A Simple Flux-Based Technique to Specify the Faulty Pole of the Salient Pole Synchronous Machines

Abstract

A portable flux probe is proposed and investigated in this article to detect turn-to-turn fault in the rotor poles of the high rated salient pole synchronous machines. The rotor circuit is fed by a low amplitude sinusoidal voltage source with a fixed voltage amplitude which has a frequency more than a few hundred Hz to achieve the higher reaction of the shorted turns on the faulty pole, which results in a significant reduction of the magnetic flux in the air-gap. Numerous simulations and experimental tests are carried out to investigate the proposed probe and the related technique performance to specify the faulty pole versus the number of shorted turns, applied frequency and probable eccentricity in the rotor position. The obtained test results show that all stable turn to turn faults (weak or heavy ones) can be specified easily by applying a portable sinusoidal voltage source with the frequency in the range of more than a few hundred Hz. The experimental test results validate that the flux density can be reduced to about zero in the faulty pole face, even in the case of one shorted turn in the sample machine.