Multi-purpose RF antenna for partial discharge and oil quality monitoring

In this paper the possibility to use an RF antenna for both partial discharge (PD) detection and transformer oil quality monitoring is investigated. First, several RF antenna designs such as the dipole, axial helix and circular loop, have been compared to obtain the best optimum design for the detection of partial discharge. It was found that the circular loop antenna has shown the best capability and accuracy of detecting the partial discharge. Then, the selected design has been compared with a commercial acoustic emission (AE) sensor. The RF antenna showed better performance than the AE sensor in terms of high signal to noise ratio and ability to detect PD signal at an early stage. Finally, the RF antenna demonstrated the ability to differentiate between old and new oil samples in terms of their water content and dielectric constant.