ISSUES WITH RETROFIT REQUIREMENTS FOR HVRT

1

CURRENT SITUATION

• WGRs HAVE HAD A CLEAR LIMIT OF 1.1 pu SPECIFIED FOR HVRT IN THE GUIDES

• WGRs ARE NOW BEING DEVELOPED THROUGHOUT ERCOT IN MANY STAGES OF COMPLETION BASED UPON CURRENT STANDARDS

• ERCOT PANHANDLE STUDIES INDICATE CERTAIN CONTINGENCIES CAN RESULT IN VOLTAGE SWINGS EXCEEDING 1.1 pu

2

CURRENT SITUATION

• CURRENTLY DEVELOPERS ARE CONTACTING VENDORS AND PERFORMING STUDIES TO DETERMINE THE ABILITY TO COMPLY WITH HIGHER HVRT REQUIREMENTS

• A NERC HVRT STANDARD (PRC-024) IS BEFORE FERC FOR FINAL APPROVAL; IF APPROVED, PRC-024 ALLOWS FOR A 5 YEAR PHASE IN

3

KEY ISSUES/QUESTIONS

• IT IS NOT CLEAR WHY THE CURRENT HVRT STANDARDS ARE NOT WORKABLE

• DEVELOPERS MAKE SIGNIFICANT COMMITMENTS WELL BEFORE THEY SIGN THE SGIA MAKING UNTIMELY CHANGES COSTLY

• THE COMPLETED TSP FISs IN THE PANHANDLE DO NOT INDICATE ANY VOLTAGE SWING PROBLEMS

4

KEY ISSUES/QUESTIONS

• UNDER WHAT CONDITIONS DO THE STUDIES INDICATE POSSIBLE PROBLEMS

• ARE THE MODELS CORRECT• CHANGES TO STANDARDS MUST BE MADE

WITH ENOUGH LEAD TIME TO ALLOW THE INDUSTRY TO RESPOND EFFICIENTLY

• NEW HVRT STANDARDS APPLIED TO THE POI ARE FAR MORE DEMANDING THAN HVRT STANDARDS APPLIED TO THE TURBINES

5

KEY ISSUES/QUESTIONS

• ANY CHANGES THAT ARE SHOWN TO BE NECESSARY AND EFFICIENT MUST BE PHASED IN (PRC-024 ALLOWS FOR 5 YEARS FOR FULL IMPLEMENTATION)

• IF NEED IS DEMONSTRATED ONLY IN THE PANHANDLE, THEN OTHER AREAS SHOULD NOT BE INCLUDED IN NEW STANDARDS

• IF NEED IS DEMONSTRATED THEN ALL TECHNOLOGIES IN THE PANHANDLE SHOULD BE INCLUDED, NOT JUST WGRs

6

KEY ISSUES/QUESTIONS

• COMPLIANCE EVALUATION CRITERIA NEED TO BE ESTABLISHED WHICH PROVIDE MODELING REQUIREMENTS AND ASSUMPTIONS TO BE USED BY DEVELOPERS/TSPs

• THRESHOLDS OF PANHANDLE DEVELOPMENT NEED TO BE ESTABLISHED WHERE THE HIGH VOLTAGE PROBLEMS FIRST APPEAR

7

WGR PROJECT DEVELOPMENT

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