大型电力系统非全相振荡时任意时刻电气量的计算

METHOD FOR CALCULATING ELECTRIC PARAMETERSDURING POWER SYSTEM OSCILLATION CAUSED BY OPEN-CONDUCTOR FAULTS FOR RELAY SETTING AND COORDINATION

提出了一种可快速、精确、方便地计算大型电力系统非全相振荡时任意时刻电气量的实用方法。采用补偿法模拟网络操作和断相口的存在 ,建立起可适应网络操作的大型电力系统非全相振荡时任意时刻电气量的计算模型 ;在各序网计算模型断相口分别注入单位电流 ,求得单位振荡电流产生的任意节点各序电压 ;基于 H型参数的物理意义 ,在计及电网结构影响的条件下 ,导出直接利用原网节点阻抗参数计算正序网断相口开路电压的公式 ,求得断相口各序实际电流 ;根据线性电路的齐性原理 ,得到大型电力系统非全相振荡时任意时刻的电气量。这种计算方法具有可自动适应网络操作、可计及电网结构对非全相振荡的影响、互感线路与无互感线路非全相振荡计算方法统一、互感线路非全相振荡计算无需修改故障所在互感组支路导纳矩阵等特点。文中算法已在大电网零序电流保护整定计算软件中实际应用 ,结果表明 。

According to Thevenin's law,the superposition theorem and the physical meaning of hybrid param eters,an engineering- grade m ethod for calculating electric parameters during power system oscillation caused by open- conductor faults is presented for relay setting and coordination by introducing some fictitious nodes and branches to deal with network structure changes resulted in open- conductor faults.The method has advantages such as:1 being able to consider the influence of network structure on power system oscillation caused by open- conductor faults;2 being able to adaptto network changes in topology caused by adding and/ or removing branches to or from network;3 having the unified calculation m ethod for non- m utual or mutual couple branch faults;4 the calculation,during power system oscillation caused by open- conductor faults on mutual couple line,without modifying the admittance matrix of mutual couple branches;5 being easy to be im plem ented on computer.This method has been used in a production program widely used in power system s in China for relay setting and coordination.The application results show that the calculation precision can meet the needs of relay setting and coordination,and its calculation efficiency can make relay setting and coordination faster.