逆变侧控制策略对换相失败影响的研究

Research on Influence of Inverter Side Control Strategy on Commutation Failure

高压直流输电实际工程中稳态运行时逆变侧控制策略主要有2种:定关断角控制策略和定电压控制策略,目前针对2种控制策略对换相失败影响的对比研究较少。基于实际工程参数,分别建立了定关断角和定电压控制策略的高压直流输电PSCAD/EMTDC模型,模型控制系统均按照实际工程控制系统搭建。分析了2种控制策略的控制方式,对比研究了2种控制策略对换相失败的抵御能力以及换相失败后的恢复特性。研究表明,总体来说2种控制策略对换相失败的抵御能力无明显差异,单相故障下定关断角控制策略略优于定电压控制策略;相同故障条件下,定关断角控制策略换相失败持续时间小于定电压控制策略,而定电压控制策略在换相失败恢复时间方面优于定关断角控制策略。研究为以后直流工程控制策略的选择和优化具有一定指导意义。

There are two main inverter side control strategies in actual HVDC engineering under steady-state operation, i.e. constant extinction angle control and constant voltage control. At present, few comparative studies were conducted on the two control strategies. Based on actual engineering parameters, two HVDC PSCAD/EMTDC models were established using constant extinction angle and constant voltage control strategies, respectively. Control systems of the models were set up in accordance with control system of actual engineering. Control modes of the two strategies were analyzed and a comparison of commutation failure prevention ability and recovery characteristics after commutation failure between the two strategies was performed. Research shows that commutation failure prevention ability of the two strategies has no obvious difference in general, while constant extinction angle control is slightly better than constant voltage control under single-phase fault. Commutation failure duration of constant extinction angle control is shorter than that of constant voltage control, while constant voltage control is better than constant extinction angle control in term of commutation failure recovery time under the same fault conditions. The study has certain guiding significance for selection and optimization of control strategy of HVDC project in future.