基于测量波阻抗相位特征的三端混合直流线路纵联保护  

Pilot protection of a three-terminal hybrid DC line based on phase characteristics of measured wave impedance

作　　者：公冶令姣 张大海[1] 武传健 王雪芹 倪平浩[1] GONGYE Lingjiao;ZHANG Dahai;WU Chuanjian;WANG Xueqin;NI Pinghao(School of Electrical Engineering,Beijing Jiaotong University,Beijing 100044,China)

机构地区：[1]北京交通大学电气工程学院,北京100044

出　　处：《电力系统保护与控制》2023年第20期1-13,共13页Power System Protection and Control

基　　金：国家自然科学基金项目资助(国家电网公司智能电网联合基金)(U2066210)。

摘　　要：线路的后备保护在混合直流输电系统中至关重要,但现有后备保护受分布电容和过渡电阻的影响较大,严重影响保护的可靠性和快速性。为解决上述问题,提出一种基于测量波阻抗相位特征的混合三端直流线路纵联保护方案。通过分析混合直流输电线路区内、外故障时线路两端测量波阻抗的差异性,利用S变换提取单频率的电压、电流初始行波,根据测量波阻抗相位差异构造判据区分区内、外故障。PSCAD仿真表明,所提保护方案能可靠快速地识别区内外故障,具有较强的耐受过渡电阻的能力,并且不受故障电阻和分布电容的影响,有效提高了线路后备保护的可靠性和快速性。The backup protection of a transmission line is very important in the hybrid DC transmission system,but existing backup protection is greatly affected by the distributed capacitance and transition resistance.These seriously affect the reliability and speed of the protection.Thus a pilot protection scheme for hybrid three terminal DC lines based on the measured wave impedance phase characteristics is proposed.By analyzing the difference between the measured wave impedance at both ends of the line in the case of internal and external faults of the hybrid DC transmission line,the S-transform is used to extract the initial traveling wave of voltage and current at a single frequency.A criterion area is constructed based on the phase difference of the measured wave impedance for internal and external faults.PSCAD simulation shows that the proposed protection scheme can reliably and quickly identify faults inside and outside the area,has strong ability to withstand transition resistance,and is not affected by fault resistance and distributed capacitance.This effectively improves the reliability and speed of line backup protection.

关 键 词：混合直流输电线路 行波纵联保护 测量波阻抗 相位特征 过渡电阻 

分 类 号：TM721.1[电气工程—电力系统及自动化] TM773