Creative conjugate based characteristics to detect the faulty part in the generator-transformer unit

Abstract

Abstract This study presents an innovative protection method for the generator-transformer zone based on the conjugate concept of the positive sequence component. The traditional protection for such zone employs two relays which generally uses twelve CTs. The proposed method uses one protective relay and utilizes nine CTs (a protective relay and three CTs are saved). The conjugate based innovative method protects the generator and the transformer as one unit and identifies the faulted zone. Such conjugate based inventive protection is based on the building of two relations. The 1st relation is between an adaptive conjugate signal of the neutral-generator current and an adaptive conjugate signal of the generator-transformer current. The 2nd relation is between adaptive conjugate signals of both transformer sides. Various types of external and internal faults, CTs saturation conditions, power swing conditions, and generator startup conditions have been generated by simulating part of the IEEE 9 bus system in the ATP program. The results clearly display the worth of the proposed protection in detecting the various types of internal faults. Other than, the new scheme can accomplish sensible differentiation among generator faults, transformer winding faults, and external faults. What s more, it contributes to encouraging results in the cases of the CTs saturation, power swing, generator startup, generator startup with faults, and different fault parameters. It isn t affected by the type of connection of the transformer. The tripping signal to the generator will be sent in case of a fault inside the generator while the tripping signal to the transformer will be sent in case of the fault inside the transformer.