直流配电系统极间短路故障特性分析

Pole-to-pole Short-circuit Fault Characteristic Analysis for DC Distribution System

直流配电系统故障后换流阀不闭锁运行有助于提高直流供电的可靠性,限流技术的发展及未来绝缘栅双极型晶体管等电力电子器件过电流能力的增强使得换流阀不闭锁情况下的故障机理研究具有意义。本文针对基于两电平电压源型换流器的双端直流配电系统,假设换流阀中的绝缘栅双极型晶体管具有足够的过电流能力,分析了极间短路故障后换流阀不闭锁条件下的故障机理,对比了定电压控制和定功率控制方式下极间短路的故障特征,并在PSCAD/EMTDC平台中进行了仿真分析,为直流配电系统保护提供了理论依据。

In a DC distribution system,the operation with unblocked converter valve after line fault can improve the re⁃liability of DC power supply.Moreover,along with the development of the current-limiting technology and the growing capability of power electronic devices(e.g.,IGBT)to withstand the over-current,it is significant to study the fault mechanism with unblocked converter valve.In this paper,under the promise that the IGBT in the converter valve has enough over-current resistance capability,the pole-to-pole short-circuit fault mechanism of a two-level voltage source converter(VSC)based two-terminal DC distribution system is analyzed under the condition of unblocked converter valve,and the pole-to-pole short-circuit fault characteristics under voltage-rated and power-rated control are compared.Simulation analysis is carried out on the PSCAD/EMTDC platform,providing a theoretical basis for the protection of the DC distribution system.