method for generating a fault signal that indicates whether an internal transformer failure has occurred and differential protection device to protect a transformer

摘要

patent summary: "method for generating failure signal". The present invention relates, inter alia, to a method for generating a fault signal (st, stneu) that displays whether an internal transformer fault is present. according to the method, a differential current signal (id) indicating the difference between the primary current and the secondary current of the transformer, taking into account the transformer conversion ratio, is guaranteed; a plurality of signals of different criteria (kd1h (n), kd2h (n), deactivated kdc (n), d1d (n), kdcon (n), d2d (n)) is generated using the differential current signal; at least two individual fuzzy logic membership functions (µl, µh, µm) are assigned to each criterion signal; and fuzzy logic pertinence functions are analyzed, thus generating the fault signal (stneu).