DIRECTED DETECTION OF GROUND SHORT-CIRCUIT Russian patent published in 2014 - IPC G01R17/02 H02H3/32 

FIELD: electricity.

SUBSTANCE: method and apparatus for directed detection of ground short-circuit in a multiphase power system is based on comparing change in amplitude or any other normalised value of current of each phase (5_A, 5_B, 5_C). In particular, the average value (m) of the normalised value (|| I_A ||, || I_B ||, || I_C ||) of each phase is compared with each of the normalised values, and depending on the number of times by which the average value (m) exceeds the normalised value (|| I_A ||, || I_B ||, || I_C ||), short-circuit can be determined (L) relative phase current sensors (12). Alternatively, the method and apparatus for directed detection of ground short-circuit in a multiphase power system are based on the variance of coefficients (r_A, r_B, r_C) of linear correlation between phase currents (I_A, I_B, I_C) and zero-sequence current (I₀). Use of these variables enables to determine whether short-circuit has occurred before or after measurement of phase currents (I_A, I_B, I_C) without using another voltage measurement.

EFFECT: preventing erroneous detection of short-circuits in undamaged lines.

15 cl, 8 dwg