Current residue based load independent eccentricity detection in salient pole synchronous machines

In this paper a load independent eccentricity detection scheme based on current signature analysis is proposed. The main idea of the method is to compute the residual current estimates of the fault specific frequency components and eliminate them from the current spectrum of the motor. Such a method has many advantages in addition to load independent detection such as low cost, high sensitivity to detect low level eccentricity faults, minimal hardware requirement etc. Also the scheme is non-invasive in nature and can be employed for online detection. For the first time both stator line current and field current of the synchronous machine have been used independently to diagnose eccentricity. Experiments conducted on a 3 hp salient pole synchronous motor have been used to validate the proposed technique.