计及系统不对称的谐振接地系统故障点残流测算方法

A method of calculating residual current at fault points in resonant grounding system considering system asymmetry

在谐振接地系统中,故障点残流的测算对于故障风险防范等运维工作具有指导意义。针对计及系统不对称的谐振接地系统单相接地故障,首先,分析了正常运行状态和接地故障运行状态的中性点电气量关系,分析表明故障点残流为故障前后的母线零序电压在系统零序总导纳上产生的电流差;然后,结合由逐差法计算得出的系统对地参数及母线零序电压等数据,提出一种故障点残流测算方法;最后,通过MATLAB/Simulink仿真验证,表明该方法基本不受过渡电阻的影响,且测算结果准确性较高。

In the resonant grounding system,calculation of residual current of grounding point has guiding significance for prevention of fault risk and other maintenance works.Aiming at the single-phase grounding fault of the resonant grounding system considering the system asymmetry,this paper firstly analyzes the neutral point electrical quantity relation between normal operation state and grounding fault state.The analysis shows that the residual current of fault point is the current difference produced by the bus zero-sequence voltage before and after the fault on the total zero-sequence admittance of the system.Then according to the system grounding parameter calculated by successive difference method and bus zero-sequence voltage,a method of calculating the residual current of fault point is proposed.MATLAB/Simulink simulation show that the method is basically not affected by transition resistance,and it has higher calculation accuracy.