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

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.