动车组升降弓过电压及抑制措施仿真分析

Overvoltage in CRH Reactor Lifting Process and Simulation Analysis of Restraining Measures

动车组在过分相、降弓等工况下均可产生过电压问题,针对动车组在站内升降弓过程中出现的过电压现象,文中应用MATLAB搭建受电弓升降等效电路,建立电磁式电压互感器的仿真模型;结合仿真和理论分析指出电压互感器在受电弓下降过程中发生低频铁磁振荡;升弓过程是电源电压稳态分量和回路自身高频振荡暂态分量的叠加产生过电压。对比升降弓的仿真结果可知升降弓会给电压互感器带来不同的危害。文中提出在动车组降弓时,切除高压电缆可以有效地降低电压互感器的励磁电流。

China Railway High-speed（CRH）train will produce overvoltage problem during passing neutral section,lifting reactor and so on. Aiming at this phenomenon of overvoltage, this paper builds reactor lift equivalent circuit by using the simulation software MATLAB, establishing simulation model of potential transformer installed on the roof. Combining simulation and theory, it is pointed that low-voltage transformer ferromagnetic oscillations in the reactor drop process will result in overvoltage. In the reactor raise process, overvoltage is superimposed on the steady-state component of the supply voltage and transient component of high frequency oscillation circuit itself. Comparing the results, it indicates that the two simulations will bring different harms to the voltage transformer. This paper presents to remove high voltage cable in reactor lowering;it can effectively reduce the excitation current.