直流控制系统对直流近区交流线路短路电流幅值的影响

Impacts of Direct Current Control System on Alternating Current Circuit Short-Circuit Current Amplitude near Direct Current Region

在故障期间良好的直流控制系统可以减少故障对电网的伤害。介绍了目前主流的直流控制系统逆变侧的结构及其主要参数,分析了控制系统的低压限流、最大触发角控制、电流放大器和换相失败预测等环节的基本结构,通过PSCAD/EMTDC软件搭建仿真模型,在故障期间分别限制不同控制环节的信号输出,研究其对短路电流幅值的影响,指出换相失败预测环节是影响直流近区交流线路短路电流幅值的直接因素,最大触发角控制和电流放大器环节间接影响短路电流幅值。

During malfunction a good direct current control system could reduce harm to grid from faults. Introduction was made to the structureof the main stream direct current control system at the side of inverter side and its major parameter at present. Analysis was made to the basic structureof low-voltage current-limiting, maximum firing angle control, current amplifier and commutation defeating prediction etc links. The softwarePSCAD/EMTDC was used to construct the simulation model. During malfunction the signal outputs of different control links were limited. Thispaper studied its impact on the short-circuit current amplitude, and pointed out that the commutation defeating prediction link is the direct factorinfluencing on the alternating current circuit short-circuit current amplitude near direct current region and the maximum firing angle control and currentamplifier links indirectly affect on the short-circuit current amplitude.