电抗耦合与不同期合闸对10kV并联电容器组合闸暂态的影响分析

Influence of Reactor Coupling and Asynchronous Closing on Transition Process of Closing Shunt Capacitors in 10 kV Power System

重庆市电力公司变电站近年来多次出现10 kV系统并联补偿电容器组合装置合闸过程中断路器(柜)故障事件。笔者从实际安装运行条件对合闸的过渡过程进行深入的理论分析:建立了1个含耦合电感的三相二阶电路模型,对该电路进行等效解耦和Laplace变换及反变换,分析了电感之间存在不对称耦合电感对三相电路过渡过程的影响;建立了含对地电容的电路合闸的电路模型,分析三相断路器合闸的不同期对合闸过渡过程中电流和电压的影响;再利用ATP-EMTP电磁暂态仿真软件,代入实际参数对该模型进行仿真计算:比较不同耦合电感情形下的过渡过程;比较同期和不同期两种情形,得出不同期的间隔时间、电容和电感值等因素是怎样影响过渡过程的;在综合比较各个因素综合影响下的电压和电流变化,提出合闸时断路器故障与过电流和过电压相关的结论。

To find out the reasons of the explosion of breakers while putting shunt compensation capacitor into operation in 10 kV power system, transition process of closing has been studied and discussed in depth in this paper. A new circuit model containing three-phase coupled inductors is established to analyze overvoltage and overcurrent in the transition of closing three-phase circuit breaker. Through decoupling and Laplace and inversely transforming the circuit, the influence of mutual inductance and different inductor polarities on the process of transition is discussed. In this paper, a new circuit model is established to analyze the over-voltage and overcurrent while breakers asynchronous closing. By selecting a set of practical operation 10 kV system parameters and taking numerical solution to it, cause of the higher overvohage and overcurrent in the transition of asynchronously closing is investigated. ATP-EMTP Power System Simulation Software is employed into calculating the overvoltage and overcurrent with the actual parameters, the transition process under different situation of decoupling and breakers asynchronous closing is contrasted. The results prove that the breaker failure is more likely caused by the over-current.