SPECIAL REPORT FOR STUDY COMMITTEE B5 (Protection and Automation)

Transcription

1 100 Study Committee B5 Colloquium SPECIAL REPORT FOR STUDY COMMITTEE B5 (Protection and Automation) PS1: Acceptance, Commissioning and Field Testing for Protection and Automation Systems Marco Antonio M. RODRIGUES (Brazil) SUMMARY This special report reviews 26 papers submitted by authors from 20 countries as contributions to the Preferential Subject 1 of the 2013 SC B5 Colloquium - Acceptance, Commissioning and Field Testing for Protection and Automation Systems. The papers provide a quite diverse overview of the subject, ranging from practical experiences in testing modern protection and automation systems, going through engineering and design techniques to improve system testability to the development of special test systems like digital simulators. To aid the discussions, the main topics addressed by the contributions were grouped into five themes, namely: Experiences and Improvements in testing modern protection and automation systems. Engineering and design techniques to improve testability of protection and automation systems. Test procedures during protection and automation systems life-cycle. Testing of specific functions or devices in protection and automation systems. Special techniques for testing of protection and automation functions and devices. Twelve questions are raised to facilitate a focused discussion on the subject after a brief summary of each theme and of each paper included in that theme. Keywords Power System Protection and Automation systems, acceptance tests, field tests, IEC INTRODUCTION Testing of Protection, Control and Automation devices and systems is a very broad area, unsuspectedly full of specificities that are difficult to be completely covered. Testing activities begin at the design phase, where IED specifications should be verified against existing requirements. When the specific hardware and software are assembled together a myriad of type tests need to be accomplished by the manufacturer in order to assure the expected product quality, encompassing not only the device functionality but also its suitability to the harsh substation environment. A given product also has a life-cycle resulting from a number of upgrades or patches, usually in the device s embedded software (firmware). Such changes force retesting protection and automation devices. In fact, with the functional interoperability of modern IEC devices, tests may need to be extended to other devices, even if their components were not changed. 1

2 A similar situation exists for an entire Protection, Control and Automation Systems (PCAS). PCAS requirements are the first thing to be prepared and validated: the effectiveness of this validation is an important key to avoid delays and repetitions of the next phases. After that stage a specific system design should be developed and tested for adherence to the initial requirements. At this step, simulation of the power system and of the PCAS devices is an important tool used for better understanding of the system s limitations and features. Once the system design is qualified, the system integrator or manufacturer prepares an assembling of the physical system, providing all the necessary features to perform the Factory and Acceptance Test (FAT). The FAT coverage is a very involving discussion as it shall balance between the cost and duration of the FAT and the SAT, Site Acceptance Tests. When postponing a given test procedure to the SAT, it will probably be performed in a more tight time frame and with all the system deployed and connected. SAT is the last phase of the system commissioning, prior to the plant production stage, and encompass additionally, the operation of analog (voltage and current instrument transforms or other nonconventional instrument transforms, temperature etc.) and digital (state acquisition) transducers, control connections from PCAS to primary equipment and communication connections to other substations (such as those used for schemes based on teleprotection and transfer trip) or to a superior hierarchical level. However, PCAS life-cycle does not end at this stage. Changes are made to the system due to malfunctions in PCAS devices and due to power system reconfiguration and expansion, which raises the necessity of changing hardware and software parts, raising the need for a complete or partial repetition of the tests performed in the previous phases. Testing also may occur in a periodic or predictive way, where the PCAS is retested even if no change occurs. In both cases the testing is complicated by the fact that, in general, the installation cannot be isolated from the power system, and the PCAS has to be tested in parts so that the necessary PCA functions are available. A number of strategies are discussed for increasing the tests performance and reliability in these situations. Good engineering practices and adequate documentation is another key for efficient and effective testing. Planning test from scratch may become very useful in a number of situations. Adherence to published standards may also be an enabler for a large number of automated test and verification procedures, conferring more reliability to PCAS. The reader should be warned that many concepts concerning testing of complex systems are named differently through the many papers presented to PS1, as well as most of the technical literature. This report has tried to follow the terminology used in the WG B EXPERIENCES AND IMPROVEMENTS IN TESTING MODERN PROTECTION AND AUTOMATION SYSTEMS The four papers under this first theme address practical experiences in testing PCAS, with contributions aiming at improving the efficiency of the test process. Summaries 2

3 Paper 110, Commissioning Testing for Protection Systems in Japan, focuses on the on-site tests done as part of maintenance/operation activity for the protection system and describes the methods which have realized an efficiency improvement and a cost reduction on various types of testing which are carried out before the protection system are put in operation. It also shows specific examples found in the actual power systems, hanging from a bus bar protection system to two wide-area SPS, including the situation of a multi-vendor configuration. Paper 113, Testing experiences with protection devices and systems - different practice approaches in Germany, gives an overview of the test scope and activities of protection devices and systems and their cooperation with the switchgear peripherals from the perspective of the German network operators. It encompass not only the FAT and SAT test documentation, but also general corporate philosophies for device testing cycles, considering the gradual replacement of electromechanical and static devices for digital technology. Paper 115, Testing Protection and Automation Systems in Romanian Power Grid, presents some lessons learnt regarding configuration and testing of a renewal in the PCAS protection system in a EHV substation connected to 440 kv overhead transmission lines. Aspects regarding organization and coordination of commissioning tests are highlighted. Test in protection IEDs are detailed, not only in functions like distance protection and instantaneous overcurrent protection, but also tests of logic circuits, testing of the tripping logic and others. Paper 119, Strategies and Procedures for Site Acceptance Tests of IEC Based Systems, presents important lessons that have been learned from IEC based SAS new applications in more than 30 high voltage substations at Companhia Hidro Elétrica do São Francisco, Brazil, in the last 5 years. Practical applications provide useful tips and help build testing guidelines, including the issue of network communication testing procedures considering topologies and redundancy. The paper cites the use of some of the results arising from CIGRE WG B5-32 ( Functional Testing of IEC Based Systems ) in the utility. Questions 1.1. Modern PCAS requirement drawing, design, implementation and commissioning processes are more complex than those for previous PCAS generations. Such complexity comes for many reasons such as the use of multifunctional IEDs, distributed functions design and multi-vendor solutions. Also there is a need for integrating already deployed devices to new ones embedding modern technologies. What are the experiences concerning the distribution of individual test procedures among the complete testing chain stages (type tests, qualification tests, FAT and SAT)? 1.2. In modern IEC automation implementations every piece of action depends on the network availability, performance and (cyber)security. The effort for testing network related issues cannot be disregarded in the overall test procedure. What are the specific tests applied to the communications network of a PCAS? 3. ENGINEERING AND DESIGN TECHNIQUES TO IMPROVE TESTABILITY OF PROTECTION AND AUTOMATION SYSTEMS 3

4 The seven contributions under this theme present philosophies of design, engineering and testing that can cope with the complexity of modern PCAS. Instead of suffering from problems that may arise at the final stages of a PCAS deployment, the contributions focus in addressing them at earlier stages. Also, the use of the appropriate testing tools as a key factor in the success of testing procedures is addressed. Summaries Paper 101, Collaboration Leads to Modular Protection and Control Solutions That Satisfy IEC Security and Dependability Requirements, from USA and Brazil, highlights the advantage of collaboration and frequent, uninhibited, dialogue among product software and hardware development, manufacturing, panel design and construction, PCM and ICT design and configuration, and site construction and installation teams. It claims that modern PCAS systems depend on efficient best practices during the frontend engineering and design phase. Paper 106, Improving the Efficiency of Testing of Protection Devices and Systems, from USA, remembers that although the use of advanced testing tools is a key factor in testing modern PCAS, it is also important to keep in mind that a good understanding of the test objectives as well as of the testing tools is fundamental to achieve both effectiveness and efficiency. The author exemplifies this reasoning with a number of distinct cases, ranging from tests in need of high synchronization precision, like those of PMU systems and of distance protection for double circuit lines, to the test of GOOSE based protection systems. Paper 108, A New Approach for Test in Substation with Entire Application of IEC including the Process Bus, from Brazil, discuss the tests requirements that imposed tough paradigms rupture occurring on substations projects due to application of IEC 61850, traces the main needs and changes that exists for IEC PCAS and points out the requirements of a new test tool, considering the use of process bus, network redundancy and distributed functions. Paper 114, Testing of IEC61850 Process Bus Based Substation, from Canada, describes the design and test methodologies used during the FAT and SAT for an IEC61850 based transformer station pilot project. It goes into details concerning the test of the station bus using tools developed for easy IED isolation and for GOOSE message monitoring. It concludes asking manufacturers for a more interoperable implementation of the test related features detailed in edition 2 of the IEC standard and for better testing tools. Paper 117, The Advent of System Engineering Tools and the Impact on Functional Testing of Distributed Systems based on IEC and Modern IEDs, from Portugal, explores how system models and advanced system tools may enable highperformance testing in the several test stages (process-bay, bay-station, station-remote and process-remote) by automating, integrating tools and streamlining a process which is performed mainly manually today. Authors also explore the extent of how IEC and related work may enable multi-vendor testing in the future. Paper 124, Testing Distributed Functions, from Brazil, analyses the strengths and weaknesses of testing separately an IED or testing several IEDs together, considering an installation comprised of IEC compatible devices with distributed functions. 4

5 An example is given showing that, although individual tests are not always avoidable, the cost of integrated tests is less expensive and the result more reliable. Paper 125, Certification, acceptance and commissioning testing practices return on experience to date from WG B5.45, details the preliminary findings of ongoing CIGRE WG (B5.45) regarding the engineering process required to manage certification, factory acceptance and commissioning testing during a protection and control project. The role of standardization and the importance of using modern tools and test equipment on dedicated platforms are stressed. The test of a distance protection, separating accuracy from dynamic performance tests, is given as an example. Questions 1.3. The efficiency of testing procedures for complex PCAS may increase significantly if the related features embedded in modern PCAS devices as well as a standardized design are used. This is particularly important in the case of multivendor implementations. Another factors determining test efficiency are a comprehensive definition of the system requirements, bearing in mind testing issues during all PCAS lifecycle, and the interaction with manufacturer design personnel during all phases of the project. What are the experiences in improving the efficiency and effectiveness of testing modern PCAS? 1.4. Awareness of all construction details (functionalities, operating principles, internal algorithms, accuracy, communications etc.) of modern PCAS as well as detailed knowledge of testing tools (functionality, characteristics and software) are fundamental when facing the complexity of testing modern PCAS. However, it is important to balance between the effort for preparing test scenarios and training personnel involved in testing with the cost and time to complete the system commissioning. Such balance may impact the comprehensiveness of the test. Are there adequate testing tools for aiding reliable and simplified tests of PCAS covering all testing chain stages (type tests, qualification tests, FAT and SAT)? 1.5. Implementing a sound test procedure and building a dedicated test workbench in the occasion of commissioning a new installation is a very demanding task for protection and automation personnel. There follows a large effort in absorbing the novelties of the technology as well in preparing the test personnel for the task. What are the utilities vision, actions and achievements regarding the preservation of all knowledge developed during commissioning for future use during power system expansion or in maintenance of existing assets? 1.6. Although the IEC standard deeply changed the way PCAS were built, the power industry is absorbing the IEC standard at large steps. However, it is a live and evolving document, which is expected to have new editions from time to time. What has been the evolution in the testing of PCAS with the introduction and evolutions of IEC 61850? 4. TEST PROCEDURES DURING PROTECTION AND AUTOMATION SYSTEMS LIFE-CYCLE Before a PCAS is put into operation, a large number of tests is performed to assure reliability and dependability of entire system. However, the PCAS test cycle has not ended. Periodical testing, replacement of defective or damaged devices and power system reconfiguration or expansion will impact the already deployed PCAS and call 5

6 for new tests. In many cases, this new test round has to be done with part of the PCAS, while the rest of the system operates normally. Papers herein place some light over this issue. Summaries Paper 103, Specific IEC system requirements to facilitate the configuration and maintenance process, from Spain and Brazil, made an in depth analysis of some requirements that can be taken into account to facilitate the subsequent management of the system, searching for features that the users should expect from the software tools. A new range of possibilities to improve the configuration, test and maintenance processes in substation automation systems could be accomplished going a step further in the standardization of the configuration files of IEC devices. Paper 104, Testing Power Automation Systems: Current Practices and Coming Evolutions, from France and Brazil, discusses the tests of Power Automation Systems (at substation or grid level) all over their lifecycle and analyzes opportunities for efficiency improvements in term of system confidence, engineering effort and lead time. The paper highlights new technologies and tools currently being developed to address these requirements, such as rule based decision leveraging of IEC semantics, system virtualization and the use of mobile devices. Paper 107, Version Control and Patch Management of Protection and Automation Systems, from UK and France, details processes for the application of version control and patch management that are applicable to the complete range of secondary substation equipment including but not limited to: protection relays, Ethernet switches, merging units, substation gateways and PC based engineering workstations. Potential technologies that can support these processes are also discussed. Paper 116, Acceptance, Commissioning and Field Testing for Protection and Automation Systems, from Switzerland, describes new challenges and opportunities related to interoperability between compliant IEDs and tools as well as for testing and maintenance processes. The complete life cycle testing sequence is summarized and the impact of IEC to these tests is given. The main highlight is the key role of the System Configuration Description (SCD) file and the importance of the system integrator. Paper 120, Testing of a Digital Substation Based on IEC 61850, from Russia, concentrates on site acceptance tests and periodic tests, listing requirements to the testing of a distributed protection and discussing practical techniques that provide high security of the test procedure and results, particularly when a small part of the SAS is under test and the rest is in normal operation mode. Additionally, improvements to the design of the protection system are suggested in order to increase dependability and stability of the system during testing. Questions 1.7. In many situations, a part of the PCAS needs to be tested without connection to the rest of the system. This is the case of FAT and tests performed after system deployment, such as periodical tests and tests driven by the replacement of a defective IED, the replacement of the IED s firmware or even by a change in the substation configuration. IEC standard has defined a number of features 6

7 to help IED isolation in such cases, but their implementation by manufacturers is recent and its use is still restricted. What are the most usual procedures used when only part of the PCAS is tested? 1.8. In multivendor IEC systems, the configuration files devoted to IED configuration (ICD, CID and IID) may contain configuration data in nonstandardized formats, as cited in paper 103. How acceptant tests of multivendor IEC based systems have been impacted by the use of configuration files containing data in non-standardized formats? 5. TESTING OF SPECIFIC FUNCTIONS OR DEVICES IN PROTECTION AND AUTOMATION SYSTEMS Although testing of a complete PCAS has a plethora of aspects, special consideration must be applied to test specific functions or devices, particularly those impacting protection schemes, supervision data or wide area protection and control. Summaries Paper 102, Power Swing Secondary Testing and Analysis of Transient and Steady State Performance of Protective Relays, from Brazil, presents a methodology for easily reflecting the effect of power system dynamics to the protective relay connected to the test equipment and assert its behavior under power swing phenomena, aiming at a substantial reduction of working hours in FAT and/or SAT. Paper 105, Best Practices for Testing Process Bus Protection and Control Systems, from USA and Canada, describes some best practices for both commissioning and routine testing of process bus systems, based on actual field experience, including discussions of the appropriate methods of commissioning and routine testing. The paper also discusses taking advantage of process bus capabilities for redundant measurements to reduce the need for routine testing, and suggests some new tools that can be developed to simplify process bus testing. Paper 109, Test Functions and Methods for Wide Area Protection Systems, from Japan, describes functions that have been integrated within wide area protection systems together with their respective test methods. Typical systems would be multiterminal current differential protection and special protection schemes (SPS), where IEDs are located at different substations and share information via communication channels. Paper 118, Measurement of Transmission Line Impedance, Ground Factor (K) Determination and Improved Reliability of Distance Protection, from Brazil and USA, presents an advanced method for measuring the transmission line impedance, which makes possible checking against line parameters calculated using a model that considers transmission line geometry, ground resistance and conductor characteristics. Paper 122, Automated testing of power swing blocking relays, from German, presents alternative ways to calculate the voltage and current waveforms at the measuring power swing blocking relay. The first method is based on a simplified network model while the second method is based on the definition of the trajectory in the complex R/X plane. The tests are used to validate relays according to requirements set by a working 7

8 group with all four German transmission system operators in order to harmonize the behavior of distance protection devices in the case of grid power swings. Paper 123, Factory Acceptance Testing of Phasor Measurement Units and Substation Phasor Data Concentrators for the Eskom Wide Area Monitoring System, from UK, South Africa and Brazil, summarizes the test methodology, equipment used and conclusions reached during the FAT of the MiCOM P847 Phasor Measurement Unit and the PhasorPoint Substation Phasor Data Concentrator for use on the Eskom Wide Area Monitoring System. The FAT fully examined the configuration, operation and performance of the devices, the Global Positioning System clock and the substation communication network. Questions 1.9. Multi-terminal transmission line protection as well as Wide Area Protection and Control Systems use communication channels for efficient operation. When it comes to use modern protection devices, implementing inter-station digital network communications, the time synchronization becomes also an important issue in some cases. How are inter-station communications tested, particularly when synchronization dependent protection functions are involved? Process bus is a new paradigm for analog and digital signal acquisition, as well as for delivering of control actions. The use of merging unit has an impact on testing as all the analog and surge protection is located near the process and all communication is performed through a digital network. Testing a merging unit deployment means not only making type tests concerning its accuracy and transient behavior but also testing physical and logical availability of data to all distributed functions in the PCAS. What are the experiences in testing the complete signal acquisition and control chain in type tests, FAT and SAT? Many modern IEDs, particularly those including protective functions, also embed the PMU function. Some utilities are using this feature to obtain synchrophasor data at very low cost (virtually no cost). Has the PMU function, embedded in many already deployed IEDs, been included in type tests or in FAT? 6. SPECIAL TECHNIQUES FOR TESTING OF PROTECTION AND AUTOMATION FUNCTIONS AND DEVICES This sub-theme intends to group papers presenting test facilities and test approaches not regularly used by utilities or which are innovative. This is the case of system simulators, test sets built for automatically testing IEDs during development stages and test procedures using unconventional arrangements. Summaries Paper 111, Qualification and type Tests of Protections at RTE using a Real-Time Simulator, describes the characteristics of the new real time simulator acquired by the French operator, as well as the tests used by Rte for the functional qualification of different types of protections (in particular distance- and differential line protections). The capacity and the interfaces of the new Real-Time Simulator are designed to enable the connection of replica of the control-system of HVDC links, SVC and other FACTS. 8

9 Paper 112, Dynamic testing of transmission line protection as an alternative to real time digital simulators, from Brazil, proposes a testing methodology based on the postprocessing of COMTRADE files generated by digital simulators like ATP/EMTP with presetable time-stamps to meet typical times related to real time events. Test sets are used to inject analog and digital signals into the relays to be tested. The proposal is not the substitution of the RTDS tests but to offer an economical and useful alternative in helping selectivity studies and disturbance analysis. Paper 121, Testing of distributed functions and multi-functional IEDs, from UK and China, describes an Automated Validation Testing set-up assembled for the development of a new multi-function IEDs. In accomplishing the automated validation testing, thousands of cases can be tested within an optimized time period without increasing the burden on project resources. The automated test system can directly simulate the product operation in the field so that any development defect can be reproduced and found more reliably before the product release. Paper 126, FAT testing of concepts, from Australia, presents a Proof of Concept approach, used by a utility to create its first substation, that provides not only a means to develop and change philosophies but also an environment to perform in depth testing of operation and failure modes which would be extremely difficult on site without risking project delays. The simulator has been used not only as a tool for testing, but also to solve design issues in new developments and serve for training operational staff and field testers. Question Simulation is a very important tool used in many situations during test of PCAS. There exist many implementations from complex and expensive simulators fitted for many uses to specially designed simulators suit for specific needs. Smart approaches using off-line simulations for performing dynamic testing were also presented in one paper. Are there new trends concerning the use of simulation tools for PCAS test chain (type tests, FAT and SAT) considering the facilities provided by newer technologies? 7. FINAL REMARKS This special report reviewed 26 papers submitted by authors from 20 countries as contributions to the Preferential Subject 1 of the 2013 SC B5 Colloquium - Acceptance, Commissioning and Field Testing for Protection and Automation Systems. They address a large number of distinct aspects that are of importance to the practice of PCAS testing. The twelve questions raised can testify just a few of them. Among the many topics brought to readers attention, the following are highlighted: An adequate distribution of tests through the entire test chain is an important aspect to reduce duration and cost. The efficiency of testing procedures for complex PCAS may increase significantly if the related features embedded in modern PCAS devices as well as a standardized design are used, particularly in the case of multivendor implementations. The use of adequate testing tools can help in focusing the test team attention to the most important test features, balancing awareness of all construction details of modern PCAS with test cost. 9

10 Testing of communication networks may consider also network specific issues, such as switch configuration and cyber-security. Utilities should care about documentation and training related to test of PCAS, in order to cope more easily with future changes in the system or with any maintenance action required. Adherence to IEC as well as many others standards is an enabling factor for more reliable and repeatable tests, including the possibility of development and use of testing tools and software in multivendor environments. When testing part of a modern PCAS, there are situations in which only part of the system is present and the other need to be simulated or isolated. The choice of the best approach in each test case is still an open issue. Simulation of power system as well of IEDs is becoming a important tool to use in type-tests and FAT, where only a small part of the PCAS is available. 10