利用低频故障分量F检验的直流输电线路后备保护新原理  

A Novel Backup Protection Principle for DC Transmission Lines Based on F-Test of Low-Frequency Fault Components

作　　者：张怿宁[1] 张大海[2] 武传健 杨宇辰 ZHANG Yining;ZHANG Dahai;WU Chuanjian;YANG Yuchen(Test&Maintenance Center of EHV Power Transmission Company,CSG,Guangzhou 510663,China;School of Electrical Engineering,Beijing Jiaotong University,Beijing 100044,China)

机构地区：[1]中国南方电网超高压公司检修试验中心,广州510663 [2]北京交通大学电气工程学院,北京100044

出　　处：《南方电网技术》2021年第7期26-33,共8页Southern Power System Technology

基　　金：中国南方电网有限责任公司重点科技项目(CGYKJXM 20180540)。

摘　　要：直流输电技术发展迅速,但其线路保护还存在一些不足,电流差动保护作为后备保护易受线路分布式电容影响而延时较长。为解决直流线路后备保护的长延时问题,本文提出一种基于低频故障电流F检验的纵联保护新原理。该原理根据故障时线路两端故障电流变化趋势的差异,采用S变换提取低频故障电流,并利用F检验对其进行趋势检验,从而识别区内、外故障。利用双端直流输电系统模型实验证明了本文保护原理的正确性,并验证了该原理具有较强的抗过渡电阻、分布电容电流和噪声干扰的能力。DC transmission technology is developing rapidly,but its line protection still has some shortcomings.As a backup protection,current differential protection is susceptible to the influence of line distributed capacitance and has a long delay.In order to solve the long delay problem of DC line backup protection,this paper proposes a new principle of pilot protection based on low-frequency fault current F-test.The principle is based on the difference in the change trend of the fault current at both ends of the line at the time of the fault.The S-transform is used to extract the low-frequency fault current,and the F-test is used to perform the trend test to identify the internal and external faults.Finally,the double-terminal DC transmission system model experiment proves the correctness of the protection principle and verifies that the principle has strong resistance to transition resistance,distributed capacitance and noise interference.

关 键 词：直流输电线路 故障检测 纵联保护 S变换 F检验 

分 类 号：TM721.1[电气工程—电力系统及自动化]