A high-efficiency portable system for insulation condition assessment of wind farm inter-array cables with double-sided partial discharge detection and localisation

Partial discharge (PD) diagnosis is a crucial tool to assess the insulation condition of wind farm cables. Among PD diagnosis techniques, PD localisation is promising as it can provide target maintenance indicators on the insulation weak points of the cables. Accordingly, this paper developed a portable PD detection and location system for wind farm inter-array cables. The system consists of two non-invasive and lightweight testing units, which can be conveniently deployed on an energised cable, enabling highly efficient online PD diagnosis of the widely distributed inter-array cables. The system achieves accurate PD localisation of the energised cable via an improved double-sided travelling wave method. The method exhibits two superior features: the double-sided testing units are accurately synchronised via the joint application of Global Position Systems and a pulse-based interaction process, and a windowed phase difference method is proposed and integrated into the system to robustly estimate the time-of-arrival difference in low signal-to-noise ratio environment. Validation experiments were conducted on both a 10-kV cable in the laboratory and a real 35-kV cable in an on-shore wind farm.