Detection and Localization of Electrical Faults in a Three Phase Synchronous Generator with Rectifier

A three phase synchronous generator with rectifier may be subjected to various electrical faults during its operation. The faults mainly include stator inter-turn short circuit, open and short circuit in the rectifier and open and short circuit in the stator wires. Until present, a lot work has been done to detect and localize stator inter-turn faults (which is the most critical of all the electrical faults), but not much work has been done for the detection and localization of other four electrical faults. Therefore, this paper mainly focuses on the detection and localization of the other four faults. The paper attempts to identify fault signatures in the frequency spectrum that correspond to each of these faults by using the rectified output voltage (measured experimentally) from the generator output. After the identification of these fault signatures, approaches are developed for the detection of faults along with their severity and localization. Two approaches, bandpass filter approach and harmonic magnitude computation using Goertzel algorithm are presented. Both these approaches are able to detect the four electrical faults. With the band-pass filter approach, fault severity can be determined but fault cannot be localized, but with the second approach of harmonic magnitude computation using Goertzel algorithm the fault can be localized. Both of these approaches are applicable over a wide speed range and their effectiveness of electrical fault detection is shown in this paper.