PRESENTATION OF RESULTSFROM THEINTERIM REPORTNEW ENGLAND OSCILLATION STUDY
AGENDA BACKGROUND STUDY OBJECTIVES SCOPE OF STUDY RESULTS FROM INTERIM REPORT NEXT STEPS COMMENTS/QUESTIONS
BACKGROUND Poorly damped oscillations have been observed in computer simulations of the NE system. The uncontrolled damping of these oscillatory modes could become unacceptable under certain conditions. Past example of low frequency unstable oscillations: WSCC blackout in Western US (August 10, 1996) – cascading outages. Power System Stabilizers (PSS)s are cost-effective way of improving stability. Provide opportunity to improve system model. Address compliance issues.
STUDY OBJECTIVES Identify critical oscillatory modes in the NE system. Determine the generating units that will be most effective in controlling these oscillatory modes. Recommend settings for the exciters/or PSSs. Provide performance verification for the recommended settings.
SCOPE OF STUDY PART 1 Evaluation of Exciter Step Response Analysis of Oscillatory modes Determination of Power Plants for Control Tuning Interim Report PART 2 Exciter and PSS Tuning Verification Testing Part 3 Additional Simulations Final Report
SUMMARY OF RESULTS FROM INTERIM REPORT EVALUATION OF EXCITER STEP RESPONSE 12 exciters were flagged for follow-up action due to questionable values of certain exciter parameters.
ANALYSIS OF OSCILLATORY MODES LOCAL OSCILLATIONS WITHIN ISO-NE No unstable modes found; but some poorly damped. Recommendations included verifying exciter models and possibly adding PSSs to several units. INTER AREA OSCILLATIONS INVOLVING ISO-NE Five modes were identified with low damping along with generating units participating in oscillations.
DETERMINATION OF POWER PLANTS FOR CONTROL TUNING Study recommended general model/parameter review on 32 units. PSS SITE ADDITIONS 13 units were recommended as candidates for PSS addition.
NEXT STEPS Start Part 2: Exciter and PSS Tuning, and Verification. Initiate update of exciter and PSS models with generator owners.