一种应用于多端柔性直流系统的新型潮流控制器

A Novel DC Power Flow Controller for Multi-terminal Flexible DC System

针对多端柔性直流系统中潮流难以灵活控制的缺点,提出了一种新型潮流控制器,该控制器能够在不与交流侧进行能量交互的前提下实现直流潮流控制。首先,以三端柔性直流系统为例,对多端柔性直流系统的潮流进行分析,提出了该直流潮流控制器的拓扑结构及与系统连接方式;其次,通过对直流潮流控制器工作原理的分析,得出了针对潮流控制器2种不同工作模式下的控制策略;最后,在PSCAD/EMTDC仿真平台上搭建了一个装有直流潮流控制器的三端柔性直流系统模型,通过对3种运行工况的仿真实验,验证了该潮流控制器在具有较好的潮流控制能力的同时,又能实现自身的功率平衡。

To achieve flexible control of DC power flow in multi-terminal flexible DC system, this paper proposes a new type power flow controller. It can realize flexible control of power flow, and not exchange active power with AC system. Firstly, DC power flow is analyzed in a three-terminal DC system. Secondly, topology of the controller and its system connection manners are presented. Working principle and operating characteristics of the controller are analyzed and control strategies of two different operating states are pointed out. Finally, a three-terminal DC grid based on flexible voltage source converter is modeled and three operation modes are tested in PSCAD/EMTDC to demonstrate such system＇s operation. It is concluded that such controller can control power flow flexibly and achieve power balance by itself.