考虑交直流无功交互特性的换相失败预测控制优化方法

Optimization Method for Commutation Failure Prevention Control Considering AC/DC Reactive Power Interaction Characteristics

换相失败预测控制在减小换相失败风险的同时将增大直流系统的无功消耗,但当前研究均未考虑其在多回直流系统与受端电网之间无功交互的影响,因此提出了考虑交直流无功交互特性的换相失败预测控制优化方法。首先,分析了换相失败预测控制作用下交直流混联电网的态势演化规律。然后,综合考虑功率冲击和无功功率来评估各回直流系统对受端电网的影响程度,并据此对换相失败预测控制参数进行优化设置。最后,基于实际电网对所提协调优化方法进行了仿真分析。仿真结果表明,该方法能在有效降低整体换相失败功率冲击的同时,避免直流系统吸收过多无功功率而威胁交直流混联电网的无功电压稳定,有利于故障后的无功电压态势向恢复稳定的方向演化。

Commutation failure prevention(CFPREV)control raises the reactive power consumption of DC system while reducing the risk of commutation failure.However,the interaction effects of reactive power between receiving grid and multiple circuits of DC system are not considered in current research.An optimization method for CFPREV control which considers interaction characteristics of AC/DC reactive power is put forward.Firstly,the law of situation evolution for AC/DC hybrid grid with the CFPREV control is analyzed.Secondly,power oscillation and reactive power are synthetically considered to evaluate the impact of each circuit for the DC system on the receiving-end grid,and parameter improvement of CFPREV control is set accordingly.Finally,based on the actual power grid,the proposed coordinated optimization method is simulated and analyzed.The simulation results show that the proposed method can effectively reduce the overall power oscillation of commutation failure while preventing DC system absorbing excessive reactive power,which causes adverse effects on the reactive voltage stability of AC/DC hybrid grid,and it is beneficial to the evolution of reactive voltage to the direction of restoring stability after fault.