级联型混合直流输电系统的自适应下垂控制策略研究  

Adaptive droop control strategy of cascaded hybrid HVDC system

作　　者：曾蕊[1] 李保宏[1] 江琴[1] 刘天琪[1] ZENG Rui;LI Baohong;JIANG Qin;LIU Tianqi(College of Electrical Engineering,Sichuan University,Chengdu 610062,China)

机构地区：[1]四川大学电气工程学院,四川成都610062

出　　处：《电力工程技术》2022年第2期60-66,共7页Electric Power Engineering Technology

基　　金：国家重点研发计划资助项目(2018YFB0904600)。

摘　　要：文中研究了受端级联型混合高压直流(简称混合直流)输电系统的控制特性,分析了受端柔性直流在下垂控制模式下对级联型混合直流控制特性的影响,明确了混合级联直流的总体伏安特性曲线。相比于主从控制,采用下垂控制的模块化多电平换流器(MMC)具有同时控制直流电压和直流功率的能力,不会出现功率反送现象。但在下垂控制作用下,MMC无法实现直流电压的准确控制。因此,文中提出一种受端级联型混合直流输电系统的自适应下垂控制策略,该策略可根据系统直流电流的变化实时调节下垂特性,避免MMC的直流电压随直流电流的变化而产生波动。最后,基于PSCAD/EMTDC的仿真结果验证了所提控制策略的有效性,该策略可以实现混合直流输电系统直流电压的准确控制,提高了混合直流输电系统的稳定性。In this paper,the control characteristic of cascaded hybrid high voltage direct current(HVDC)system is studied.The influence mechanism of modular multilevel converter(MMC)inverters to the whole hybrid HVDC are investigated,and the complete voltage-current characteristic curves of the hybrid HVDC are obtained in droop control modes.Compared with the master-slave control,MMCs in droop control have ability to control both DC voltage and DC power,and the power reverse transmission will not occur.However,MMCs in droop control cannot control DC voltage accurately.Thus,an adaptive droop control strategy of cascaded hybrid HVDC system is proposed.The droop curve can be moved in real time adaptively according to DC current,which avoid the fluctuations of DC voltage due to the change of DC current.Finally,the simulation results verify the effectiveness of the proposed strategy based on PSCAD/EMTDC.This strategy can adjust the droop curves adaptively and realize accurate control of DC voltage in hybrid HVDC system,which improves the stability of the hybrid HVDC system.

关 键 词：受端级联 混合高压直流(HVDC) 下垂控制 伏安特性 自适应控制 电压波动 

分 类 号：TM721[电气工程—电力系统及自动化]