Desıgn Of Matchıng Impedance And Amplıfıer Cırcuıt For Partıal Dıscharge Measurement

Abstract

Partial discharges are consequence of local electrical stress concentration in the insulation. The
detection of partial discharge at the early stage is useful to predict the condition of the power
equipments. The discharge appears as pulse of duration of much less than one micro seconds. PD
measurements are important diagnostic tools to monitor the insulation condition. Measuring impedance
are used to decouple the PD Current pulses appearing in series with a coupling capacitor to convert it
into voltage pulses for analysis with PD measuring circuit.
The paper deals with design of LCR circuit as matching impedance and as per IEC standard design of
suitable amplifier circuit to amplify signal. The designed circuit is tested observe PD signal appearing
across pigtail specimen inserted in liquid insulator.