变电站开关操作对二次就地设备的电磁骚扰特性分析

摘要

变电站中隔离开关操作过程产生的瞬态电磁场是变电站中重要的电磁干扰源之一.瞬态电磁骚扰影响二次测量回路的运行,导致继电保护误动或损坏.结合高压开关击穿过程,分析隔离开关和断路器操作产生电磁骚扰的特性,建立多重节点的传输线电压响应模型及隔离开关电弧分析模型,对电网模型参量进行数值计算,全面评估过电压和过电流特征水平.仿真结果表明,变电站开关操作过程中,母线电流由一系列锥形衰减振荡波组成,隔离开关与断路器之间跳变的阶梯波产生对地电压最大值,骚扰信号频率特性取决于母线和短线的长度.%The transient electromagnetic field generated by isolation switch's operation is one of the important sources of electromagnetic interference in intelligent substation.Transient electromagnetic interferences affect the reliability of the secondary side circuit,and lead to electrical relay protection misoperation or damage.Based on the breakdown process,this paper analyzed the characteristics of the electromagnetic disturbance caused by the isolation switch and circuit breaker operation.Analysis models of multi-nodes transmit line voltage response and switching arc were built up.Through the numerical calculation of power network model,characteristics of overvoltage and over-current were evaluated synthetically.The simulation results demonstrate that the bus current consists of a series of tapered attenuating oscillating waves during the operation of the substation switch,and a step-up transition between the disconnector,the circuit breaker produces a maximum voltage to ground,and the frequency characteristic of the disturbance signal depends on the length of the bus and stub.