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WECC Guideline:

Annual Base Case Compilation and Data Check Scope of Work

Formerly known as the Annual Study Program Scope of Work

Date: March 9, 2017

Introduction

The WECC Annual Study ProgramBase Case Compilation and Data Check Scope of Work consists of two primary activities; (1) the development of steady state and dynamic base case models (base cases) and (2) an annual assessment of Transmission SystemInterconnection-wide model data performance based on selective disturbances simulated using the base cases. The base cases are developed through a joint effort between WECC Staff and various planning and operating entities throughout WECC.

Development of Base Cases

The System Review Working Group (SRWG) is tasked with compiling a set of base cases annually. A Base Case Compilation Schedule is developed to establish timelines and scenarios to model. The Data Preparation Manual defines the process applicable entities follow to compile the base cases. Compilation of base cases consists of three distinct phases.

  1. Initial Data Submittal Phase
  2. Review Phase
  3. Final Approval Phase

Base Case Compilation Schedule

The Base Case Compilation Schedule is drafted by the SRWG. The drafting process includes conducting a survey of TSS and SRWG members to provide input on the desired base case scenarios to be compiled. Results of the survey are discussed during SRWG forums.

The objectives of each annual Base Case Compilation Schedule are:

  1. Provide a detailed schedule, to appropriate stakeholders, identifying necessary data submittals and data review milestones to compile WECC bases cases.
  2. Identify base cases to be compiled. A typical annual base case compilation schedule includes the following base cases:
  3. Five operating cases
  4. Two scenario cases – one case will “stress” the following in a five year rotation:
  5. Idaho/Montana/Wyoming
  6. Colorado/Utah/Northern Nevada
  7. Pacific NW and Canada including the California-Oregon Intertie
  8. California (between Path 15 and West of Colorado River)
  9. Southern Nevada/Arizona/New Mexico
  10. One 5-year summer planning case
  11. One 5-year winter planning case
  12. One 10-year winter planning case
  13. One 10-year summer planning case
  14. Upon completion of the Base Case Compilation Schedule, fulfill the WECC obligation to create Interconnection-wide cases.

Initial Data Submittal Phase

WECC Staff posts a data request letter stating the desired data to be submitted to compile a base case as identified in the present year’s Base Case Compilation Schedule. Applicable entities are required to provide the requested data following the requirements and procedures provided in the Data Preparation Manual.

Review Phase

WECC Staff will utilize the data provided in the initial data submittal phase to compile the desired base case. Upon compilation completion, the following actions will be performed on the base case:

  1. Simulation of Standard Disturbances using steady state and transient stability contingency analysis techniques.
  2. Steady state limit monitoring will be set to 100% of the applicable facility ratings including thermal and voltage ratings, total load and generation dropped, RAS functions, and insolvability.
  3. Transient stability limit monitoring will be set to the applicable criteria defined in TPL-001-WECC-CRT-3.1 and generation loss of synchronism.
  4. Running the data error check routines.

The compiled base case and results from the above actions will be posted for applicable entities to review.

Final Approval Phase

After incorporating data corrections and comments received during the Review Phase, WECC Staff will re-conduct the actions performed in the Review Phase. The final base case, results of the contingency analysis, the results of the data error check will be posted.

Annual AssessmentData Check of Transmission Systemthe Interconnection-wide models

An Annual Study Program Report will be developed annually containing a summary of the base cases compiled since the previous year’s Annual Study Program Report and related contingency analysis results, and data error checks conducted during the Final Approval Phase of each base case. Identified issues discovered by the Annual Study Program will documented in the Annual Study Program Results Log.

Summary of Base Cases Compiled

WECC Staff will document a summary of significant system parameters and metrics for each base case since the previous year’s Annual Study Program Report. The parameters and metrics include data error total trending.

Special Study

The Annual Study Program is intended to facilitate a special study as requested by other WECC committees. A special study would include analysis conducted in addition to the study work already performed for the Annual Study Program. Simulation of the Standard Disturbances on the base cases, including the “stressed” area rotating case, does not constitute a special study.

A special study will utilize base cases compiled from the Base Case Compilation Schedule. Special study requestors should identify the base cases to be used for the study and any desired modifications. If a base case from the Base Case Compilation Schedule does not provided a sufficient starting point for the study, the requestor should participate in the Base Case Compilation Schedule process and help identify the desired base case.

Annual Study Program Results Log

Issues identified from the simulation of the Standard Disturbances on approved WECC base cases will be tracked as an Annual Study Program Results (ASPR) log item. The following describes the general use of the Annual Study Program Results:

  1. The ASPR log will be posted on the WECC website and appended to the Annual Study Program Report.
  2. SRWG will report the ASPR log to TSS, and subsequently TSS to PCC.
  3. ASPR Log item removal
  4. Removal of a log item does not require subcommittee approval.
  5. Corrective actions should be demonstrated.
  6. Informative presentation of log item removals will be provided to TSS and PCC.

Approved By:

Approving Committee, Entity or Person / Date

WESTERN ELECTRICITY COORDINATING COUNCIL •

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