汾西煤矿35kV变电站接地改造分析

通过对汾西某煤矿35 kV变电所雷害事故进行仔细分析,其主要原因是地网接地电阻超标、均压不完善、以及冲击接地阻抗过高等。经过现场试验、以及结合现场实际情况并且充分考虑煤矿供电特殊性,决定采用铺设冲击接地均压环降低冲击接地阻抗及改善电位分布,利用自然接地体以及敷设GPF-94高效膨润土降阻防腐剂来达到降阻、防腐的目的。改造之后,通过试验论证,各项接地参数均符合要求,达到预期改造效果。

Analysis of Grounding Grid Reconstruction of 35 kV Coal-mine Substation in Fenxi

Through careful analysis on lightning disturbance of a coal-mine 35 kV substation in Fenxi,the main reason is that both of the grounding resistance and the impulse grounding impedance are too high.Field test was carried out and the actual situation is combined with the particularity of power supply in coal-mine,the shielding ring is used to decrease the impulse grounding impedance and to improve the potential distribution.Meanwhile,the grounding resistance is decreased by natural grounding conductors and GPF-94 efficient betonies’ reduction in resistance preservatives.After reconstruction,the grounding parameters are in line with requirements.