With the increased number of phasor measurement units (PMUs) being installed, the problem of utilizing the data for accurate computation of power system stability margin becomes more important. A software tool is needed to compute the exact values of voltage stability margins under any system conditions in planning and real-time environments. The concept of the Region Of Stability Existence (ROSE), demonstrated under this project, provides the framework for utilizing PMU measurements in order to compute this region and operational margins as follows:
- Improve state estimation
- Continuously monitor the electric grid in the real-time environment
- Identify system stability limits
- Alarm the operator about impending crises before a new State Estimator (SE) case arrives
- Invoke optimal remedial actions to prevent a blackout
The ROSE computes a MW/MVAr/MVA index (MW/MVAr/MVA margin on the interfaces or at load pockets) that can be easily understood and interpreted by the operators in order to increase situational awareness. Voltage constraints, thermal limits and steady-state stability are simultaneously monitored during the ROSE analyses. The region is shown on the planes of two phase angles and real powers. The project also demonstrates the effect of the remedial actions on the region. The ROSE approach is illustrated by using the ISO New England’s real-time model, SCADA data and PMU measurements. The study results show that this approach is effective in improving the reliability of the ISO New England's transmission network and may be used for preventing major blackouts.
Keywords: Phasor measurement units (PMUs), voltage stability limit, steady-state stability, optimal remedial actions, region of stability existence, reliability analysis, operational margin.