工频零点电流转移限流及40.5kV快速真空开关仿真

随着电网的发展和负荷密度的增加,故障电流不断增大,如不采取措施,一些区域的故障电流将超过现有断路器的开断能力。笔者提出了一种基于工频零点电流转移的限流器方案。由快速真空开关和限流阻抗并联组成限流器,放弃限制故障电流的第一个峰值,降低了限流器实现的难度。笔者从工作电压、电流转移、动稳定性和热稳定性,以及快速真空开关等方面,论证了这种限流器的可行性。建立了基于等效回路法的仿真分析方法,对40.5kV真空断路器的电磁斥力机构进行了计算和优化。结果表明,工频零点电流转移型限流器所需的快速真空开关是可以实现的。

Fault Current Limiter Based on Current Commutation at Power Frequency Zero and Simulation of 40.5 kV Fast Vacuum Switch

With the development of power grid and the increase of load density,fault current gets larger to break the interruption capacity of the existing circuit breakers in some areas if countermeasure is not taken.This paper presented a fault current limiter (FCL) scheme based on current commutation at power frequency zero.The FCL is composed of a fast vacuum switch and a fault current limiting impedance connected in parallel.This scheme ignores limiting the first peak of fault current so as to simplify the implementation of FCL.Investigations on the issues of working voltage,current commutation,dynamic stability,thermal stability and fast vacuum switch were performed to demonstrate the feasibility of the FCL.A simulation method based on the equivalent circuit method was proposed to optimize electromagnetic repulsion mechanism for a 40.5 kV vacuum circuit breaker.The simulation results show that the fast vacuum switch for the FCL is realizable.