Real-time voltage stability monitoring and evaluation using synchorophasors

This paper focuses on evaluating online voltage stability indices for an interconnected power system. The voltage stability indices are measured during the operation of the power system when the dynamic changes take places. The evaluation of the stability and security indices were performed by simulation and measurement of real-time data using Phasor Measurement Units (PMUs). The evaluation of the dynamic voltage stability indices were performed by creating dynamic load step change in both simulation and implementation at the library scale power system testing environment. The developed simulation involved the modeling of transmission line emulators with a pi structure. Monitoring software was developed and implemented for wide area control and monitoring system on the laboratory power system test-bed. The formulation of the various indices includes: fast voltage stability, line stability and load margin in addition to sensitivity of voltage variation to load changes. Simulation results were verified with measured and monitored data. A good agreement was achieved indicates the validity of the implemented procedure.