A Novel Method to Discriminate Inrush Current from Internal Fault Based on Primary and Second Harmonic Energy

2019 4th Asia Conference on Power and Electrical Engineering

能源学;电工学

Shen, Hongming^1 ; Liu, Ying^1 ; Chen, Wei^1 ; Zhang, Xianglong^1 ; Du, Na^1

State Power Economic Research Institute Co., LTD, Beijing

102209, China^1

关键词: Attenuation characteristics;    Attenuation factors;    Energy concept;    Fourier algorithms;    In-rush current;    Internal faults;    Second harmonics;    Transformer differential protection;   

Others  :  https://iopscience.iop.org/article/10.1088/1757-899X/486/1/012018/pdf
DOI  :  10.1088/1757-899X/486/1/012018

来源: IOP

【 摘 要 】

To discriminate inrush from an internal fault is a hot topic, as the inrush current may cause transformer differential protection to malfunction. Compared with Fourier algorithm, prony analysis can get amplitude and attenuation factor of one signal. Thus, prony analysis may have a better effect in discriminating inrush current. First, the energy concept of primary and second harmonic is first proposed based on prony analysis in this paper. Then, according to the study of attenuation characteristics of fundamental and second harmonic, it is found that the ratio of fundamental energy to second harmonic energy has a big difference in inrush current and internal fault. Thus, a novel method based on primary and second harmonic energy is presented. Simulation results of PSCAD prove the method to be correct.