Partial Discharge Detection, Location and Continuous Monitoring in Power Cable by Using Eulerian Video Magnification

Partial discharge is a common sign of insulation breakdown in power cables, which can eventually lead to serious in-service failures and expensive repairs. In practical, various measurements approaches are used to identify partial discharge problems in power cables. However, these diagnosis technologies either work in off-line condition which needs the cable to be powered off, or need many sensors and supporting equipment to be realized in on-line condition. In this paper, a motion magnification technique is presented, which allows amplified visualization of deformations on power cable caused by partial discharge. Partial discharge defects are manually created on pre-defined locations in an energized 35 kV power cable, whereas a high-resolution camera is used for the video recording in the region of interest. In order to reveal temporal vibrations on cable caused by partial discharge faults, which are difficult or impossible to be seen in videos by naked eyes of human being, spatial decomposition is applied on the video sequence, followed by temporal filtering to the frames. The vibration signal caused by partial discharge, represented by spatial signal in the video frames that drops in certain spatial-frequency bandwidth, can be collected. The resulting signal is then amplified and mapped into reconstructed video frames. Consequently, the small deformations caused by partial discharges on the cable can be identified, as well as the precise locations of the partial discharge defects. Experimental results indicate that errors in locating the partial discharge is in the order of millimeters when the distance between camera and cable ranges from 5m to 10m.