FIELD: electronic engineering.
SUBSTANCE: via reverse voltages, amplitude, etc, invention allows to diagnose and locate short-circuit in relation to performance of measurements. Device (100) includes at least one transformer substation (10) of medium voltage/low voltage, which determines transmission line (15) that consists of multiple phase wires (15A, 15B, 15C) of low voltage, means for receiving voltage signal samples of each conductor of transmission line (15) of low voltage, means (110) for preparing samples of signals of phase voltages (VAN, BBN, VCN) of received voltage signals, means (122) for determination of a symmetrical component of reverse voltage (Vi) of transmission line; means (126) for comparison of reverse voltage (Vi) with a threshold value (SD) of actuation.
EFFECT: technical result is to ensure reliable detection of resistive earth fault and/or a wire break in medium-voltage power grid using information related to voltage in low-voltage system.
16 cl, 6 dwg
