Research of Capacitive Strip Partial Discharge Sensor for 10 kV XLPE-insulated Cables

The paper describes research on a capacitive strip sensor for partial discharge (PD) registration in power cables. A metal strip provides a capacitive connection to a power cable because the formed capacitance is a part of the controlled cable capacitance. The sensor equivalent circuit was developed and simulated. Simulation results showed the possibility of the sensor registering partial discharge pulses. After that, the capacitive strip sensor was tested in laboratory conditions. A 10 kV single-core coaxial cable sample was prepared according to the requirements of cable termination. Cable was tested under high voltage and partial discharges were not registered. An artificial defect was created in the cable sample. It caused partial discharges' occurrence under voltage. PDs were registered using commercial PD device with HFCT. The capacitive strip sensor samples prepared of different metals were tested using a calibration generator and under voltage. Experimental results showed that all sensor samples registered partial discharges. However, stainless steel showed the highest pulse magnitude, other things being equal. Therefore, stainless steel is the preferable material to manufacture capacitive strip sensors. However, the wide implementation of sensors is possible after pilot tests using long cables and possible trial operations. Capacitive strip sensors are recommended for permanent installation instead of use included in a portable device.