摘要
在文 (一 )的基础上 ,详细分析了输电线路内部、外部故障时暂态电流的特征 ,发现内部故障时第一个行波电流的波头陡度大 ,并且其后的部分含有高频分量 ;而区外故障时第一个行波波头的陡度较小 ,且其后的部分高频含量少。利用不同尺度小波变换模极大值的比率可以提取波头陡度的差异构成保护判据 1;利用小波的带通滤波器特性可以提取高频分量 ,构成保护判据 2。仿真计算结果表明 ,保护判据的正确性不受故障类型、距离、初始相角的影响 ,与工频量保护不同的是 。
On the basis of patr one, the characteristics of transient current waveform respectively induced by in area and out area faults are analyzed in detail. It is found out that the gradient of the front traveling wave caused by in area fault is higher and it contains more high frequency components than that caused by out area fault. The first protection criterion can be extracted by calculate the ratios of the maximum modulus using wavelet transform at different scales and the second protection criterion by using the band passing characteristics of wavelet. EMTP simulation shows that fault type, fault location and fault inception angle do not influence the correctness of protection criterion.Contrasting with power frequency protection, the bigger the fault resistance is, the higher the protection sensitivity becomes.
出处
《电力自动化设备》
EI
CSCD
北大核心
2001年第7期1-6,共6页
Electric Power Automation Equipment
基金
中华电力基金许继奖教金课题资助金资助项目
关键词
超高压输电线路
单端暂态量
小波变换
速动保护
电流互感器
non unit transient protection
wavelet transform
singularity detection
high frequency component
