基于同步相量测量的电压稳定指标

针对输电网提出了一种基于同步相量测量信息的电压稳定指标。电力系统可以分解成许多电能传输路径,以传输路径首节点电压与末节点电压在首节点电压上的投影之差与首节点电压的比值作为计算电压稳定与否的指标。该指标根据最弱电能传输路径利用局部电压相量测量信息直接计算得出,避免了复杂的潮流计算。局部电压相量测量数据由相量测量单元PMU提供。基于一种快速有效的PMU配置方法,利用直接测量或间接计算的数据作为此稳定指标计算所需要的电压相量信息。运用图论的基本思想寻找电能最弱传输路径。通过计算电能最弱传输路径的电压稳定指标和系统无功储备情况判断系统电压稳定度,当系统接近不稳定状态时,最弱传输路径的电压稳定指标值趋向于临界值0.5。在IEEE5节点和IEEE30节点系统上的仿真表明了该指标预测系统电压崩溃的有效性和正确性。

Voltage stability index based on synchronized phasor measurement

A voltage stability index based on synchronized phasor measurements is presented for trans- mission systems. Power system can be decoupled into several power transmission paths. The ratio of the voltage-drop projection on the start node voltage in a transmission path to the start node voltage is taken as the voltage stability index of power system, which is calculated directly with the local voltage phasor information and the weakest transmission path, the complex power flow calculation being thus avoided. Based on a fast and effective PMU(Phasor Measurement Unit) placement, phasor information is provided by direct measurement or indirect calculation of PMUs. The weakest transmission path is determined by the graph theory. By calculating the index value of the weakest transmission path, which approaches to 0.5 when system is prone to voltage collapse,and considering the power system reactive power reserve, the voltage stability can be assessed. Simulation results of IEEE 5-bus and IEEE 30-bus networks show its validity in system collapse prediction.