Influence of temperature on transformer's winding defect analysis using inductive probes

Abstract

Winding defects change the transformer's winding inductance and capacitance. These deviations of inductance and capacitance reflect in the frequency response of the transformer's impedance. Non-destructive frequency response analysis (FRA) technique has been used for decades to identify these changes. In fact, frequency response of a transformer can be influence by number of parameters such as temperature, oil, humidity, contamination, oil viscosity, degree of polymerization etc. This paper explores influence of temperature on a transformer's on-line FRA using inductive coupling probe approach. Single phase step down transformer is taken. Then the temperature of the transformer is changed for different operating conditions using temperature chamber and frequency response of the transformer extracted for each temperature values using inductive coupling technique. Experiment results are presented and discussed to identify the temperature influence on a transformer's on-line FRA.