一种基于修正电压的新型暂态量保护原理  

Novel Transient Protection Principle Based on Corrected Voltage

作　　者：薛士敏 李翔宇 陈文杰 张君婷 张皓明 阴文湘 XUE Shimin;LI Xiangyu;CHEN Wenjie;ZHANG Junting;ZHANG Haoming;YIN Wenxiang(School of Electrical and Information Engineering,Tianjin University,Tianjin 300072,China)

机构地区：[1]天津大学电气自动化与信息工程学院,天津市300072

出　　处：《电力建设》2024年第4期89-99,共11页Electric Power Construction

基　　金：国家电网有限公司总部管理科技项目(5500-202199270A-0-0-00)。

摘　　要：鉴于柔性直流输电系统在线路侧发生故障时具有故障电流上升速度快、幅值大的特点,为保障系统的安全稳定运行,线路保护需在数毫秒内完成故障判别。如何快速可靠识别故障线路是柔性直流系统线路保护的难点之一。针对该难点,提出一种基于修正电压的新型暂态量保护原理。首先,提出一种电压修正算法,其同时利用了短路后电压的幅值和变化率特征,可以更灵敏地识别故障。在此基础上,基于修正电压的积分量实现了对区内故障与正向区外故障的有效区分。其次,提出一种新的方向元件,基于该方向元件构造纵联后备保护判据,解决了单端量保护在高阻故障下灵敏度较低及反向故障误动的问题。最后,基于PSCAD/EMTDC仿真平台搭建四端柔直系统模型,通过仿真验证了本方案的有效性。Considering the characteristics of a flexible DC transmission system,in which the fault current increases rapidly and features a large amplitude when a line fault occurs,a complete fault identification of the line must be accomplished within a few milliseconds to ensure the safe and stable operation of the system.Rapidly and reliable identifying faulty lines remains challenging in protecting the lines of flexible DC transmission systems.Hence,this study proposes a new transient protection principle based on corrected voltage.First,a voltage-correction algorithm is proposed that simultaneously utilizes the amplitude and rate of change of voltage after a short circuit to identify faults more sensitively.Subsequently,an integral based on a corrected voltage is used to effectively distinguish between internal and forward external faults.Second,a new directional element is proposed to construct a pilot backup-protection criterion,which solves the problems of low sensitivity under high-resistance faults and the reverse fault misoperation of single-terminal protection.Finally,a fourterminal flexible DC system model is constructed based on the PSCAD/EMTDC simulation platform to verify the effectiveness of the scheme via simulation.This work is supported by the Science and Technology Project of SGCC(No.5500-202199270A-0-0-00).

关 键 词：柔性直流输电系统 故障识别 暂态量保护 线路保护 

分 类 号：TM773[电气工程—电力系统及自动化]