METHOD OF SELECTION PHASE SQUIRREL AND DEFINITIONS TYPE SHORT CIRCUIT

摘要

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 (I_AB, I_BC, I_CA) and their maximum value (I_max) against which valid values of short-circuited phase for the indicators (S_A, S_B, S_c), valid values of three-phase short circuit for the indicators (S_3A, S_3B, S_3C,) and valid value of ground fault for the indicator (S_G) are determined, at that the method includes additionally the stages whereat: maximum value of short circuit type is calculated for all indicators (F_flt) as per the following formula: F_max = max((F_flt)), 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 (F_flt), where the index (flt) is the type of short circuit; and the indicator (F_max) 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