大规模风电接入的柔性直流电网故障电流协同抑制方法  

Coordinated Suppression Method for Fault Current of Flexible DC Power Grid Integrated with Large-scale Wind Power

作　　者：江守其 李国庆[1] 辛业春 王丽馨 杨勇[1] JIANG Shouqi;LI Guoqing;XIN Yechun;WANG Lixin;YANG Yong(Key Laboratory of Modern Power System Simulation and Control&Renewable Energy Technology,Ministry of Education(Northeast Electric Power University),Jilin 132012,China)

机构地区：[1]现代电力系统仿真控制与绿色电能新技术教育部重点实验室(东北电力大学),吉林省吉林市132012

出　　处：《电力系统自动化》2020年第23期125-134,共10页Automation of Electric Power Systems

基　　金：国家电网公司科技项目(5102-201999343A-0-0-00)。

摘　　要：基于模块化多电平换流器(MMC)柔性直流电网是实现大规模可再生能源发电汇集、多能互补和友好型并网的有效手段。针对直流断路器大电流开断成本高和技术难度大的问题,提出了一种适用于大规模风电接入的柔性直流电网故障电流协同抑制方法。通过分析直流故障特性,揭示了故障电流的关键影响因素,在此基础上,提出了MMC主动限流控制方法,并针对网侧和风电场侧换流站分别设计了参数选取原则,其中网侧换流站的限流性能可自适应于直流母线电压,在抑制故障电流的同时兼顾直流电网的快速恢复。针对风电场侧换流站,提出了集成限流功能的耗散电阻配置方法,使其同时具备解决直流电网功率盈余问题和降低桥臂换流阀电流应力的能力,并提出了其与主动限流控制以及直流断路器的协调配合方法,在保证风电场安全运行的同时协同抑制故障电流,从而降低对直流断路器开断速度、容量及其制造成本的需求。最后,基于RTLAB OP5600实时数字仿真平台搭建了四端柔性直流电网仿真模型,验证了所提方法的有效性和可行性。Modular multilevel converter(MMC)based DC power grid is an effective means to achieve large-scale renewable energy integration,multi-energy complementarity and friendly grid-connection.In order to solve the problems such as high cost and technical difficulty of DC circuit breaker(DCCB),a coordinated method for fault current suppression of the DC power grid connected with large-scale wind power is proposed.Based on the analysis of DC fault characteristics,the key influencing factors of fault current are revealed,and an active current-limiting control(ACLC)method for MMC is proposed.Then the parameter selection principles are designed for the grid-side MMC(GSMMC)and the wind-farm-side MMC(WFMMC).The current-limiting performance of GSMMC can be adaptive to the DC bus voltage,which can limit the fault current while ensuring the rapid recovery of the DC grid.A configuration method of dissipative resistors with integrated current-limiting function is proposed for WFMMC,which can solve the problem of surplus power in the DC power grid and reduce the current stress of converter valves.Based on this,a coordinated method of dissipative resistors,ACLC,and DCCB is proposed to coordinately limit fault current while ensuring the safe operation of the wind farm,thereby reducing the requirement of breaking speed,capacity and manufacturing cost of DCCB.Finally,a four-terminal DC power grid simulation model is built based on the RTLAB OP5600 real-time digital simulation platform,which verifies the effectiveness and feasibility of the proposed method.

关 键 词：直流电网 主动限流控制 参数选取原则 耗散电阻 协同抑制方法 

分 类 号：TM614[电气工程—电力系统及自动化] TM721.1