The new criterion of brushless excitation generator rotor winding inter-turn short circuit fault diagnosis based on reactive relative deviation

In order to find a new online method to identify the rotor inter-turn short circuit fault of brushless excitation synchronous generator, this paper analyzed the changes of electromagnetic properties and electrical parameters and got the fault characteristics that field current increased and reactive power decreased after fault. The relative deviation of generator output reactive power before and after fault has been used for diagnosis and classification of different levels of short circuit. The result is based on both theoretical analysis and experimental verification.