基于瞬时功率相平面的柔性直流电网后备保护  

VSC-HVDC Backup Protection Based on Instantaneous Power Phase Plane

作　　者：王洪彬[1] 周念成[1] 廖建权 范炳昕 宋佳航 倪静怡 WANG Hongbin;ZHOU Niancheng;LIAO Jianquan;FAN Bingxin;SONG Jiahang;NI Jingyi(State Key Laboratory of Power Transmission Equipment&System Security and New Technology,Chongqing University,Chongqing 400044,China;College of Electrical Engineering,Sichuan University,Chengdu 610065,China)

机构地区：[1]输配电装备及系统安全与新技术国家重点实验室(重庆大学),重庆400044 [2]四川大学电气工程学院,成都610065

出　　处：《高电压技术》2023年第3期1273-1283,共11页High Voltage Engineering

基　　金：国家自然科学基金(52077017,52207126)。

摘　　要：基于双端信息的柔性直流电网保护方法具有无需整定阈值、耐受过渡电阻能力强、保护线路全长、可靠性高等优势,可以弥补单端信息保护的缺陷。为实现直流电网线路故障的全范围检测,同时实现后备保护与主保护的协调配合,提出了一种基于故障分量瞬时功率相平面的直流电网线路双端保护方法。首先建立多端柔性直流电网模型,利用回路分析法推导短路故障电流和电压,计算故障分量瞬时功率。然后分析不同故障类型下正负极故障分量瞬时功率的和差特征,分别利用功率差与功率和构造相平面,实现故障区域识别与故障选极。同时通过引入低电压判据,对故障分量瞬时功率重新进行计算,消除线路出口处存在保护死区的问题。该保护方法具有良好的选择性,能够保护线路全长,且具有较好的耐受过渡电阻能力。The VSC-HVDC protection method based on double-terminal information has the advantages of no setting threshold,strong resistance to transition resistance,full length of protection line,and high reliability.It can make up for the defects of single-terminal information protection.In order to realize the full range of fault detection for DC grid lines and realize the coordination between backup protection and main protection,a dual-terminal protection method based on fault component instantaneous power phase plane was proposed.Firstly,a multi-terminal flexible DC grid model was es-tablished,the short-circuit fault current and voltage were deduced by loop analysis method,and the instantaneous power of fault component was calculated.Then,the sum and difference characteristics of the instantaneous power of the positive and negative fault components under different fault types were analyzed,and the phase plane was constructed by the power difference and power sum,respectively,to realize fault area identification and fault pole selection.At the same time,by introducing low voltage criterion,the instantaneous power of fault component was recalculated to eliminate the prob-lem of protection dead zone at the line outlet.The protection method has good selectivity,can protect the whole length of the line,and has good resistance to transition resistance.

关 键 词：柔性直流电网 后备保护 瞬时功率 相平面 故障区域识别 故障选极 

分 类 号：TM773[电气工程—电力系统及自动化] TM721.1