基于直流输电无功控制的多直流馈出电网交流系统过电压最优抑制策略  

An Optimum Strategy for Suppressing AC Overvoltage in Systems With Multiple HVDC Links Based on HVDC Reactive Power Control

作　　者：滕予非 汤涌 张鹏 庞广恒 严磊 

机构地区：[1]国网四川省电力公司电力科学研究院,四川省成都市610072 [2]电网安全与节能国家重点实验室(中国电力科学研究院有限公司),北京市海淀区100192

出　　处：《电网技术》2017年第12期3846-3853,共8页Power System Technology

基　　金：四川省科技厅重点研发计划(2017GZ0054);中国博士后科学基金资助项目(2015M582543)~~

摘　　要：为解决多直流集中外送电网在单回直流故障期间交流电网出现的过电压问题,提出了一种基于高压直流输电无功控制的过电压最优抑制策略。对直流输电系统外送功率受阻时交流系统过电压的机理进行了研究。研究表明,在直流输电系统换相失败或线路故障重启期间,换流器消耗无功明显减少,在交流侧滤波器切除之前,交流系统无功严重过剩,导致换流站交流母线出现较为明显的电压抬升,甚至出现过电压。基于该机理提出了过电压抑制策略,该策略在单回直流故障期间,短时提升近区健全直流逆变侧关断角γ及直流电流指令,在保持健全直流外送功率不变的基础上,增加整流侧换流器的无功消耗,从而抑制过电压的策略。基于最优控制器的设计方法,给出了过电压抑制环节的设计过程及实施方法。中国西南某双直流馈出电网实际仿真算例验证了该抑制环节的有效性。An optimum overvoltage suppression strategy based on HVDC reaction power control is proposed to solve AC overvoltage problem in systems with multiple HVDC links during single HVDC link fault period.Occurrence mechanism of AC overvoltage upon DC power blocking is studied.The research demonstrates that,during period of commutation failure or reboot of HVDC system after a transmission line fault,converters will consume significantly less reactive power,and if AC filters are not disconnected timely,the AC system will subject to surplus reactive power,resulting in voltage rise on AC bus in the converter station,and possibly causing overvoltage.In order to suppress the overvoltage,during the fault period of one HVDC link,the proposed strategy will increase turn-off angel γat inverter side of healthy HVDC links for a short time,and at the same time maintain the active power delivered by the healthy HVDC links.The strategy is designed following the design process of an optimum controller,and implementation method of the strategy is described in detail.Effectiveness of the proposed strategy is verified with simulation case study of a system with double HVDC links in Southwest China.

关 键 词：直流输电系统 无功控制 关断角 过电压 最优控制 

分 类 号：TM721[电气工程—电力系统及自动化]