Abstract: The present invention relates to a method of diagnosing a fault on a transformer winding by using frequency response analysis. The method comprises the steps of: measuring the impedance on said winding as a function of frequency, said measurement being represented in the form of a first voltage gain; comparing said impedance measurement with a reference measurement represented in the form of a second voltage gain, said comparison including a step of calculating three first parameters, each of said three first parameters being a correlation coefficient, between said first and second gains over three different frequency ranges. The method further comprises a step of determining the relative variation of at least a fourth parameter, said fourth parameter being a physical magnitude characteristic of said transformer, said relative variation being obtained by comparing said first and second gains.

Abstract: This invention relates to a method of diagnosing one fault on a transformer winding using a Frequency Response Analysis (FRA). This invention is adapted more particularly to power transformers. The method comprises the following steps: measure the impedance of the said winding as a function of the frequency, the said measurement being represented in the form of a first voltage gain k, compare the said impedance measurement with a reference measurement represented in the form of a second voltage gain k?. The method also comprises a step to determine the relative variation of the first resonant frequency exceeding 10 kHz, the said relative variation being obtained by comparing the said first and second gains k and k?.

Abstract: The present invention relates to a method of diagnosing a fault on a transformer winding by using frequency response analysis. The method comprises the steps of: measuring the impedance on said winding as a function of frequency, said measurement being represented in the form of a first voltage gain; comparing said impedance measurement with a reference measurement represented in the form of a second voltage gain, said comparison including a step of calculating three first parameters, each of said three first parameters being a correlation coefficient, between said first and second gains over three different frequency ranges. The method further comprises a step of determining the relative variation of at least a fourth parameter, said fourth parameter being a physical magnitude characteristic of said transformer, said relative variation being obtained by comparing said first and second gains.