Novel procedure for low frequency FRA traces interpretation

Abstract

This paper describes a new procedure to estimate separately the magnetization inductance Lm and winding shunt capacitance Cm for each power transformers phase, using and R-L-C electrical equivalent circuit developed to simulate the impedance measured in the Frequency Response Test. The Lm and Cm parameters can be used to analyze the traces obtained in the test. It is also shown experimental results that demonstrate the procedure ability to interpret the FRA traces providing an added value to the graphical comparison. This procedure has a direct application in the FRA based diagnosis because allows failure detection using reliable parameters when the magnetic field of the core is involved.

Detection of Transformer Faults Using Frequency-Response Traces in the Low-Frequency Bandwidth

“…The procedure to estimate separately the magnetization inductance Lm and the winding shunt capacitance Cm, for each power transformers phase was presented in [23]. This contribution is an extension and improvement of that work and describes the procedure to obtain the Lm and Cm parameters from the frequency response and its use in the detection of transformer faults for each phase in the low frequency Bandwidth.…”