On-Line Monitoring Of Voltage Stability Based On Wide-Area Measurement System

In recent years, several accidents of voltage instability or collapse took place in the world. At the same time, the entrance of big system, high voltage, big generator, long-distance transmission leads power system face more voltage stability threat in our country. With the modern power system extended ceaselessly and the complicate dynamic characteristic , the on-line monitor of voltage stability from the whole view becomes more and more important. The rapid development and wide applications of Wide-Area Measurement System (WAMS) provide great potential for online assessment of voltage stability in large-scale power systems.Based on the absorbing of previous work and the understanding of the WAMS principle, this dissertation conducts concentrated research work on on-line monitoring of the voaltage stability, such as on-line voltage stability index according to the synchronous phasor measurements and voaltage stability on-line monitoring system based on WAMS.An on-line voltage stability index, LVSI, has been proposed in this paper, which is defined as a function of measurements of WAMS. For any transmission line at a certain time point, LVSI is constructed based on the model of aΠequivalent connecting with an infinite voltage source and a load. Simulation results of the EPRI 36-bus system show the validity of the index.Utilizing program language of Visual C++ 6.0, a on-line monitoring system of voltage stability,using the LVSI as the main index, is developed for the need to expanded the WAMS center function. Currently, each module codes of the system have been carried out and run steadily as a whole, the test with simulation attains anticipant result.