A line selection method of mine leakage protectio

Abstract

Aiming at problem of low accuracy of line selection when single-phase grounding fault occurs in mine power supply system at present, according to characteristics of obvious difference of zero-sequence current waveform between fault line and non-fault line, a line selection method of mine leakage protection based on zero-sequence current integration and improved Bhattacharyya distance algorithm is proposed. Zero-sequence current integral sequence and its probability distribution function are obtained by integrating and recursively processing zero-sequence current data of the first 1/4 power frequency period of each line after the fault. Bhattacharyya coefficient between zero-sequence current integral sequence of each line is calculated by the improved Bhattacharyya distance algorithm, and comprehensive accumulation coefficient obtained by accumulation of Bhattacharyya coefficients is used as fault line selection criterion. In addition, the sum of product of sampled current values of each line at the same time is used as auxiliary criterion to judge bus fault. The simulation results show that the method can significantly increase difference between fault line and non-fault line characteristics, quickly and effectively identify fault line, and is adapt to different neutral grounding modes with strong anti-noise interference ability, little influence by different fault conditions, and high accuracy of line selection.

Keywords

• mine power supply system
• leakage protection
• single-phase grounding fault
• fault line selection
• zero-sequence current integration
• bhattacharyya distance algorithm