内蒙古电力技术2024，Vol.42Issue(3)：42-51,10.DOI:10.19929/j.cnki.nmgdljs.2024.0039
大规模直驱风电场经柔直送出系统交直流线路故障特征分析
Analysis on Fault Characteristics of Large-Scale Direct-Drive Wind Farm Passing Through AC/DC Line of VSC-MTDC Transmission System
摘要
Abstract
Aiming at the AC/DC hybrid system with permanent magnet wind field with fault ride-through strategy and multiterminal flexible DC transmission,the fault characteristics of the AC grid fault at the receiving end under the fault ridethrough control target and the fault of the DC system transmission line considering the frequency variation characteristics of the transmission line are analyzed,as well as the response of DC system to AC fault at a large time scale.The research results show that the AC/DC hybrid system model based on RTDS has corresponding fault characteristics under different fault conditions and control strategies,while effectively controlling the development of faults.For example,When the AC grid-connected line fails,the negative sequence current will be suppressed,and the converter station only provides limited positive sequence current to the fault point,and preferentially outputs reactive power.The accumulated unbalanced power of the DC line will cause DC overvoltage phenomenon.Considering the fluctuation of DC voltage,the dq axis current of the receiving end converter station will change,resulting in a short-time increase of about 20%in the fault current of the AC line.When a single-pole grounding fault occurs in the DC line,the fault pole voltage drops rapidly to 0 at a maximum rate of 700 kV/ms,while the non-fault pole voltage rises by two times,and the fault current decreases with the increase of the grounding resistance.When a bipolar fault occurs,the fault current can reach dozens of times of the rated current within milliseconds,with a maximum rate of 8.25 kA/ms,which seriously threatens the safety of power electronic devices,and the voltage rapidly drops to 0.At this time,through the rapid action of the hybrid DC circuit breaker,the fault line is removed before the fault current rises to two times the rated current,so that the system meets the N-1 operation principle.The simulation results are consistent with the theoretical analysis conclusions.关键词
风电场/多端柔性直流输电/交直流混联系统/故障穿越策略/故障特征/RTDSKey words
wind power plant/VSC-MTDC/AC/DC hybrid system/fault ride-through strategy/fault characteristics/RTDS分类
信息技术与安全科学引用本文复制引用
钟鸣,杨志勇,张亚光,王超..大规模直驱风电场经柔直送出系统交直流线路故障特征分析[J].内蒙古电力技术,2024,42(3):42-51,10.基金项目
内蒙古自治区企业重点实验室开放课题"交直流混联系统协调控制下故障特征分析" （）
