On-Line Voltage Stability Monitoring Of Large Power Systems

An on-line tool developed for voltage stability analysis and enhancement (VSA&E) of large-scale power systems is presented in this paper. The tool has several major functions related to voltage security assessment, load margin calculations, contingency analysis, fast identification of insecure contingencies and critical contingencies, development of preventive control against insecure contingencies and development of enhancement control for increasing load margins for critical contingencies. The parallel version of this tool currently handles on-line models of 20-000 buses with the contingency list in the order of thousand. Some analytical results behind this tool are described.