ABSTRACT

ABSTRACT: The present article presents the results of development of invariant protection against partial single-phase ground faults in the conditions of high non-stationarity of the mining enterprises electric networks. It has been revealed that the current protections in the conditions of single-phase ground faults through transient resistance in the damaged place feature low action selectivity due to significant decrease of operation signals. Functional diagram and algorithm of protection operation providing automatic correction the setting of current for protection functioning according to level of imperfection of singlephase ground faults were developed. Automatic correction of setting of current for protection functioning will provide invariance of protection sensitivity factor in the conditions of varying parameters of zero-sequence circuit, which is proved by modelling results.