由于电力系统是强非线性时变系统,而传统的用戴维南等值参数评估系统电压稳定性的方法在具有动态特征的非线性电力系统应用上有很大局限性.基于非解析复变电力系统的动态分析方法,提出了评价N-1系统PQ节点电压稳定性的法向阻抗模裕度指标,并由此指标来判定N-1网络中电压稳定最薄弱的环节.另外,法向阻抗模裕度最小值决定系统电压稳定整体水平,通过开断标准IEEE14节点系统中的重要支路,计算出支路开断后PQ节点法向阻抗模裕度最小值.然后通过对比开断不同支路时对应的最小法向阻抗模裕度值,找出系统电压稳定性最弱时的开断支路,并将此支路视为关键支路重点监控,从而为电力系统的规划和调度提供参考.仿真结果验证了此方法的正确性和有效性.%Power system is a strongly nonlinear time-varying system, while it has large limitation when using traditional method such as Thevenin equivalent parameters to evaluate system voltage stability of nonlinear power system with dynamic feature. Based on dynamic analysis method of non-analytical complex power system, this paper puts forward normal impedance modulus margin index to access the N-1 system PQ node voltage stability, and uses the index to assess the node voltage stability weakest level of N-1 network. In addition, the minimum normal impedance margin value determines overall level of the system voltage stability, through opening important branches of the standard IEEE14 nodes system, it calculates the nodes minimum normal impedance modulus margin after branches opened. Then it compares this minimum normal impedance modulus margin values to find out the corresponding opened branch when the system voltage stability is weakest, and thinks this branch as key branch, so as to provide reference for power system planning and scheduling. The simulation results verify the correctness and effectiveness of this method.
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