特高压混合多端直流输电系统中串联换流阀组间的电压平衡控制策略  

Voltage Balancing Control Strategy of Series-connected Converter Valve Groups in Hybrid Multi-terminal UHVDC Transmission System

作　　者：郑安然[1] 郭春义[1] 崔鹏[1] 赵成勇[1] ZHENG Anran;GUO Chunyi;CUI Peng;ZHAO Chengyong(State Key Laboratory for Alternate Electrical Power System With Renewable Energy Sources(North China Electric Power University),Changping District,Beijing 102206,China)

机构地区：[1]新能源电力系统国家重点实验室(华北电力大学)

出　　处：《电网技术》2019年第9期3408-3414,共7页Power System Technology

基　　金：国家自然科学基金资助项目(51877077)~~

摘　　要：特高压混合多端直流输电系统结合了电网换相换流器(line commutated converter,LCC)与模块化多电平换流器(modular multilevel converter,MMC)的优势,可以实现多电源供电、多落点受电的远距离大容量输送要求。针对特高压混合多端直流输电系统中同一换流站内串联换流阀组之间的电压不平衡问题,分析了电压不平衡的原因,并提出了一种基于串联换流阀组间电压–功率偏差量的电压平衡控制策略,该控制策略简单有效便于工程实现。然后基于PSCAD/EMTDC搭建了特高压多端混合直流系统的仿真模型,通过对比切除/投入电压平衡控制时系统的动态特性验证了电压平衡控制策略的有效性。为进一步分析该控制策略对系统动态性能的影响,研究了特高压混合多端系统在功率阶跃变化和交流故障情况的动态响应,结果表明所提出的控制策略简单有效,且在不同运行工况下均可以实现串联换流阀组之间的电压平衡。Hybrid multi-terminal UHVDC transmission system combines the advantages of line commutated converter and modular multilevel converter.It can meet long-distance and large-capacity transportation requirements of multi-source supply and multi-receiving end.Aiming at the voltage imbalance between series converter valve groups in the same converter station of hybrid multi-terminal UHVDC transmission system,this paper analyses the causes of voltage imbalance and proposes a voltage balancing control strategy based on voltage-power deviation between series converter valve groups.The control strategy is simple and effective,and easy to implement in engineering practice.Based on PSCAD/EMTDC,a simulation model of hybrid multi-terminal UHVDC transmission system is built.By comparing the dynamic characteristics of the system when blocking/applying voltage balancing control strategy,effectiveness of voltage balancing control strategy is verified.In order to further analyze the influence of the control strategy on the dynamic performance of the system,the dynamic response of the hybrid multi-terminal UHVDC system under power step change and AC fault is studied.Results show that the proposed control strategy is simple and effective,and can achieve voltage balance between the series converter valve groups under different operating conditions.

关 键 词：特高压混合多端直流输电系统 串联换流阀组 电压–功率偏差量 电压平衡控制 

分 类 号：TM721[电气工程—电力系统及自动化]