Siemens Experience with Plant Level Control Modeling

Transcription

1 1 Siemens Experience with Plant Level Control Modeling 14PESGM0540 Yuriy Kazachkov Joergen Nygaard Nielsen Robert J. Nelson Jay Senthil July 30 th, 2014 IEEE PES GM Washington DC

2 Conceptual Diagram Showing Participants of the Plant Vlt Voltage Control 2 Plant Voltage Controller POI Transformer LTC MV On-Grid SVC Local Voltage Controllers

3 3 Wind Plant Voltage Controller with no System SVC Voltage control mode with a droop of 1 to 6%. Siemens default droop value is 4% typical for overseas project (UK) Voltage control mode with zero droop but with the dead band of 0.5 to 2%

4 4 Example of coordination between PVC and SVC To avoid fighting g between the SVC and the PVC, the latter cannot operate at zero slope but will rather operate with a slope setting of 0.5% to 1% SVC on continuous control provides inductive reactive power at voltage levels above 103% system voltage by staying on the slope up to its inductive limit. At and below 103% system voltage, there is no contribution of reactive power from the SVC until the voltage falls to 97% system voltage, and then the maximum capacitive output will be injected into the network. (Example is from a specific project. In most cases PVC should regulate lt 1 p.u. voltage).

5 Generic Wind Farm Voltage Controller 5

6 The PSS E Model for the Siemens Generic Wind Farm Vlt Voltage Controller Three control paths: PCC voltage, Reactive power, and Power factor 6 Inputs PCC voltage, power and reactive power enter the delay blocks emulating communication lines from measuring sensors to controllers. The output of the controller Uwt_Ref is formed from the delayed output of a PI controller of the selected control path. Central voltage controller broadcastsnew references to the turbines every 150 ms. At initialization, voltage reference Uwt_Ref is calculated as an average terminal voltage of all supervised WTGs. Averaging causes some initial movement of local WTG controllers if initial terminal voltages (load flow) of WTGs are different. Takes about 6 seconds for the system to resettle. 10 seconds is normally ample time preceding a disturbance for a dynamic simulation.

7 Examples of commissioning tests of the Siemens voltage plant controllers 1 7 This plot was derived in the course of commissioning tests at the plant with a very weak interconnection (SCR was about 1.35). The red is the set point voltage, the blue is the actual voltage. The weak system insures good control of voltage, despite a 4% reactive droop setting.

8 Examples of commissioning tests of the Siemens voltage plant controllers 2 8 This is typical for the UK applications. Tap position of the POI transformer was changed in a multi step pattern. The plant controller was trying to regulate the POI voltage on a 4% droop line. One can see the POI voltage (red) and the reactive power response (green).

9 Examples of commissioning tests of the Siemens voltage plant controllers 3 9 This test was performed at a relatively small wind farm connected to a strong system in the U.S. Voltage reference (red) was changed step wise. The command to local controls followed this change (blue). However the voltage of the strong interconnection (green) was relatively insensitive to plant reactive output.

10 SWT4: Generic PSS E Model for Siemens Wind Turbine Series 1 10 Includes: Converter Module Electrical Control Module Voltage Plant Controller supervising up to 50 WTGs Frequency Plant Controller supervising up to 50 WTGs (in progress)

11 SWT4: Generic PSS E Model for Siemens Wind Turbine Series 2 11 The model was tested for the system with 4 aggregated WTG units.

12 SWT4: Generic PSS E Model for Siemens Wind Turbine Series 3 12 PCC Voltage (blue) and a Command to Local Controls (red) Reactive Power of Each of Four Units as a Response to Step Change in GWFVC Voltage Reference

13 Conversion of the Plant Controller Model of the Renewable Energy Generic Standard dmodel to Multi Unit Application 1 The standard Generic Renewable Plant Control Model REPCAU1 is designed to interact with the local control of the single equivalent (aggregated) unit. Its block diagram shows two paths, one controlling a WTG active power and another controlling a WTG reactive power. Pref and Qref1 are respective commands from the PlantControllers to local controllers. 13

14 Conversion of the Plant Controller Model of the Renewable Energy Generic Standard Model to Multi Unit Application 2 14 The REPCAU1 standard model has been upgraded with the capability to supervise multiple (up to 150) WTGs, typical for modern wind plants. The dynamics of the standard model were left intact [5]. The upgraded model has a provision for identifying active WTGs supervised by the Plant Controller. At initialization, the Plant Controller collects the active and reactive power outputs of all on line WTGs, sums them up to get the total WTGs active and reactive power and divide them by a number of on line WTGs to calculate the initial average WTG active and reactive powers. These quantities will be used to initialize the state variables of active and reactive power paths of the Plant Controller.

15 Conversion of the Plant Controller Model of the Renewable Energy Generic Standard dmodel to Multi Unit Application 3 15 Simultaneously, the Plant Controller model stores the differences between initial average and initial active and reactive powers for each WTG. In the course of the dynamic simulation the outputs of both paths change depending on a disturbance and have to be transferred to local WTGs controllers as respective active and reactive power commands. To avoid initial movement, at eachintegration step these commandsaresummedare summed up with the stored differences between initial average and initial active and reactive powers for each WTG.

16 16 The updated REPCMU1 plant controller

17 Test system with 10 WTGs supervised by a Plant Controller 17

18 18 No PVC, +2% Step in System Voltage System voltage (black) change is followed by POI voltage change (red). The WTG voltage (blue) is kept constant by local control. POI reactive power flow (pink) drops as a consequence of the local controls action.

19 Documentation of the Upgraded REPCMU1 Renewable Energy Plant Controller Model 19 MISC OTHER MODELS Model lrepcmu1 Model linstance 1: I C O N S C O N S ST A T E S V A R S Tfltr Kp Ki Tft Tfv Vfrz Rc Xc Kc emax emin dbd1 dbd2 QMAX QMIN Kpg Kig tp fdbd1 fdbd2 femax femin Pmax Pmin Tg Ddn Dup VCFlag: 1 RefFlag: 1 Ffag: 0 WTG BUS # MID WTG BUS # MID WTG BUS # MID 1 ' 1 ' 2 ' 1 ' 3 ' 1 ' 4 ' 1 ' 0 ' 1 ' 0 ' 1 ' 0 ' 1 ' 0 ' 1 ' 0 ' 1 ' 0 ' 1 ' 0 ' 1 ' 0 ' 1 ' 0 ' 1 ' 0 ' 1 ' 0 ' 1 '... 0 ' 1 ' 0 ' 1 ' 0 ' 1 ' 0 ' 1 ' 0 ' 1 ' 0 ' 1 ' Bus Number for Voltage Control (if 0 local control): 100 Branch FROM bus number: 30 TO bus number: 100 Branch circuit ID: T1

20 Testing of the Upgraded REPCMU1 Renewable Energy Plant Controller Model 1 20 POI Voltage (red) and Command from the Plant Controller (blue) as a Response to Step Wise Change in Plant Controller Voltage Reference (black)

21 Testing of the Upgraded REPCMU1 Renewable Energy Plant Controller Model 2 21 WTGs Active Powers as a Response to Step Wise Change in Plant WTGs Active Powers as a Response to Step Wise Change in Plant Controller Frequency Reference (black)

22 22 with PVC, +2% Step in System Voltage System voltage (black) jumps up by 2%. POI voltage (red) stays constant due to PVC. Local WTG voltage (blue) drops following the command from the PVC to local controllers. The POI reactive power flow (pink) drops to accommodate change in local voltages.

23 PVC with Line Drop Compensation, +2% in System Vlt Voltage V100 vs Q Xc= V100 V100 vs Q Xc= V100

24 24 PVC and the System SVC Sfault=1200 MVA PVC here SVC here Continuously controlled SVC is simulated by the standard d SVSMO1U2 model

25 PVC and System SVC, +2% in System Voltage Droops of both thpvc and SVC =0 25 QSVC recovers because VPOI is the same as initially Voltages of POI and SVC bus get back

26 PVC and System SVC, +2% in System Voltage Line drop compensation of PVC XC=4%, SVC droop=4% 26 Because V100 increased SVC output drops Voltages of POI and SVC bus increased

27 27 References 1. Wind Power in Power System, p.s, 2nd Edition, Edited by Thomas Ackerman, Wiley, 2012, section WECC Wind Power Plant Dynamic Modeling Guide, prepared by WECC Renewable Energy Modelling Task Force, March 2014, Draft 3. WECC PV Power Plant Dynamic Modeling Guide, prepared by WECC Renewable Energy Modelling Task Force, April 2014, Draft 4. Comparison of WPP models in IEC CDV and WECC. Generic block structure of WPP, presented by Poul Ejnar Sorensen, Technical University of Denmark, Feldkirch, Denmark, Pouyan Pourbeik, Model Specifications and Testing for the 2 nd Generation Wind Turbine Generator Models, WECC REMTF Workshop, Salt Lake City, UT, June 2014

28 28 Acknowledgment Authors acknowledge financial support from Sandia National Laboratory in conversion of the plant controller model of the renewable energy generic standard model to multi unit unit application