一种VSC-MTDC系统的综合协调控制策略

针对直流网络中功率不同程度的缺额提出了一种综合协调控制策略,在设计下垂控制运行特性曲线时综合考虑直流线路电阻上的压降和换流站的功率裕度,并在送端定有功功率换流站中增加下垂控制,避免换流站退出运行或者功率缺额过大导致直流电压失稳的情况。在PSCAD/EMTDC仿真软件中搭建了5端柔性直流输电系统模型,并进行仿真验证。所提出的综合协调控制策略在直流网络出现不平衡功率时,不仅能使直流网络中的潮流最优化,而且直流电压具有很强的刚性,同时也增加了多端柔性直流输电(voltage source converter multi-terminal direct current,VSCM TDC)系统的运行稳定性。

Comprehensive Coordination Control Strategy for VSC-MTDC System

This paper proposes a comprehensive coordinated control strategy,which is aimed at the different degrees of unbalance power in DC network.The margin droop control strategy,which is considering both the voltage droop on DC line resistance and the power margin of converter station in the design of operating characteristic curve of droop control,is introduced in the active-power controller,to ensure the stability of DC voltage when the unbalanced power is too large or the converter station out of operation.Transient simulation and analysis by establishing a simulation model of the five-terminal flexible DC transmission system in PSCAD/EMTDC show that not only the proposed control strategy can optimize the power flow when there is a large unbalance power in the DC network,but also the DC voltage has a strong rigidity,and the stability of the VSC-MTDC (voltage source converter multi-terminal direct current) system also has been improved.