基于智能多代理系统的VSC-MTDC系统分布式控制策略

应用智能多代理系统(MAS),提出一种基于电压源型换流器的多端柔性直流输电(VSC-MTDC)系统的控制策略。首先,基于网络图论的概念,提出了MAS最优通信拓扑设计方法。然后,基于VSC-MTDC系统传统下垂控制给出了完整的MAS控制策略,设计了以换流站交流母线电压、频率为输入信号的频率支撑Agent(FSA)模块和以换流站负载率为输入信号的功率分配Agent(PAA)模块,并深入讨论了FSA和PAA的配合控制问题。其中,FSA通过控制换流站的功率输出对交流电网提供快速频率支撑,PAA通过换流站之间的输出功率再分配保证VSC-MTDC系统中各换流站负载率的均衡分配。最后,基于DIgSILENT/PowerFactory电力系统仿真软件搭建了六端VSC-MTDC系统,通过非线性仿真证明了所提通信网络拓扑优化方法的有效性,并且验证了所提控制策略能迅速实现系统频率的稳定、有效防止换流站功率的过载。

Distributed control strategy of VSC-MTDC system based on multi-agent system

A control strategy of VSC-MTDC(Voltage Source Converter based Multi-Terminal Direct Current) system is proposed by using MAS(Multi-Agent System). Firstly, a design method of MAS optimal communication topology is proposed based on the concept of network graph. Then, the complete MAS control strategy based on the traditional droop control of VSC-MTDC system is given, the FSA(Frequency Support Agent) module with the AC bus voltage and frequency of converter station as input signals and the PAA(Power Allocation Agent) module with the load rate of converter station as input signal are designed, and the coordination control between FSA and PAA is discussed. FSA provides fast frequency support for the AC power grid by controlling the power output of the converter station and PAA equalizes the load rate among converter stations in VSC-MTDC system through the output power reallocation. Finally, a six-terminal VSC-MTDC system is established based on the power system simulation software DIgSILENT/PowerFactory, and the nonlinear simulation proves the effectiveness of the proposed network topology optimization method and verifies that the proposed control strategy can realize the frequency stability of the system quickly and prevent the overload of converter station power effectively.