Towards on-line voltage stability assessment using synchrophasors

Advances in technology has made possible the online monitoring and assessment of voltage stability. Synchrophasors measure voltage and current phasors with accurate time stamping with respect to Global Positioning System (GPS) clock reference. A novel voltage stability prediction algorithm using synchrophasors is proposed. Synchrophasor data is used to perform a fast state estimation of the system. This is a departure from conventional SCADA-based state estimation. The traditional method of VQ analysis for voltage stability is put to use in this algorithm to estimate the voltage stability margin. Since the data refresh rate is faster with synchrophasor data than SCADA-based data, the proposed algorithm is suitable for on-line stability assessment. The algorithm is tested on the CIGRE 10-bus system. The results are validated using the well-known modal analysis method.