Wide Area Measurement System Using Synchrophasor Data for Assessment of Power System Stability

Abstract

Materials and Methods: In this work, a model of a MATLAB based PMU using Discrete Fourier Transform (DFT) algorithm is developed and tested under different contingencies. The developed PMU is also evaluated for voltage stability and angle stability in which Voltage Stability Risk Index (VSRI) is evaluated to analyze post-disturbance equilibrium state for the voltage and Real Time Stability Index (RTSI) is formulated to obtain loadability of the power system. Moreover, the low-frequency oscillation identification through the PMUs, for the different events is also presented. newlineXIV newline newlineResults and Discussion: The modeled PMU has been tested with two different bus systems to check the detail performance with almost all the contingencies. From the results of all the said contingencies, it is proved that the modeled PMU has been accurately measuring the current magnitude, voltage magnitude, current phase angle and voltage phase angle as per the standards. Real Time Stability Index (RTSI) is implemented for the rotor angle stability assessment, which is also given the load ability margin for the power system without depending on a detailed system model. The utilization and effectiveness of Voltage Stability Risk Index (VSRI) is validated in WSCC-9 bus test system. VSRI is computed based on the synchrophasor for different contingencies. Hence, the corrective actions such as load curtailment may be initiated in well advance. Furthermore, the low-frequency oscillations are detected at the earlier stage of the contingencies with the use of modeled PMU. newlineConclusion: With the extensive case studies, it is proved that the Phasor Measurement Unit (PMU) with the synchrophasor technology in Wide Area Measurement System (WAMS) gives the real-time assessments of the power system stability.