多端口直流潮流控制器抑制次同步振荡阻尼控制策略研究

Active Damping Control of Multi-port DC Power Follow Controller for Suppressing Sub-synchronous Oscillation

近年来,仿照传统交流潮流控制器的思想,提出了直流潮流控制器的概念,并针对其拓扑实现方案、稳态运行控制策略以及参与潮流调节时的系统运行特性展开了系统的研究。针对多端口直流潮流控制器(multi-port DC power flow controller,M-DCPFC)运行控制问题,提出了一种M-DCPFC新型控制控制方法,进一步扩展了M-DCPFC的功能性。在保证系统潮流调度需求的基础上,其能够在输电线路上引入补偿虚拟阻尼以抑制换流站次同步振荡电流在直流网络内的传播与扩散,有效地限制了故障影响范围和提高了整体输电系统的可靠性。文中详细分析了次同步振荡下M-DCPFC的阻尼控制机理,并设计了有效的控制策略。最后,在基于RT-lab的实时模型在环仿真测试系统中搭建了5端柔性直流输电系统模型,对所提控制策略进行了不同算例下的验证分析,结果表明了其有效性。

In recent years, inspired by the idea of power flow control devices developed in traditional AC transmission system, the concept of DC power flow controller was proposed and various studies on its topology implementation scheme, steady-state operation control strategy, and system operation characteristics when participating in power flow regulation have been carried out. For the control and operation of the multi-port DC power flow controller(M-DCPFC), a new M-DCPFC control method is proposed in this paper, which further expands the functionality of the M-DCPFC. On the basis of ensuring system power flow regulation requirements, this method is able to introduce virtual damping on the transmission line to suppress the sub-synchronous oscillating current in the DC network, which effectively limits the fault impact region and improves the stability of the overall transmission system. The damping control mechanism of M-DCPFC under sub-synchronous oscillation is analyzed in detail, and the implementation of the control strategy is discussed. A five-terminal flexible HVDC transmission system is developed as the test platform in the real-time model-in-the-loop simulation. The proposed damping control is validated under different cases and shows its effectiveness.