基于最优化方法的事故后系统分岔点追踪

准确解析事故后电网的小扰动稳定域,对确保电力系统的经济运行具有重要意义。但电网遭遇事故后,其拓扑结构可能发生变化,求取事故后标识小扰动稳定域的分岔指标变得困难。详细比较了追踪分岔点的3种方法:连续法、直接法和最优化方法,讨论了3种方法的适用范畴,比较了它们在求解效率、解质量等方面的差异。针对事故后系统可能不稳定、传统方法无法计算出此时分岔指标的问题,采用最优化方法可以有效地计算出此时的分岔指标,为目前电力系统中受到重大关注的"N-n"问题提供了良好的分析工具。仿真算例表明求得的分岔指标可以有效标识故障的严重程度,可作为一个较好的切负荷指标。

Post-contingency power system bifurcation point tracing based on optimization method

The post-contingency small-signal stability region of power grid is analyzed for its economic operation.However,the topology of power grid may change after contingency,which makes the bifurcation index calculation of small-signal stability region more difficult.Three methods of bifurcation point tracing,continuation,directness and optimization,are compared in computation efficiency and solution quality.When power system suffers post-contingency instability,the optimi-zation method may be used as a powerful tool for "N-n" analysis to effectively calculate the bifur-cation indices,while the general methods may not be useful.Simulation results indicate that the bifurcation indices calculated by the optimization method identify the severity of fault effectively and can be taken as the criterion of load shedding.