device for directional detection of an electrical earth fault, flow indicator for electrical earth fault, electrical earth fault protection relay, method for directional detection of an electrical earth fault and method for protecting a current line

摘要

directional detection of an electrical ground fault. the present invention relates to the method and the device for the directional detection of an electrical ground fault in a polyphase power system which are based on the comparison of the amplitude variation or any other norm value of the currents of each phase (5a, 5b , 5c). in particular, the average (mi) of the standard (iiiaii, iiibii, iilcii) for each phase is compared with each of the said standards and, depending on the number of times the average (mi) is greater than the standards (iiiaii, iiibii, iiicii), the fault can be located (l) with respect to the phase current sensors (12). alternatively, the method and device for directional detection of an electrical ground fault in a multi-phase power system are based on the dispersion of linear correlation factors (r ~ a ~, r ~ b ~, r ~ c ~) between currents phase (l ~ a ~, l ~ b ~, l ~ c ~) and the zero sequence current (l ~ 0 ~). the use of these variables makes it possible to determine whether the fault is upstream or downstream of the measurement of phase currents (i- a, l ~ b ~, l ~ c ~) without using any voltage measurement.