FIELD: electricity.
SUBSTANCE: invention is used in electrical engineering. According to the method short circuit occurrence is detected and current signals of the short-circuited phase, current signals before short circuiting and signals of zero-phase sequence current are assessed in order to obtain an absolute value of swelling currents (IAB, IBC, ICA) and their maximum value (Imax) against which valid values of short-circuited phase for the indicators (SA, SB, Sc), valid values of three-phase short circuit for the indicators (S3A, S3B, S3C,) and valid value of ground fault for the indicator (SG) are determined, at that the method includes additionally the stages whereat: maximum value of short circuit type is calculated for all indicators (Fflt) as per the following formula: Fmax = max((Fflt)), where the index (flt) is an integer number from 1 up to 10 and stands for one specific type out of all types of short circuit; the short circuit type is defined as one of the indicators (Fflt), where the index (flt) is the type of short circuit; and the indicator (Fmax) of valid type of short circuit is provided to the protection relay (2) or a device connected to the protection relay.
EFFECT: expanded operating performances.
3 cl, 3 dwg
