Analysis On Voltage Stability Of Power System Based On The Load Characteristics

With the development of economy and the increasing social requirements for electrical energy, the load of power system accumulates significantly. In order to ease such situation, the extension of power system capacity is needed. However, it complicates the structure and operation of whole system, and meanwhile put the system to a limit state. Therefore, the power system stability, as a foundation of system security, become extremely important. Obtaining the information of current operation state and preventing the voltage collapse become the focus in such academic area.The ZIP load characteristic model and induction motor model are introduced in this thesis. And analysis on factors which affect the power system voltage stability is given. By the application of continuous power flow method, plugging the ZIP load characteristic model and induction motor model into modified equations, the P-V curve can be obtained. Based on the P-V curve, analysis and summaries about the influence on power system voltage stability margin by the power factor and ZIP load characteristic model are concluded.The weak bus of the power system can be obtained from the P-V curve. Based on this, researches on the load shedding location and the load shedding quantity have done. Finally, a proper strategy of the under voltage load shedding (UVLS) is given. The strategy is simulated with the Simulink platform and the effectiveness of the strategy is verified.