典型电力系统模型的双参数分岔分析

针对一个典型的电力系统模型，综合考虑了负荷节点的有功和无功率荷对电压稳定的影响，对模型进行了双参数分岔分析，求得到了参数空间中的鞍节点分岔曲线和霍普夫分岔曲线。结果表明，在有功负荷水平较低时，系统在达到ＳＮＢ点之前会首先遇到ＨＢ点，因此系统会出现振荡失稳；随有功负荷的增国ＨＢ曲线将达到极限点；如果有功负荷继续增加，则ＨＢ点将会消失，电压骨溃将发生在ＳＮＢ点处。并且通过计算Ｌｙａｐｕｎｏｖ指数到了系

TWO-PARAMETER BIFURCATION ANALYSIS ON A TYPICAL POWER SYSTEM MODEL

Bifurcation analysis is performed on a typical power system model with both the active and reactive power (P and Q ) demands at load bus chosen as parameters. Curves of saddle-node bifurcation (SNB) and Hopf bifurcation (HB) in parameter space are calculated. which show that a HB point will be reached before a SNB point with the increase in the demand of reactive power at low active power loading level. As a result. the system will exhibit oscillation and lose its stability induced by HB. A further increase in active power load demand, the two branches of HB curve will join together and arrive at the extremum point. After the extremum point, HB points disappear and voltage collapse will happen at the SNB point. Lyapunov exponents are calculated to obtain stability property in parameter space, the P-Q plane. Results show that SNB curve is the approximate boundary of stable and unstable regions, and the region compassed by HB curves has very complex structure. Considering the effect of load modeling on voltage stability. it is not proper to take into account only the existence of solutions of power flow equations, but the physical mechanism and control strategies of Hopf bifurcation are worthy of further studies. This project is supported by National Key Basic Research Special Fund of China (No. G1998020307) and Ph. D. Program Research Fund of National Education Department of China (No. 1999000354).