A Fault Line Selection Technique for Single-Phase-to-Earth in network grounded with Arc Extinguishing Coil

For the fault line selection of single-phase-to-earth network, the instantaneous characteristic of the arc extinguishing coil is worth expecting. Focused on the transient characteristics in fault line selection technique, the sinusoid adaptive filter (SAF) and the sinusoid approximation of instantaneous signal (SAIS) are adopted in this paper. SAF is used to obtain the grounding moment, while SAIS is applied to obtain the direction and amplitude of the zero-sequence fundamental current when grounding happens. As for eliminating the influence of current transformer (CT) polarity, the compensation feature realized by SAIS is effectively adopted in selecting process. The techniques and methods in the paper have been applied to Chongqing Electric Power Co. for 5 years. In 5 years, hundreds of grounding faulted line has been chosen correctly, 6 wave records of which are shown in the paper.