SELF TUNING AND COMPENSATING TURN FAULT DETECTOR

摘要

A method for detecting turn faults in an induction motor includes obtaining motor current and voltage waveforms and converting the motor current and voltage waveforms to digitized current and voltage waveforms. Fundamental phasors of the digitized current and voltage waveforms are extracted and, a symmetrical component transform is applied to the fundamental phasors to obtain symmetrical component current and voltage phasors including a negative sequence voltage phasor (V_) and negative sequence current phasor (I_). A fault injected negative sequence current (Ii_) is estimated according to the following equation: Ii_ = I_ - V_/Z_ - Ir, wherein Z_ is a characteristic negative sequence impedance and Ir is a residual injected negative sequence current. The existence of a turn fault is determined by comparing the estimated fault injected negative sequence current with a threshold fault injected negative sequence current.