UHVDC系统换相失败故障过程分析及运行参数影响研究

受端交流系统故障是诱发特高压直流系统换相失败的主要原因,严重影响电网安全.为充分明晰交流系统故障下特高压直流系统换相失败期间阀组换相过程和控制响应,通过故障过程的电磁暂态仿真,基于换相面积理论对比阀组实际关断面积和最小关断面积,分析换相失败的主要原因.对运行参数与换相失败和故障恢复的灵敏度展开研究,发现低压限流环节参数...

Analysis of the commutation failure process and a study on the influence of operation parameters on a UHVDC system

An AC system fault at the receiving end is the main cause of commutation failure in an Ultra High Voltage Direct Current (UHVDC) system. This can seriously affect the security of the power grid. To fully clarify the commutation process and control response of a valve group during commutation failure of a UHVDC system under an AC system fault, the actual extinction area and the minimum extinction area of the valve group are compared, and the main reason for commutation failure is analyzed through the electromagnetic transient simulation of the fault process. Sensitivity of operational parameters and commutation failure and the fault recovery process is studied. It is found that the parameters of a Voltage Dependent Current Order Limiter (VDCOL), proportional coefficient and integral coefficient of inverter control have obvious effects on commutation failure and the fault recovery process. These aspects can be the first choice for optimizing of the control system. This paper can provide a reference for commutation failure analysis and stable operation of a UHVDC converter station.This work is supported by the National Key Research and Development Program of China (No. 2016YFB0900600).