Remedial Action Scheme (RAS) Modeling Value Proposition

Transcription

1 Remedial Action Scheme (RAS) Modeling Value Proposition Modeling SPS and Relay Ad-hoc Task Force of the Technical Studies Subcommittee and WECC Staff Western Electricity Coordinating Council May 2, 2014

2 May 2, Introduction Remedial Action Scheme (RAS) Modeling Value Proposition The purpose of this paper is to provide the WECC Board and the Finance and Audit Committee with background information on recent activities related to RAS modeling and the associated benefits. Recommendation To ensure the reliability of the Western Interconnection, or any other Bulk-Power System, it is critical for entities to have adequate modeling tools so they can perform robust operational and planning studies. Unfortunately, the necessary software capabilities do not exist in all of the most commonly used software programs. Adding RAS and contingency modeling, with a common functionality and format, to both GE and Siemens software is a significant step that will benefit electric system operators and planners throughout North America well into the future. This functionality will ensure data can be shared between entities and provide the ability to perform studies outside of their focus area. Accordingly, WECC is seeking funding in its 2015 Business Plan and Budget to fund modifications to implement this common capability in the GE and the Siemens powerflow programs. Background and Issue Statement The Federal Energy Regulatory Commission (FERC) and North American Electric Reliability Corporation (NERC) issued the Arizona-Southern California Outages on September 8, 2011: Causes and Recommendations (Joint Report) on a disturbance that left 2.7 million customers without power and affected both Arizona and Southern California. The Joint Report included a number of findings; however, from their investigations NERC and FERC concluded that two of the contributing causes were: Entities failing to study and coordinate the effect of protection systems, including RAS, during plausible contingency scenarios; and Entities not adequately considering external contingencies that could impact their systems or internal contingencies that could impact their neighbors systems. In response to the findings and recommendations in the Joint Report, under the direction of the Planning Coordination Committee, the Technical Studies Subcommittee (TSS) organized a task force to investigate these issues. The task force determined that

3 May 2, the primary issue was a lack of data-sharing capability. For entities to share data and enable them to perform adequate studies, powerflow modeling programs need to be modified so they can read and write in a common data file format and have a common ability to simulate contingencies and RAS operations. The task force intends and anticipates that this new common RAS and contingency file format and functionality will replace vendor-software-specific methods so appropriate models can be included in interconnection-wide base-case models and be common to all software platforms. A questionnaire was distributed in 2013 to the Transmission Planners (TP) in the Western Interconnection to identify common transmission planning practices. One of the questions asked TPs to identify the software tools used to perform power flow and stability studies. The pie chart below shows the breakdown of the various tools currently used. As can be seen from the chart, if RAS and contingency capability was shared between GE PSLF, PowerWorld, and Siemens PTI PSS/E, the majority of TPs in the Western Interconnection would have the ability to share RAS and contingency data. Software Packages Used in WECC GE PSLF PTI PSS/E PowerWorld V&R Energy WECC needed to gain an understanding of the RAS present in WECC and which software packages would be most used. WECC staff used knowledge of the software package primarily used by each of the RAS owners to create another chart showing the amount of RAS that will be represented in each software program. It should be noted that many entities license multiple programs. Only the program understood to be primarily used was examined.

4 May 2, Number of RAS by Software Package PSLF PSS/E PowerWorld As a first step to modifying vendor programs, WECC contracted PowerWorld to create a common data file format for RAS and contingency modeling. PowerWorld already had most of the needed functionality in place in its power flow program, making it highly efficient for them to perform this first step. PowerWorld has since completed this work and provided WECC with a shared file format that can be implemented into software programs provided by other vendors as they also implement the necessary common functionality. WECC has provided the aforementioned file format and functionality definition to the vendors of the other two most commonly used modeling software programs in the Western Interconnection, GE and Siemens. To implement these capabilities in the GE and Siemens software programs, WECC estimates it will cost approximately $2,000,000 over the next three years. In 2014, $300,000 of the WECC budget is being applied to this work, $1,300,000 is being requested in the 2015 Business Plan and Budget, and any remaining work (including dynamic simulation capability) will be addressed in the 2016 Business Plan and Budget. Having the cost of these enhancements spread over a three-year budget cycle strikes a balance between allowing the program vendors the appropriate amount of time to incorporate the needed changes, spreading the cost across multiple budget cycles, and considering the urgency behind addressing the recommendations from the Joint Report.

5 May 2, Interim Measures It is anticipated that data collection to populate the RAS models will not occur until late 2015 or sometime in In the meantime, the WECC TSS has requested that all RAS models be submitted in the file format that is used by the RAS owner. Although this makes it difficult, if not impossible, for neighboring entities using different powerflow programs to use these models, it does raise awareness of the number and magnitude of RAS on neighboring systems and serves as a starting point for RAS model coordination. These interim models are available on the WECC website from the TSS page (users must be logged in to access the base case files).