.g., 0 or 1) in some of the cells which can have a default value as described in Chapter 9. To delete a row, select it by clicking on it and then click the Delete button. When you select a row of the group table by clicking on the group number or a cell in that row, the composition of that group is shown in the composition table on the right of the group table. The heading of the composition table shows which row was selected in the group table. The composition in general consists of: Include area = area-list Include zone = zone-list Include bus = bus-list Include kv = kv-list Exclude area = bus-list Exclude zone = zone-list Exclude bus = bus-list Exclude kv = kv-list The first column of the composition table shows the record identifier (e.g., Include area, Include zone, etc., without the = sign), and the second column shows the area/zone/bus/kv list for that record. You can change this list by clicking on it and entering a new number (or name), a list of numbers (or names) separated by, Powertech Labs Inc. Page 31

37 (e.g., 14, 15, 23 ) or a range specified by two numbers separated by : (e.g., 101 : 125 ). See Section for all the rules for specifying these lists. The order of the Include and Exclude records is very important and affects the composition of the group as described in Section To add a new row to the composition table at a specific location, first click on an existing row after which the new row would be added, then click the Add button (or the pull-down list beside it) right above the table. This opens the pull-down list from which you can choose one of the record types (e.g., Include area, Include zone, etc.) to be added to the table. You must then type in an area/zone/bus/kv list in the second column of the added row. If the Name option is selected in the Parameter data (see Section 9.4), areas, zones and buses in the Include/Exclude lists and everywhere else in all data files must be specified by their names (exactly as they appear in the powerflow data), otherwise, they must all be specified by their numbers. As in the example in the above figure, some data files contain more than one type of data groups or records. In these cases the tables of groups/records of each type are shown under a separate tab (e.g., Voltage Limits, Delta- V Limits, etc.) Parameter Data View To view and modify the parameter data click on Parameter in the data tree of the Scenario window. The right side of the window shows the value of parameters in the Parameter file in dialog boxes, organized under 8 tabs (Functions, PF Controls, etc.). For those parameters which are not specified in the file, their default value will be shown. You may change the value of any parameter by typing a new value or choosing a value from the drop-down list in the dialog boxes. Refer to Section 9.4 (Parameter File) for the description of function (meaning) of each parameter and the type and range of its value. The Report range and Zone report tables show the include area/zone/bus records similar to other composition tables described in Section Figure 3.15 Parameter data view Powertech Labs Inc. Page 32

38 3.4.3 Transfer Data View To view and modify the transfer data, click on Transfer in the data tree in the Scenario window. The right side of the window shows the contents of Transfer file under 4 tabs. The General tab shows the transfer type as well as the Name, Description, Step Size and Cutoff Step Size in the Transfer file. If the transfer does not include Source Y, the transfer type will be one-dimensional, otherwise it will be twodimensional. To add Source Y to a one-dimensional transfer, click the 2-Dimensional radio button and to delete Source Y of a twodimensional transfer, click the 1- Dimensional radio button. Figure 3.16 Transfer data view The Source X tab shows the name of Source X and its Decrease Limit, Increase Limit and Source/Sink Groups table. This table shows the generation, load and DC converter groups belonging to Source X, their Share and the load scale option. Similarly, the Source D (Y) tab shows the name, limits and groups of Source D (Y). Refer to Section 9.5 (Transfer File) for the description and purpose of these data items. To add a Generation Scale, Generation Schedule, Load Scale or DC Converter group to Figure 3.17 View of Generation Schedule in Transfer Source the Source/Sink Groups table, click on the Add button above this table and select a group from its drop-down list. You must type in a value in the Share cell and select a value from the pull-down list in the Option cell for the added group, unless these cells are grayed out. You must also specify the composition of the added group as described below. As in other tables, to delete a group click on its row in the table and then click the Delete button. Click on a load or generation scale group in the table to view and edit its composition (included and excluded areas/zones/buses/kvs) in the right table as described in Section Powertech Labs Inc. Page 33

39 Click on a generation schedule group to see the list of generators belonging to this group in the right table. You can change the data in this table by clicking in a cell and typing a new value. To add or remove a generator in this table, use the Add and Delete buttons right above the list. If you first click on a row to select it, then click the Add button, the new row will be added right after the selected row. The Delete All button above the table deletes all rows. Click on a DC converter in the table to view and edit the converter specification and its participation factor in the right of the Source/Sink Group table. Each participating converter must be specified in one DC converter group (each DC converter group consists of one converter). In this way, converters of a multi-terminal DC network can participate in the transfer by any given factor. Figure 3.18 View of DC Converter in Transfer Source Contingency Script View To view and modify the contingency script data click on Script under Contingency group in the data tree in the Scenario window. The right side of the window shows the contents of Contingency Script file in two tables. This data consists of contingency Groups, and each group consists of one or more Subgroups of different types, e.g., Outage Branch, Outage Generator, etc. The composition of subgroups is specified by including and excluding areas, zones, buses, kvs and/or MVAs. See Section 9.9 for details of contingency script data. The left table in the Contingency Script view shows the contingency groups by a sequential number and lists their subgroups. The right table shows the composition of each subgroup selected in the left table. To add or delete a contingency group, click on the Add or Delete button on the top-left corner of the Contingency Groups/Subgroups table. To delete a group first select it by clicking on one of its Subgroups. To add a Subgroup in an existing Group, first select the Group by clicking in its Subgroup cell, then click on the Add button above the Figure 3.19 Contingency Script data view Powertech Labs Inc. Page 34

40 Subgroup column and select an item from the drop-down list. To delete a Subgroup, select it by clicking on it in the Subgroup column and click the Delete button above this column. To define the composition of an added Subgroup or view and change the composition of an existing Subgroup, click on it in the Subgroup column of the left table. The right table will show the included and excluded areas, zones, etc., in the subgroup. Data can be added, changed or deleted in this table similar to other composition tables as described in Section To run the script and create contingencies, a) If the script data has been changed, save the script file by using the Save or Save as command of the File menu. b) Choose Full-set or Screened in the Create Contingency File box by clicking on one of the radio buttons depending on which file you want to be created by the script. Make sure a filename has been specified for the Full-set or Screened Contingency in the scenario (in the Contingency data view) for the script to create it. If the file exists, it will be overwritten by running the script. c) Click the Run button in the Create Contingency File box and view the messages that show running of the script Contingency Data View To view and modify the contingency data of a scenario, click on Full-set or Screened under Contingency group in the data tree of the Scenario window. The right side of the window shows the Full-set or Screened Contingency window. These views, which are similar except for the Screen button described below, show the list of contingencies on the left, and the contingency definition on the right. On the right of the Contingency table there is a list of all types of outages (or changes) that can be included in each contingency. By clicking on each contingency in the left table, the symbol and number beside each outage type in the list indicate whether the selected contingency contains that type of outage. The box below this list shows the complete definition of the selected contingency (all records of line outage, generator outage, etc.) as described in Section 9.10 (without the {Contingency }, Contingency Name and {End Contingency} records). Figure 3.20 Contingency data view You can change the name of each contingency by clicking in the Name column and typing in a new name. Powertech Labs Inc. Page 35

41 Each contingency is flagged as Must Run, To be Screened (or Run ), or Don't Run as shown in the Run Flag column. To change the run flag of a contingency, click on it and from the drop-down list, select a different run flag. To delete a contingency, select it by clicking in its row in the Contingency list and then click on the Delete button Figure 3.21 Contingency name and Run Flag above the table. Click on the Add button above the table to add a contingency. You must type in a name and select a Run Flag for the added contingency in this table (as described above) and then specify its outages. To specify or modify the outages of a contingency, first select the contingency by clicking on its row in the Contingency table to view its outages in the Outage box. Then to add, delete or modify an outage type, for example a branch outage, double click on Branch in the outage list on the right of the table. This opens the Edit Outage Branch window where the branch outages of the selected contingency are shown in a table. You can add or delete outages in this table by using its Add and Delete buttons, and change the specification of each branch outage by typing in the cells of this table. When finished Figure 3.22 Edit Outage Branch window changing the outages, close the Edit Outage Branch window by clicking on its Close X button on its title bar. Similarly you can add, delete or modify Bus outages, Generator outages, etc., for each contingency. See the description of outages in Section 9.10 for specifying the required data in the Edit Outage windows. The changes made in these windows will be reflected in the Outage box. For security assessment of each scenario, (a) If you don t want to screen the contingencies before security assessment, specify (and change and save) the Screened Contingency file in the Screened Contingency view (or create it from the contingency script). In this case you don t need to specify the Full-set Contingency file. (b) Otherwise, specify the Full-set Contingency file (or create it from the contingency script) and Contingency Screening Parameter file and run the screening to create/replace the Screened Contingency file. To run the screening, after saving all changed data files in the Scenario window (you can use the Save All command of the File menu), click on the Screen button in the upper right corner of the Full-set Contingency view (in the Client-Server version, you must have a server running; see Section 4.3 for details). After screening, you may examine, modify and save the created Screened Contingency data before security assessment. Powertech Labs Inc. Page 36

42 3.4.6 Generator Capability Data View To view and modify the generator capability data of a scenario, click on Generator Capability in the data tree of the Scenario window. The right side of the window shows the Capability Data, Capability Curves and Fixed MVAr Limits in the file under three separate tabs. The Capability Data and Fixed MVAr Limits tabs show the corresponding data in a table where you can add or delete rows and change the data in each cell similar to other tables. The Capability Curves tab shows the capability curves in two tables. Each Capability Curve group in the data file consists of the generator bus, ID, terminal voltage, and the points of the curve. Each such group is shown in the left table as one row with the first three data items. The points of the curve are shown in the right table. Use the Add and Delete buttons above the left table to add and delete groups of capability curves data. To view and modify the points of Figure 3.23 Generator Capability data view the curve in each group, select that group in the left table by clicking on its row. The right table will show the points of the curve as a set of P, Q-hi and Q-lo values. Use the Add and Delete buttons above the right table to add or delete points on the curve or type in new values in each cell to change it. See Section 9.12 for full descript of this data. The groups of curves for each generator and the points of each curve must be specified in the correct order described in Section Powertech Labs Inc. Page 37

43 3.4.7 Load Conversion Data View Click on Load Conversion in the data tree of the Scenario window to view and modify the load conversion data of the scenario in the right side of the window. The load models specified in the data file are shown in the Exponential Load Models table. Each row shows one model by its model number and 12 coefficients and exponents for real and reactive part, as described in Section 9.15.You can modify these values by typing new values in the cells, or add and delete rows by using the Add and Delete buttons above this table. The data for the load conversion groups are shown in three tables at the lower part of the window. The Group table simply shows the list of groups by a sequential group number. Groups can be added and deleted by using the Add and Delete buttons above this table. When you select a group by clicking on it in the Group table, the loads belonging to the selected group are shown in the second table and the specification of load components for this group is shown in the third table. You can add or delete rows or change the existing ones in the second table (Loads of Group n) similar to other composition tables as described in Section Figure 3.24 Load Conversion data view The Load Components table allows up to 5 components to be specified for the selected group. The component in the last row, which is Constant Power, is not specified explicitly or saved in the data file. If the group s load has, for example, only 3 components (beside the constant power component), two rows in the table remain blank. You can select the type of any of these 5 components from the drop-down list in the Type cell. If the selected type is Exponential Model, the model number must be entered in the Model cell (this must be one of the models defined in the Exponential Load Models table in this data or in the powerflow data). To delete one of the components, change its type to blank. The percentage of each component in the total real and reactive load is shown, and can be changed, in the last two columns of the Load Components table. The percentage of the constant power component in the last row is computed as 100 minus the sum of percentages of the other components. If all 5 components have been specified (i.e., none is blank ), the percentage of constant power component must be zero since there is no room for a sixth component in the model Other Data Views By clicking on other data types in the data tree of the Scenario window, the corresponding data is shown and can be modified in the right side of the window in tables and dialog boxes. These are similar to the general tables described in Section Powertech Labs Inc. Page 38

44 4 Running VSAT Once scenarios have been loaded into VSAT, either by opening a Master Scenario File, or through the New and Add commands of Scenario menu, they will appear in the top part of VSAT main window. The Status column of the VSAT main window will show "Waiting" for all scenarios. Figure 4.1 VSAT main window before running scenarios. 4.1 Starting and Controlling the Servers The Stand-alone VSAT does not require additional servers. But if you have installed the Client-Server version, before you can run VSAT you need to start the servers on the computers that you wish to use. You may start one (or more) server on the same computer that runs the client as well as any other computer on the network. For details on configuring your system for distributed processing, see Chapter 7. On the Server: To start the server on each computer, use the Start Programs VSAT VSAT Server menu. This starts the server in Server-Output directory. Make sure you use the Start menu shortcut and not click on the VSAServer.exe itself to start it, so that the server starts with correct parameters and working directory. As each server starts, a window appears showing the port number of the server and its status (initially Waiting for Client connection ). To disable each server from responding to clients, clear the check mark by clicking on it in the Enable Server box. This is useful for having the full use of the server computer for a period of time for other applications. Click on this box again to enable the server. When the server is enabled, to prevent it from Figure 4.2 VSAT Server window responding to clients other than the one running on the same computer, click the Local Client Only box to get a check mark. This is useful when there are other VSAT users on the network and you want to prevent them from using your server. Clear the box by clicking on it to enable the server for all clients. To stop the server, click the Stop button. Any computations that might be still running will be interrupted and its results will be lost. Powertech Labs Inc. Page 39

45 The Server Messages box shows messages about the client communications and computations. You may clear the messages by right clicking in this box and selecting Clear. You may minimize the server window after it is started since you interface with VSAT through the client. When the server window is minimized, only a small icon is visible on the system tray on the task bar. This icon will flash OL when the server is in use. By holding the mouse over the icon, a tip will appear, showing the status of the server. You may right click on this icon to get a menu for controlling the server. On the Client: Figure 4.3 Server icon menu To control the servers from the client side and to verify that the client has found the servers, pull down the View menu of the VSAT main window and select Servers. This opens the Server List window. Broadcast to find servers Figure 4.4 View Servers menu Manually add a server Enable/Disable a server Figure 4.5 Server List window To find the running servers on the network and update their status, click the Broadcast button. After a short delay for response from the servers, all running servers will appear in the list with Status Free (if they are not used by another client) or Busy (otherwise). To enabled or disabled a server for this client only, click on it in the Enabled column and select "Enabled" or "Disabled" from the drop-down list, or click on the Enable/Disable button. Disabled servers will not be used by this client. If a running server is missed by the client, you can add it manually to the list by clicking the Add button. The New Server window will popup. Enter the server name or IP address and port number then click OK. Generally the list shows all running servers and you don t need to manually add servers or click the Broadcast button to update the list. 4.2 Converting Powerflow Data Figure 4.6 Adding a server Before any computation, if the powerflow data of a scenario is contained in a file other than a binary PFB (or PSF) file, you must convert it to PFB by the following procedure: Powertech Labs Inc. Page 40

46 1. Double click on the desired scenario row in the top part of the VSAT main window to open the Scenario window. 2. Double click on Powerflow on the left side, to see the Powerflow dialog on the right side of Scenario window. 3. If needed, specify or change the Powerflow Format, Powerflow Filename and PFB or PSF Filename in this dialog by clicking on the pull-down or browse button beside each box. Figure 4.7 Converting Powerflow data 4. Click the Convert to PFB button and check the messages that appear to make sure the data is correctly converted and saved in the PFB file. 5. Exit Scenario window. See Section 3.3 for more details. 4.3 Screening Contingencies If you have specified the (Screened) Contingency data for all scenarios (whose Contingency Analysis parameter is True in the Parameter data), you can run the Security Assessment without further screening of contingencies. But if for a scenario this data is not specified or needs to be updated (if the Powerflow, Transfer or Margin data have changed since the previous screening), you must run the Contingency Screening for that scenario to create/update the Screened Contingency data from the Full-Set Contingency data. This is done in two ways as follows. From the Main Window: You can go to the Screening window directly from the VSAT main window if the scenarios are setup and there is no need to modify the data. For this, pull down the Analysis menu and select Contingency Screening. This opens the Contingency Screening window where there is a tab for each scenario. To perform the screening for a scenario of interest, click on its tab. The left side of the window shows the list of contingencies specified in the Full-Set Contingency File. The right side of the window shows the list of contingencies in the Contingency File if this file exists. Otherwise, the right side will be empty. Figure 4.8 Opening Contingency Screening window Powertech Labs Inc. Page 41

47 To start the screening for the selected scenario, click on the Run button on the upper right corner of the window. The Message window will appear, showing the messages and progress of the computation. Check these messages to make sure the Screened Contingency data is created correctly, then close the Message window by clicking on its Close (x) button on the upper right corner. When the screening completes successfully, the screened contingency list is stored in the Screened Contingency file and a message indicating the completion of screening appears on the status bar at the bottom of this window. You need to repeat this process for every scenario that needs screening (click on its tab, then click the Run button). When finished, close the Screening window by clicking on its Close (x) button on the upper right corner to return to the VSAT main window. From the Scenario Window: Figure 4.9 Contingency Screening window Alternatively, you can screen the contingencies from the Scenario window, especially when you need to modify the data and repeat the screening. For this: 1. Double click on the desired scenario row in the top part of the VSAT main window to open the Scenario window. 2. Double click on Full-Set Contingency on the left side, to see the Full-Set Contingency dialog on the right side of Scenario window. 3. If needed, replace the Full-Set Contingency file, and/or change Run flag and description of individual contingencies in this Figure 4.10 Contingency screening in Scenario window Powertech Labs Inc. Page 42

48 dialog. See Section for more details. 4. Similarly, if needed, modify the Contingency Screening Parameter data. 5. Save all changed data, including the Scenario file, using the File menu of the Scenario window. 6. Click on the Screen button in the upper right corner of the Full-Set Contingency dialog. This opens the Screening window, where you can run the screening as described above. 7. Check the messages that appear to make sure the Screened Contingency data is created correctly. Then close the Screening window by clicking on its Close (x) button on the upper right corner 8. You will return to the Screened Contingency dialog, where you can examine and, if needed, modify and save the screened contingencies for the security assessment run. 9. If the list of screened contingencies is not satisfactory, modify the parameters or the Full-Set contingencies and repeat the screening. Otherwise, 10. Return to the VSAT main window by using File Exit menu of the Scenario window or its Close (x) button. 4.4 Enabling/Disabling Scenarios Since a large number of scenarios can be loaded in VSAT either manually or through a Master Scenario File, the user may wish to run only selected Scenarios without creating a new Master Scenario File. When loaded, all scenarios are set to run as indicated by a check ( ) mark in the Run column. Clicking on the check box toggles the Run flag (between set and clear) to run or not to run the scenario. The Analysis menu allows you to set or clear all Run flags or invert (toggle) them. Figure 4.11 Enabling/disabling scenarios for run 4.5 Running the Security Assessment To run the Security Assessment, pull down the Analysis menu in the VSAT main window and select Run Security Assessment, or alternatively, hit the Run button on the tool bar. This will run the security assessment for all the enabled scenarios by distributing them to available servers. (If you haven t specified the Contingency file or wish VSAT to update this file, you need to run the Contingency Screening as described in Section 4.3 before running the Security Assessment). When the run is completed, the VSAT main window will show: "Finished" in the Status column Transfer limit in the Limit column (for one-dimensional transfer only; two-dimensional transfers do not have a single limit) Bar charts of secure ranges and table of security limits and violations of one-dimensional transfers under the Range Scenarios tab Figure 4.12 Running Security Assessment XY plot of secure region and table of security limits and violations of each two-dimensional transfer under separate tabs Run messages of each scenario under separate tabs in the Message window (lower part of the main window) Powertech Labs Inc. Page 43

49 4.6 Viewing the Limits and Violations VSAT main window provides a graphical and tabular display of the computation results. Transfer in the Base Case Transfer Limit Transfer in the Base Case Insecure Transfer Levels Transfer Limit Contingency that causes insecurity Type of insecurity Figure 4.13 Security limits of one-dimensional transfers When the run starts, the Base Level column in the Scenario table shows the value of source or sink (Source X or Source D) for one-dimensional transfer, or Source X and Source Y for two-dimensional transfer, in the base case. When the run is completed, the Limit column shows the value of source or sink at the transfer limit. For one-dimensional transfer, right click on the Source(s) column in the table allows you to toggle between the source and sink. For scenarios with one-dimensional transfer or no transfer, under the Range Scenarios tab, a bar chart shows the progress of the computation in the form of an advancing green and yellow bar. When the computation is completed, the green part of the bar indicates the secure range of the transfer. The insecure (or un-computed) range of the transfer becomes red. The yellow part indicates either one step of transfer (distance between the last secure and first insecure transfer level) or, if Transfer Analysis is To Maximum (see section 9.5), all the steps where insecurities are found. When the base case is insecure and transfer is reversed (see section 9.5), the reversed range of transfer is shown in orange and the point where the case becomes secure is shown in green. The bar represents either the source or sink of the transfer as selected in the Source(s) column of the Scenario table (which can be toggled by right click in the Source column). The blue arrow indicates the base value and direction of change in the source or sink. Powertech Labs Inc. Page 44

50 The table beside the bar charts shows the detail of insecurities related to the yellow (or orange) part of the bar charts. It shows the value of source and sink where insecurity is found, the contingency that causes insecurity and the type of insecurity (violated criteria). For scenarios with Transfer Analysis = To Maximum, computation continues beyond the first insecurities (where the bar changes to yellow) until the pre-contingency case becomes voltage unstable, or the maximum transfer is reached (where the bar changes to red). All insecure points and violations are listed in the table beside the bar charts. Initially, one row shows the first insecurity for the scenario (as in the above figure), but by clicking on the + sign beside the row, it expands to show all insecurities. In this case, the + sign changes to - sign which can be clicked to collapse the list back to one row. Figure 4.14 Security limits with Transfer Analysis = To Maximum For scenarios with one-dimensional transfer, if the base case is insecure, the Limit column of the Scenario table shows Insecure, but if the transfer is reversed and a secure point is found, the value of Source X (or D) at the secure point is shown in the Limit column inside brackets. For scenarios without a transfer ( Transfer Analysis = No in the Parameter data), the transfer columns remain blank. If there are no violations (the case is secure), the Limit column of the Scenario table and the Violation column of the table beside the bar charts show Secure and the whole bar is shown in green. Otherwise, the Limit column of the Scenario table shows Insecure, the whole bar is shown in red and the insecurities are shown in the table beside the bar charts. For scenarios with two-dimensional transfer, under separate tabs with the Scenario ID label, the progress of the computation is shown in the form of an advancing green line in an XY plot region that becomes a closed area upon completion of computation. The green area inside this closed line is the secure region of the transfer. The points on the boundary of the secure region are the security limits and are shown in the table beside the plot. Figure 4.15 Security limits of two-dimensional transfers The violation type (VAr reserve violation, Margin violation, etc.) at the boundary points is shown on the plot with different colors. By clicking on a boundary point on the plot, the coordinates of that point are displayed and the corresponding row of the limit table is highlighted. Powertech Labs Inc. Page 45

51 4.7 Viewing the Messages During the computations, messages and results of each scenario are stored in the Progress Report and other output files (see Chapter 8). Key messages are also displayed in the Message window and can be viewed during computations. The Messages window is initially positioned in the lower part of the VSAT main window. You may tear off this window by holding its handle (the bars on the right border) and dragging it to another location. If you close the Message window (by clicking its x button after you tear it off from the main window) you can reopen it from the View Messages menu of the VSAT main window. For each scenario there is one tab on the lower border of the Message window. There is also one tab marked General that is used for common messages such as reporting total time spent on all of the scenarios, etc. To access the messages of a scenario, click on the corresponding tab. To clear the messages after a run, click the right mouse button in the Message window and select Clear from the menu that will pop-up. You may also select Copy or Save from this menu to copy the messages to the clip board or save them in a text file. Figure 4.16 Message window (after separated from VSAT main window) Powertech Labs Inc. Page 46

52 4.8 Live Plot of Monitored Variables For simple on-the-fly plotting of monitored variables during or after Security Assessment runs, open the Security Assessment Plots window from the Results Live Plots menu of the VSAT main window. In this window, you can choose different monitored variables (bus voltages, interface flows, etc.) of different scenarios to have them plotted in the Plot Area (upper left section) of the window. This area can show the plots of one-dimensional scenarios or those of two-dimensional scenarios (monitored variables of one- and two-dimensional scenarios can not be plotted together). For more comprehensive plotting, customizing and printing of monitored variables use the DSA Output Analysis module. Figure 4.17 Results menu Figure 4.18 Security Assessment Plots window The Filtered Quantities list (in the lower right side of the window) initially shows the monitored precontingency bus voltages of the first scenario. To change this list to show other monitored variables: Pull down the Scenario list (by clicking on its down-arrow button) and click on any scenario to select it. Scroll the Contingency list and click on any contingency to select it, or click the right mouse button on this list and the Select All button will pop-up. Click on this button to select the pre-contingency and all post-contingency cases. Pull down the Quantity Type list and click on any monitored variable type to select it. Powertech Labs Inc. Page 47

53 The monitored variables of the selected scenario / contingency (or contingencies) / type will show up in the Filtered Quantities list. You may use the Quantity Filter to reduce the list to those that match the filter. For example if you enter "ABC*" in the Quantity Filter box, only those monitored variables with a name (label) that starts with ABC will be listed. From this Filtered Quantities list, you select the rows to be plotted by clicking on them. You may select multiple rows by holding down the Shift or Control key while clicking on more rows. From the Selection menu, you may plot all the rows or only the selected row(s) of the Filtered Quantities list by choosing Add All Filtered Quantities or Add Selected Filtered Quantities, respectively. You can also quickly add one row of the Filtered Quantities list to the plot by double clicking on that row. The Plotted Quantities list (in the lower left side of the window) shows the plotted quantities. By clicking on a row in this list, that row and the corresponding curve on the plot will be highlighted (selected). Here also you may select multiple rows by holding down the Shift or Control key while clicking on more rows. Also, if you click on the end points of a curve on the plot, that curve and the corresponding row in the Plotted Quantities list will be highlighted. Another click on this curve will deselect it. From the Selection menu, you may Remove All Plotted Quantities or Remove Selected Plotted Quantities from the plot. Figure 4.19 Selecting quantities for plotting For one-dimensional scenarios, the horizontal axis of the plot shows the value of transfer's source (X) and the left vertical axis shows the value of monitored variables (they are all plotted on the same scale). For two-dimensional scenarios, the points on the horizontal axis correspond to the boundary points of Figure 4.20 Plotted Quantities the secure region. In addition to the selected monitored variables, two more curves are plotted to show the value of two sources/sinks of the transfer (X and Y) of these boundary points. The left vertical axis shows the value of monitored variables and the right vertical axis shows the value of X and Y. Powertech Labs Inc. Page 48

54 In addition to being able to resize the whole Security Assessment Plots window, you can resize its four sections by holding the Split lines above and between the borders of Filtered Quantities and Plotted Quantities boxes and dragging them up/down or left/right. 4.9 Viewing and Plotting the Results Details of security violations and transfer limit, along with monitored variables and other user-requested reports of computed scenarios are saved in the output files. To view/plot the results, open the DSA Output Analysis module by the Output Analysis command of the Results menu in the VSAT main window. See the DSA-OA Manual for details. Powertech Labs Inc. Page 49

55 5 FTD The FTD module of VSAT performs the Fast Time Domain simulation of a selected contingency at a selected operating point. This chapter describes the data requirements and operation of FTD. 5.1 FTD Data Requirement Four data files are needed for FTD run: 1. Dynamic Data: provides the model for all dynamic devices and loads 2. FTD Parameter Data: provides the parameters for FTD simulation 3. FTD Monitor Data: specifies the quantities to be monitored during FTD simulation 4. FTD Switching (Contingency) Data: describes the contingency to be simulated The models and format of the Dynamic data, as well as the FTD Monitor and Switching data, are described in the FTD Model Manual. Some of the models apply only to the full time domain simulation and are ignored in FTD. VSAT assigns default values to all FTD parameters. You may modify these parameters and save/read them to/from files. The FTD Monitor and Contingency data are automatically created by VSAT from the Security Assessment Monitor and Contingency data. You may modify these data or replace them with previously prepared data files. To select, view and modify the first three data files for a scenario: 1. Double click on that scenario in the VSAT main window to go to the Scenario window, and in the left section of that window click on Dynamic, Parameter or Monitor under Fast Time Domain group to examine, modify and save these files (as described in Section 3.2.3). Figure 5.1 FTD Parameter view in Scenario window Powertech Labs Inc. Page 50

56 2. If the FTD Parameter file is not specified in the Scenario file, the Filename box in the FTD Parameter dialog shows "No file entered" and default values are shown for all parameters. You may type in new values for each parameter (described in Section 9.22) and save the data in a new file by using the File Save As menu. Instead, if you have a previously saved file that you wish to use in this scenario, use the browse button on the right of the Filename box to find and open that file. 3. If the FTD Monitor file is not specified in the Scenario file, the Filename box in the FTD Monitor dialog shows "FTD_Untitled.fmn" and the File Contents box below shows the data created automatically from the VSAT Monitor file. You may edit this data and save it in a new file by using the File Save (or Save As) menu, or you may use the browse button to find and add a previously saved FTD Monitor file to this scenario. The contents and format of Monitor data and Dynamic data are described in the FTD Model Manual. 4. If you changed a data filename, save the Scenario file by using the File Save (As) Scenario menu and Exit the Scenario window. 5.2 Running FTD To run the FTD module, in the VSAT main window pull-down the Analysis menu and select Fast Time Domain, or click on the FTD button on the tool bar. The FTD window will appear where you can select a scenario, select an operating point, select a contingency, and run the FTD simulation of that contingency at that operating point. The steps to run FTD are the following: 1. In the Select Scenario pull-down list, select the desired scenario. 2. Under the Contingency tab, from the Select Contingency pull-down list, select a contingency. VSAT automatically converts the selected contingency, as defined in the VSAT Contingency data, to FTD Switching (Contingency) data and saves it in FTD_untitled.swt file. The format of Switching data is described in the FTD Model Manual. You may modify this data and save it in a new file by using the Edit and File menus. If you have created and saved a Switching file previously and wish to use that data instead of the FTD_untitiled.swt file, click on the browse button on the right of the Filename box to find and open that file. Figure 5.2 FTD window Powertech Labs Inc. Page 51

57 3. Select the operating point by typing the value of the transfer's source X in the Select the Operating Point edit box. To select the base (initial) operating point, if the scenario does not involve a Transfer ( Transfer Analysis = No in the Parameter data) you must type zero (0) in this edit box, otherwise, you must type in the value of source X at the base point (as shown in the VSAT main window). 4. If the Margin data (criteria) is specified for the selected scenario, beside specifying the value of source X, you may click in the Stress box to select it (a check mark appears in this box). In this case, the selected operating point will be stressed by the specified margin criteria and then the contingency will be applied at that point (so you can verify whether the stability margin of the selected contingency is larger or smaller than the specified criteria). If you deselect the Stress box (by clicking on the check mark to remove it), the contingency will be applied at the selected point itself (to verify whether the selected contingency causes instability at that point or not). 5. Pull down the Run menu and select Fast Time Domain analysis. Figure 5.3 Running FTD 6. VSAT first creates the specified operating point and then runs the FTD simulation with the specified Switching file. The bottom of FTD window shows the processing steps and the messages from computation engines are displayed in the VSAT Message window under the tab for the selected scenario. Figure 5.4 FTD results 7. The results of the FTD simulation are displayed under the Results tab of the FTD window. The graph under this tab shows the plots of monitored bus voltages (as specified in the FTD Monitor data). By clicking on the break points of each curve, a pop-up label will show the corresponding bus name for that curve. The Details box shows the number of monitored buses that violate the Voltage Drop and Rise criteria (as specified in the FTD Parameter data). The monitored variables are saved in the binary file Powertech Labs Inc. Page 52

58 scenario_id.bin (which can be read by the TSAT program for plotting and tabulating) and the FTD main output (progress report) is saved in the scenario_id.ftd file. 8. You may select a different Operation Point and/or contingency and repeat the FTD simulation. To exit from the FTD window, click on the x button or select the File Close menu item. Powertech Labs Inc. Page 53

59 6 Remedial Action The Remedial Action (RA) module of VSAT finds the best available control action to make an insecure operating point secure. This chapter describes the data requirements and operation of RA. 6.1 RA Data Requirement Two data files are needed for computing the remedial actions: 1. Remedial Control Data: describes the available controls, their priorities, etc. 2. Sensitivity Parameter Data: provides the parameters for the sensitivity-based remedial action computation To select, view and modify these data files for a scenario: 1. Double click on that scenario in the VSAT main window to go to the Scenario window, and in the left section of that window click on Control or Sensitivity Parameter under Remedial Action group (as described in Section 3.2.3). Figure 6.1 Remedial Control view in Scenario window 2. You may examine, modify and save these data files by using the Edit and File menus. The format and meaning of data in these files are described in Sections 9.25 and If you changed a data filename, save the Scenario file by using the File Save (As) Scenario menu and Exit the Scenario window. Powertech Labs Inc. Page 54

60 6.2 Running RA To run the RA module, in the VSAT main window pull-down the Analysis menu and select Remedial Action, or click on the RA button on the tool bar. The Remedial Action window will appear. To run RA, in this window do the following: 1. In the Select Scenario pull-down list, select the desired scenario. 2. If, for example, the operating point at 4200 MW transfer level is insecure in Figure 6.2 Remedial Action window the selected scenario, and you wish to find the remedial action for making this point secure, type 4200 in the Select the Operating Point edit box. To select the base (initial) operating point, if the scenario does not involve a Transfer ( Transfer Analysis = No in the Parameter data) you must type zero (0) in this edit box, otherwise, you must type in the value of transfer's source X at the base point (as shown in the VSAT main window). 3. Pull down the Run menu and select Sensitivity method. (In this version of VSAT, this is the only option.) 4. VSAT first creates the specified operating point and then runs the RA module. The bottom of RA window shows the processing steps and the messages from computation engines are displayed in the VSAT Message window under the tab for the selected scenario. Figure 6.3 Running RA 5. When RA computation is finished, the Results box of the RA window shows the Preventive and Corrective controls for making the selected operating point secure. These results are also saved in the RA results file (scenario_id-ras.rpt). 6. You may type a different value in the Select the Operation Point box and run RA again. 7. To exit from the RA window, click on the x button or select the File Close menu item. Figure 6.4 Remedial Action results Powertech Labs Inc. Page 55

61 7 Distributed Processing Setup VSAT can be configured for distributed processing using a single client (must be a PC running Windows 9x, 2000, NT or XP) and any number of servers (see Sections 2.6 and 2.9). The servers may be PC or Unix machines, but only the PC installation is described here. For other types of servers, please contact Powertech. The client and server computers may be connected either only to each other (a stand-alone network), or to an existing network. 7.1 Stand-alone Network Connection Each PC that is used to run the VSAT Client and/or Server must be equipped with some TCP/IP compatible network interface card and be connected to one another over a valid TCP/IP network (Token Ring, Ethernet, etc). For example, two PCs equipped with Ethernet cards each connected to a central hub would be a valid configuration. The only modification required for using a stand-alone network is that the windows HOSTS file C:\windows\hosts on Windows 95/98 C:\WinNT\system32\drivers\etc\hosts on Windows 2000/NT/XP must be modified to include the mapping of the IP addressees to the Host names for all the machines on the network as shown in the example below. Add server IP addresses and host names here Figure 7.1 Adding IP address and hostname to HOSTS file 7.2 Existing Network Connection VSAT is designed to run on most of the existing TCP/IP capable networks without additional requirements. Simply, install the VSAT Client and/or Server on any PC on the network that you intend to use for running Powertech Labs Inc. Page 56