Designing of Rogowski Coil to Detect Partial Discharge Signals in Power Cables

Abstract

The insulation in any high voltage system is very important component. In case of medium and high voltage power cables, monitoring of the insulation status, partial discharge (PD) diagnosis is necessary to assess the aging degree of the cable insulation, especially for XLPE cable systems. However, owing to noise pollution and attenuation of signal during propagation, the PD signals are weak, which enforce challenges for Partial Discharge detection. Fine detection methods require a sensor with high sensitivity and wide bandwidth to detect the PD pulses. Air core Rogowski coil sensor which is low cost and flexible inductive sensor was designed for PD signal detection in power cables. The parameters of the coil was chosen by drawing bode plots for a lumped parameter model the coil. The optimal damping resistor is selected to get required band width. Amplifier is also used to amplify the output signal from the Rogowski coil. The performance of the designed Rogowski coil was tested in laboratory for different PD signals. The experiment is done on power cable and compared with conventional electrical method. The obtained response of designed Rogowski coil shows nearly better response for a 33 KV power cable. Hence it validates the coil for PD detection in power cables.