双端柔性低频输电系统低频侧两相运行控制策略  

Two-phase Operation Control Strategy on Low-frequency Side of Two-terminal Flexible Low-frequency Transmission System

作　　者：吴小丹[1,2] 卢宇 董云龙[1,2] 邹强 WU Xiaodan;LU Yu;DONG Yunlong;ZOU Qiang(NR Electric Co.,Ltd.,Nanjing 211102,China;NARI Group Corporation(State Grid Electric Power Research Institute),Nanjing 211106,China)

机构地区：[1]南京南瑞继保电气有限公司,江苏省南京市211102 [2]南瑞集团有限公司(国网电力科学研究院有限公司),江苏省南京市211106

出　　处：《电力系统自动化》2022年第19期132-144,共13页Automation of Electric Power Systems

基　　金：国家重点研发计划资助项目(2021YFB2401100);国家电网有限公司科技项目(5211DS22002C)。

摘　　要：基于模块化多电平矩阵变换器(M3C)的柔性低频输电系统(LFTS)具备低频侧两相运行能力,但其控制策略需特殊设计。文中首先介绍了双端柔性LFTS的基本情况及两相运行的基本要求,给出基于工、低频侧输入解耦及桥臂环流控制的M3C数学模型。为实现低频侧不对称运行条件下桥臂子模块电容电压的均衡,提出M3C桥臂功率再平衡的双重低频环流控制法。然后,分别给出两相运行条件下V/f站和PQ站的低频侧输入电流控制策略,并在静止坐标系统通过对9个桥臂电流的完全独立控制实现两个站M3C的控制。最后,在实时数字仿真系统中搭建双端柔性LFTS仿真模型,分别对稳态、动态及交流系统不对称故障等典型工况进行仿真测试。仿真测试结果表明,所提控制策略可有效实现双端柔性LFTS的低频侧两相运行要求。The flexible low-frequency transmission system(LFTS)based on the modular multilevel matrix converter(M3C)has the capability of two-phase operation on the low-frequency side,but its control strategy needs special design.First,this paper describes the basic condition of two-terminal flexible LFTS and the basic requirements of two-phase operation,and proposes a mathematical model of M3C for fundamental-frequency and low-frequency side input decoupling control and bridge arm circulating current control.In order to balance the capacitor voltage of bridge arm sub-modules under the asymmetric operation condition on the low-frequency side,a dual low-frequency circulating current control method for rebalancing the bridge arm power of M3C is proposed.The input current control strategy on the low-frequency side of V/f and PQ stations under the two-phase operation condition is given,respectively.Then the control of M3Cs for two stations is realized by completely independent current control of nine bridge arms in the static coordinate system.Finally,the simulation model of a two-terminal flexible LFTS is built in the realtime digital simulation(RTDS)system,and simulation tests are carried out for typical operation conditions such as the steady-state operation,the dynamic operation and the AC system asymmetric fault.The simulation test results show that the proposed control strategy can effectively meet the requirements of two-phase operation on the low-frequency side of the two-terminal flexible LFTS.

关 键 词：柔性低频输电 模块化多电平矩阵变换器 双端系统 两相运行 低频环流控制 

分 类 号：TM46[电气工程—电器] TM73