Investigation on frequency response analysis measurement method for power transformer impedance

The frequency response analysis of transformer has been expected to be a good method for diagnosing the transformer condition. As the transformer impedance is affected by the configuration, the change of the impedance will be a good indicator for the change of the transformer configuration. The method which has been recognized cannot achieve the measurement of current flowing through the stray capacitance to the earth. The measured impedance was not correct at the high frequency range where an influence of the capacitance becomes large. In this paper, the new method was proposed in which the resistor for the current measurement is connected to the terminal of the power application and its value is adjusted. It is shown that the correct measurement can be achieved by the proposed one document.