Rotor Resistance Estimation of an Induction Motor to Detect Broken Bars Fault Using H-H Method

Abstract

This paper presents a new approach, using a new technique we have called “H-H method,” for on-line broken bars detection in induction motors based on rotor parameters estimation from reactive power processing. The hypothesis, on which the detection is based, is that the apparent rotor resistance increases when a rotor bar breaks. To detect broken bars, the processing of reactive power, which is evaluated from the stator terminal measurements, gives by means of H-H method, very quite satisfactory on-line information on rotor parameters evolution. Therefore, the estimated rotor resistance is instantly increased in real time and we can have two values of resistances after and before bar breakage. The proposed method is simpler with a good robustness, and it requires less computing time than the methods based on the observers conducted from induction machine modeling such as the Extended Kalman Filter (EKF) approach. Since it is only based on the reactive power analysis, its main advantage is that it gives always solution on broken bars information even for an unloaded induction motor. Computer simulations, carried out for a 4 kW four-pole squirrel cage induction motor, provide an encouraging validation of the proposed on-line broken bars detection method.