多端柔性直流电网平抑风电波动的协调控制策略

为了充分利用西南区域和华中区域调节速度快、调峰能力强的水电资源来跨区平抑"三北"地区由于风电波动所造成的频率大幅波动,提出一种在电压源型换流器型多端直流输电(VSC-MTDC)网络中跨区域平抑风电波动的附加控制方法,并将该风电跨区调节附加控制和有功功率-频率下垂控制(P-f控制)相结合,制定了具体的协调控制策略。当风电装机容量较大的区域电网中由于风电功率波动而导致频率偏移过多时,附加控制启动,抑制该区域电网频率的继续偏移。在风电剧烈波动或者出现其他故障的极端情况下,P-f控制启动,配合附加控制实现网络中各区域电网的频率稳定。RTDS仿真结果表明,所提策略能够有效地使风电波动被其他水电资源丰富的地区所调节,且维持各互联电网稳定运行。

Coordinated control restraining wind power fluctuation of VSC-MTDC

An additional control for restraining the wind power fluctuation of Three Northern Areas by applying the fast and sufficient peak-load regulation capacity of Southwestern and Central Areas is proposed to suppress the frequency oscillation of interregional VSC-MTDC(Voltage Source Converter-based Multi-Terminal HVDC) system, which is combined with the P-f control(active power & frequency droop control) to form a coordinated control strategy. The additional control is activated when the wind power fluctuation causes the frequency deviation of regional grid with larger wind power capacity bigger than the limit. In the extreme conditions of violent wind power fluctuation or system fault, the P-f control starts to coordinate with the additional control for maintaining the system frequency. The results of RTDS simulation verify that, the proposed control strategy uses the rich hydropower of other areas to effectively suppress the frequency oscillation and maintain the stability of interconnected power grids.