抑制多馈入直流换相失败的同步调相机优化配置方法

多馈入直流系统中交流侧短路故障发生后,导致交流系统电压持续降低进而引起多条甚至全部直流同时发生换相失败,使电网安全稳定性受到严重破坏。同步调相机具备过载能力,且其无功输出受系统电压影响小,在面对交流故障带来的电压跌落可以提供较强的无功支撑,从而抑制直流换相失败的发生。为了抑制直流换相失败,提出了一种抑制多馈入直流换相失败的同步调相机优化配置方法,对其安装地点及容量这两个方面同时进行了优化配置。首先从直流换相失败持续时间出发,且考虑各直流间相互作用,提出了一种抑制换相失败效果指标;然后根据电气距离确定了安装待选区域,由无功补偿响应指标筛选出同步调相机最佳补偿地点;随后建立了同步调相机配置优化模型,对最佳配置方案进行二阶段的求解,获得最终配置方案;最后在实际大电网仿真结果表明,所得最终解能够考虑经济性的同时有效抑制交流故障引起的多馈入直流换相失败。

Optimal Configuration of Synchronous Condensers for Suppressing Multi-infeed DC Commutation Failure

After the AC side short-circuit fault occurs in a multi-infeed DC system, the voltage of the AC system will continue to decrease, and will thus cause the commutation failure of multiple or even simultaneous failure of all DCs, which will seriously damage the security and stability of the power grid. The synchronous condenser has overload capability, and its reactive output is negligibly affected by the system voltage. The voltage drop caused by the AC fault can provide strong reactive power support,and can thereby suppress the occurrence of DC commutation failure. To suppress the failure of DC commutation, a synchronous condenser optimization configuration method for suppressing multi-feed DC commutation failure was proposed, which was optimized for both installation location and capacity. Firstly, starting from the duration of DC commutation failure, and taking the interaction between DCs into account, we proposed an effective index for suppressing commutation failure. Then, according to the electrical distance, the area to be selected was determined, and the best compensation location of synchronous condenser was selected by the reactive compensation response index.Thirdly, the configuration optimization model of synchronous condenser was established, and the optimal configuration scheme was solved in two stages to obtain the final configuration scheme. Finally, the actual large-grid simulation results show that the final solution can effectively suppress the multi-feed DC commutation failure caused by AC fault while considering economy.