ABSTRACT

This research was aimed at to propose a protection scheme for three phase induction motors (IM) in case or phase failure fault. Protection of IM against different possible m ident fault would limit the fault duration and prevent motor under fault particularly for higher motor ratings. Power quality analyzer was employed for characteristic analysis of the functional motor. The results suggested that motor torque increased with corresponding increase in the speed of the motor. In overall terms, voltage imbalance in the range of 5% increased the operating temperature by 50%. The power factor values and displacement power factor were to one which showed the low quantity of harmonic waves. The harmonic distortion was 34.7% with the SCIM running at faulty position either at load position or no­ load condition resulting in the first order harmonic waves being developed. The Phase failure protection (PPP) circuit operated with the excess quantity of current through relay's mechanism, which saved the motor immediately via restarting it automatically with the timer setting in few seconds. The application of proposed PFP scheme proved successful in saving the motor under abnormal condition from the impending failed to it.