电压源换流器接地方式对直流配电系统的影响

Influence of voltage source converter grounding mode on DC distribution system

针对低压直流(Low Voltage Direct Current,LVDC)配电系统分析比较了电压源换流器不同接地方式的优缺点。分别在换流器电容中点直接接地和高阻接地方式下,对换流器交流出口处不对称故障特性和直流线路单极接地故障特性进行了分析,并建立LVDC电磁暂态模型进行了仿真研究。对比系统不同工况下的暂态性能可知,电压源换流器电容中点高阻接地方式优于直接接地方式。高阻接地的方式对限制故障电流更为有利,同时也有利于直流配电系统故障消除后的快速恢复,这为未来直流配电系统保护方案的配置奠定了基础。

For the low voltage direct current（LVDC） distribution system, the advantages and disadvantages of the different grounding modes of the voltage source converter are analyzed and compared. In the converter capacitor directly grounding and high resistance grounding mode, the converter AC outlet of asymmetric fault characteristics and DC line pole grounding fault characteristics are analyzed, and the LVDC electromagnetic transient model is established and studied by simulation. Comparison of the system transient performance under different operating conditions shows that voltage source converter capacitor high resistance grounding mode is better than the direct grounding way. High resistance grounding to limit fault current is more favorable, and it is also beneficial to the rapid recovery after the DC power distribution system is eliminated, which lays the foundation for the protection scheme of DC power distribution system in the future.