基于PSCAD/EMTDC的背靠背高压直流输电系统仿真

Simulation of back-to-back HVDC system with PSCAD / EMTDC

为了研究灵宝背靠背换流站在交流系统发生故障时的换相失败过程,利用电磁暂态仿真软件PSCAD/EMTDC对灵宝背靠背高压直流输电系统进行了建模,并在此基础上对高压直流输电系统中常见的故障进行了仿真分析,其中包括逆变侧交流系统发生三相故障和单相故障的情况。仿真结果表明,在PSCAD/EMTDC环境下建立的模型能够比较准确地描述在暂态过程中背靠背直流输电系统的动态特性,可以为现场运行以及故障分析提供参考。在系统中加入故障检测控制环节,根据电压和电流的变化,适时增大提前触发角,可以有效地预防换相失败。

PSCAD/EMTDC（Power System Computer Aided Design/Electro-Magnetic Transient in DC system） software is used to establish the model of Lingbao back- to- back HVDC（High Voltage DC transmission） system in studying its commutation failure during AC system fault. Based on it,the general faults of HVDC system are simulated,including three-phase fault and single- phase fault of AC system at inverter side. Simulation results show that, the model built in PSCAD/EMTDC can accurately simulate the dynamic behavior of back- to- back HVDC system in transient process and provide references for field operation and fault analysis. By adding the fault detection ＆control unit in system,the advanced firing angle is raised to effectively prevent the commutation failure according to the change of voltage and current.