Early warning of water tree presence in long distance underground cable through extrapolation-comparison method

摘要

The increasing demand for wind energy has called for new facilities to be constructed at locations that require long distance underground cable connections. Many of these facilities, such as offshore wind farms, are located in high moisture environment. For these facilities, high impedance fault such as water tree becomes a potential hazard in cable maintenance, particular in long distance cables. In this paper, a method is proposed for real time monitoring of potential water tree appearance in the long distance cable. The early warning system assesses the possibility of water tree presence using naturally occurring high frequency waves in the system. The response of the high frequency wave is subjected to an extrapolation-comparison method. The early warning system determines if the pulse response contains deviations indicating potential water tree presence. The system process is demonstrated through a 3 kHz pulse. The response for the proposed system is observed.