站间通信延时对换相失败与恢复特性的影响

Effect of inter station communication delay on commutation failure and recovery characteristics

针对现有特高压直流输电控制策略的研究中未考虑站间通信延时的问题,文中基于CIGRE HVDC模型,分析站间通信延时对换相失败及恢复特性的影响。首先分析换相失败的影响因素,得出逆变侧交流系统电压降低与直流电流上升是引起换相失败的主要因素;其次分析站间通信延时对换相失败的影响,得出站间通信延时会增大换相失败风险;然后分析不同通信延时下的整流侧与逆变侧电流指令值关系,得到三种典型工况,并详细分析三种不同工况下通信延时对换相失败恢复特性的影响;最后基于PSCAD/EMTDC仿真软件搭建CIGRE HVDC标准测试系统,仿真分析不同故障电阻下不同通信延时对换相失败及恢复特性的影响。

As the existing U⁃HVDC(ultra⁃high voltage direct current)control strategy does not consider the inter station communication delay,the influence of inter communication delay on commutation failure and recovery characteristics are analyzed based on CIGRE HVDC model.The influencing factors of commutation failure are analyzed.It is concluded that the main factors causing commutation failure are the decrease of AC system voltage and the rise of DC current at the inverter side.After analysing the influence of inter station communication delay on commutation failure,it is concluded that inter station communication delay will increase the risk of commutation failure.Three typical operating conditions are obtained by analysing the relationship between the current command values on the rectifier side and the inverter side under different communication delays,and the impact of communication delays on commutation failure and recovery characteristics under three different operating conditions is analyzed in detail.A CIGRE HVDC standard testing system is built based on PSCAD/EMTDC simulation software to simulate and analyze the impact of different communication delays on commutation failure and recovery characteristics under different fault resistors.