FIELD: electricity.
SUBSTANCE: device (10) for detecting the short-circuit direction (7) to ground in the multiphase power system comprises means (14), (14') for receiving signals representing the current of each phase and the zero sequence current (I0), a current signal processing means (30) comprising means (34) for calculating normalized correlation coefficients and means (36) for calculating the average value (μ) and standard deviation (σ) between the calculated correlation coefficients, means for interpreting the results of the signal processing, comprising means for comparing the average value (μ) and standard deviation (σ) to determine if a short circuit is present on the line side or the load side of the device (10). The device (10) further comprises means (20) for storing the values of the residual current signals and the current of each of the phases during the storage period prior to the occurrence signal of the occurrence of a ground fault. The signal processing means (30) comprises means for determining the change in the residual current signal and the current of each phase at a predetermined time that is less than or equal to the storage time, means for calculating a normalized correlation coefficient (34) for calculating the correlation coefficient between the signal change, which is the zero sequence current, and the change in each of the signals representing the phase current.
EFFECT: possibility of determining the direction of a short circuit without using a voltage measurement.
17 cl, 4 dwg
