Basic Study on Partial Discharge Detection with High Sensitivity using Ferrite Core

Recently, deterioration of insulation in power equipment such as power cables due to partial discharge (PD) can give rise to crucial accident in power systems. To prevent serious failures in power equipment, on-site monitoring and early PD detection is important. In the present study, a new PD detection method using ferrite core (FC), which is inexpensive and easy to install, is proposed. FC is generally used to remove high frequency noises using its resistance component increasing with the frequency. As basic study on PD detection with various kinds of FCs, the frequency dependence of impedance was investigated. As a result, FC was found to provide much higher PD detection sensitivity than a high frequency current transformer (HFCT). The number of FC installed and its type were also found to give a great influence on the sensitivity and frequency band in PD detection. In conclusion, it was shown that FC is applicable for PD detection in power equipment.