Inductively coupled on-line impedance measurement for condition monitoring of electrical equipment

Abstract

Off-line periodic maintenance has been used to keep critical electrical equipment in good condition. However, there is an increasing demand for on-line condition monitoring of the electrical equipment for preventive maintenance purposes. An on-line impedance extraction technique based on an inductive coupling approach is explored for the detection of early signs of defects of electrical equipment. The proposed method is demonstrated experimentally using a custom-made transformer with emulated defects as equipment-under-test. To enhance the defect detection capability for impedance deviation, various statistical diagnostic indicators are also investigated. By combining the proposed on-line impedance extraction method and a suitable diagnostic indicator, early detection of the defect in electrical equipment becomes feasible.