Negative sequence current compensation for stator shorted turn detection in induction motors

Negative sequence current analysis is useful for shorted turn detection in induction motors. It can produce fast and reliable monitoring results using a simple measurement technique. However, it is sensitive to disturbances such as sensor calibration, inherent machine asymmetry and supply voltage unbalances. This paper demonstrates an effective phasor compensation technique for these disturbances to allow more accurate shorted turn fault detection. This paper also provides detail investigation of the compensation by demonstrating step-by-step disturbance extraction to obtain the real negative sequence current due to shorted turn faults.