Investigating the Impact of Coil Turns in Flexible Rogowski Coil Sensor for Partial Discharge Detection

Partial discharge (PD) is a prevalent problem in power cables that must be detected early to avert power outages and ensure system reliability. Although numerous Rogowski coil (RC) designs, none of them can accommodate all cable sizes. Thus, a belt-type RC called flexible RC was developed by using Thermoplastic Polyurethane (TPU) for enhanced flexibility. The purpose of this research is to investigate the impact of flexible RC coil turns on the sensitivity and frequency response of the sensor. This study emphasizes the significance of flexible RC sensors in early PD detection for enhanced flexibility and potential benefits for power system monitoring and maintenance. The RC construction is designed in Onshape 3D CAD and 3D printed by using TPU filament. The RC is wounded with various coil turns with the gap distance between coil turns increasing from 0.6 cm to 2.2 cm. The experiment was done by using a signal generator to inject continuous pulses that mimic partial discharge pulses into a conductor. The flexible RC was clamped on the conductor to measure the injected pulses and the result was recorded by using an oscilloscope. According to experimental validation, the sensor sensitivity is quadratically increased with the sensor coil turns while the sensor frequency response is linearly decreased with the sensor coil turns. The findings show that optimization of flexible RC coil turns is important to increase the sensitivity of the flexible RC while maintaining the wide bandwidth of the sensor. The proposed design, characterized by its novelty with TPU materials, yields promising results in terms of flexibility, establishing flexible RC sensors as a feasible asset in power cable PD detection and boosting monitoring and maintenance practices.