Efficient reduction of fault current through the grounding grid ofsubstation supplied by cable line

摘要

The paper presents an analytical procedure suitable for thendetermination of the part of the ground fault current emanating from thensubstation grounding grid in the conditions when a particular measurenhas been taken to reduce it. The practical realization of this measurencan be simply described as burying one bare copper wire of a certainnlength in the same trench as the cable feeding line. In the case of annoverhead feeding line, the similar measure is denoted in the expertnliterature as the “counterpoise”. The presented methodnenables a quick and, for practical purposes, sufficiently accuratenevaluation of the copper wire length providing the maximum possiblenreduction of the substation grid current. The conveniences of the methodnresult from the simplicity of the formulae for the determination of thenrealized grid current reduction at the effective copper wirenlength