The Application of Zero-phase Digital Filter Algorithm in Transformer Differential Protection
As prescribed in IEC 60044-8 Standard, the rated values of electronic current transformer output data rate can be1000Htz, 2400Hz, or 4000Hz (industrial frequency is 50Hz).In intelligent substations, it is necessary to convert different sampling rates to the same one when intelligent electronic devices of transformer differential protection are connected to ECTs with different sampling rates.This paper studies the sampling rate conversion mechanism with cascade connection of decimation and interpolation to realize sampling rate conversion in rational factor,and the impact on differential protection current is also analyzed.To reduce the group delay of high-order finite impulse response(FIR) in sampling rate conversion, a zero-phase filtering algorithm is designed.Combined that with the decimation and interpolation algorithm, the branch current in any different sampling rate can be converted to the same one, and the seamless connection of differential protection and ECT is realized.Simulation results show that the proposed algorithm can improve the operation speed of differential protection.
ECT Group Delay Sampling Rate Conversion Transformer Differential Protection Zero-phase Digital Filter
Chao Zhu Xinzhi Ding Hao Chen
Jiangsu Electric Power Maintenance Branch Company Yunnan Provinve Electric Power Test and Research Institute Group Limited Jiangsu Electric Power Company, Nanjing China
国际会议
南京
英文
111-115
2015-09-21（万方平台首次上网日期，不代表论文的发表时间）