摘要
绝缘监测和故障支路定位是变电站直流系统关注的重点问题,针对传统拉路法、平衡电桥法等检测方法的不足,提出了基于不平衡电桥与小波变换的直流系统接地故障综合检测方法。通过不平衡电桥监测正、负母线对地绝缘电阻,给出了一种综合母线对地电压偏差率和检测灵敏度的电桥参数设计方法。通过选择最优小波基函数对支路电流进行滤波重构,并利用复值小波变换提取信号的幅值与相位信息计算出接地阻值,完成对故障支路的定位。仿真结果表明,所提方法相比傅里叶分析法具有更高的检测精度,并能更好地抑制系统分布电容的影响。
The insulation monitoring and fault branch location are the key problems of substation DC system.To deal with the shortcomings of the detection methods such as pull circuit and balanced bridge,a comprehensive method relating to unbalanced bridge and wavelet transform is proposed.By monitoring the insulation of busbars to the ground with an unbalanced bridge,this paper presents a method which combines bus voltage deviation rate and detection sensitivity to ground.The optimal wavelet basis function is selected to filter and reconstruct the branch current,and the complex wavelet transform is used to extract the amplitude and phase information of the signal to calculate the grounding resistance,so as to complete the location of the fault branch.The simulation results show that the proposed method has higher detection accuracy with regard to the Fourier analysis method,and can restrain the influence of the distributed capacitance of the system to a great extent.
作者
徐以超
聂德宇
顾赟
王书征
XU Yichao;NIE Deyu;GU Yun;WANG Shuzheng(Yancheng Power Supply Company of State Grid Jiangsu Electric Power Co.,Ltd.,Yancheng 224006,China;School of Electric Power Engineering,Nanjing Institute of Technology,Nanjing 211167,China)
出处
《电器与能效管理技术》
2021年第9期78-84,共7页
Electrical & Energy Management Technology
基金
国网江苏省电力有限公司盐城供电公司科技项目(SGJSYC00KHJS2001018)。
关键词
直流系统
接地故障检测
不平衡电桥
小波变换
DC system
ground fault detection
unbalanced bridge
wavelet transform
