This use case describes how the use of phasor measurement data could enable SCE to maintain system stability following a system event. SCE currently uses phasor data to evaluate system conditions on a post-mortem basis, following an event. This use case describes the use of phasor data to trigger alarms and provide recommendations for system operator control actions within seconds of a system event. This capability would reduce the likelihood of an event causing widespread catastrophic grid instability.
Phasor data measures the physical characteristics of voltage and current waveforms, including phase angle magnitude and frequency oscillation. If SCE’s Phasor Analysis Application identifies abnormal conditions, it would generate an alarm in EMS and prompt the Contingency Analysis application to calculate recommended actions for the system operator. The system operator would then receive the recommended actions from the Contingency Analysis and take appropriate remedial action. This use of phasor data represents one method within a portfolio of tools to combat system instability, and should be considered within a broader context of intelligent grid control. Other methods of maintaining grid stability that do not utilize phasor data include Centralized Remedial Action Schemes (discussed in use case D15), and other tools that optimize for various system variables such as transmission capacity loss, volt/VAR control, distributed generation dispatch, and renewable resource penetration levels. The benefits of using phasor data for real-time grid monitoring and control include increased system reliability, reduced costs, and increased customer benefits.