摘要
针对传统换流器控制策略下柔性直流(voltage source converter based HVDC,VSC-HVDC)输电系统难以有效参与交流系统频率的动态调节以及交直流系统间功率传输不平衡等问题,在对虚拟同步发电机(virtual synchronous generator,VSG)运行机制特性进行研究的基础上,提出了一种基于VSG技术的VSC-HVDC输电系统受端换流器控制策略。首先,基于VSC-HVDC输电系统拓扑模型,分析了换流站虚拟同步化的可行性;其次,将具有有功模糊PI下垂控制的VSG技术引入到高压直流输电系统,通过调整下垂系数,使柔性直流输电系统逆变器在稳态运行及暂态故障下可以保障系统有功功率平衡传输,使其具有协调控制交流系统频率和直流系统电压的能力;最后,在Matlab/Simulink中构建了一个三端系统用于仿真验证。结果表明:VSC-HVDC输电系统在采用VSG控制策略后,可以改善交流电网的惯性水平,使频率变化得到衰减,其调压控制功能也能在稳态和暂态下提供较好的功率支撑作用,有效提高了交直流系统的稳定性和可靠性。
With the traditional converter control strategies,the dynamic frequency regulation of the AC power system and the unbalanced power transmission between the AC and DC systems are hard to be involved in voltage source converter based high voltage direct current( VSC-HVDC) system. Aiming at the problem,on the basis of the research on the characteristics of the virtual synchronous generator( VSG) technology,a VSC-HVDC inverter control strategy based on VSG technology is proposed. Firstly,according to the VSC-HVDC system topology model,the feasibility of virtual synchronization of converter station is analyzed. Secondly,the VSG technology with fuzzy PI droop control for active power is introduced into the HVDC transmission system. By adjusting the droop coefficient,the inverter of the flexible HVDC transmission system can ensure the active power transmission balance when the system under steady-state operation and transient faults,so that it has the ability to coordinate control the AC system frequency and the DC system voltage. Finally,a model of three-terminal system is built in Matlab/Simulink for simulation verification. The results showthat the VSC-HVDC system can improve the inertial of the AC grid and reduce the change rate of frequency after adopting the VSG control strategy. The FMcontrol can provide better support in the steady state and transient state,which improved the performance of AC and DC system effectively,as well as the reliability of the system.
作者
刘中原
王维庆
王海云
袁成玉
王亮
李永钦
丁文彬
LIU Zhongyuan;WANG Weiqing;WANG Haiyun;YUAN Chengyu;WANG Liang;LI Yongqin;DING Wenbin(Engineering Research Center of Ministry of Education for Renewable Energy Power Generation&Grid Technology,School of Electrical Engineering,Xinjiang University,Urumqi 830047,China;State Grid Urumqi Western Suburb Power Supply Company,Urumqi 830047,China)
出处
《电力建设》
北大核心
2019年第2期100-108,共9页
Electric Power Construction
基金
国家自然科学基金项目(51667020)
新疆维吾尔自治区重点实验室项目(2016D3021)~~
关键词
柔性直流输电
虚拟同步机
受端换流器
调频特性
直流电压协调控制
voltage source converter based high voltage direct current
virtual synchronous generator
inverter
frequency modulation
DC voltage coordinated control
