真空断路器开断35kV并联电抗器的三相建模仿真与过电压抑制研究

Three-phase Modeling of the Vacuum Circuit Breaker Switching off 35 kV Shunt Reactors and Overvoltage Suppression

为探究真空断路器开断35 kV并联电抗器时过电压产生机理和改进现有仿真模型的不足,笔者简单综述了真空断路器开断感性小电流的仿真研究现状,基于ATP-EMTP电磁暂态仿真软件,利用Fortran语言在MODELS模块中编写控制程序,建立40.5 kV真空断路器开断时电弧重燃三相模型,搭建了真空断路器开断35 kV并联电抗器三相仿真电路并考虑了断路器、三芯电缆三相间的寄生参数。在研究回路无任何保护情况下,断路器负载侧相间电压达到235 kV(7.1 p.u.),对地电压达到145 kV(4.4 p.u.)。仿真结果表明:三相多次重燃和"虚拟截流"现象是此类事故的主要原因。最后提出几点抑制开断并联电抗器时产生过电压的措施。

To explore the generation mechanism of overvoltage when a vacuum circuit breaker （VCB） switches off 35 kV shunt reactors and to improve the existing simulation model, a general review of simu- lation researches on vacuum circuit breakers switching off small reactive current is firstly given. Fortran language is used to write the control program in MODELS module, an arc reignition three-phase simulation model of a 40.5 kV VCB switching off shunt reactors is established in ATP-EMTP to simulate the field tests. The VCB and the cable＇s three-phase parasitic parameters are considered in the simulation. In the case of no protection for the researched loop, the load-side voltage of the VCB is 235 kV （7.1 p.u.）, and the ground voltage reaches 145 kV （4.4 p.u.）. Simulation results show that the multi-reignitiion of three phases and the virtual closure phenomenon mainly cause such overvoltage accidents. Finally, some suppression measures against the overvoltage induced by switching off the shunt reactors are presented.