A model-based segmental ageing location method for underground power cables in distribution grids

Power cable in distribution grids usually operates in nonuniform environments, leading to segmental ageing of cable insulation. Location of segmental ageing is highly desirable for the early maintenance of power distribution grids, which can avoid severe insulation faults and improve system reliability. In this paper, a novel segmental ageing location method based on voltage and leakage current measurements under multi-frequency common-mode (CM) monitoring signal injection is proposed. Segmental ageing models for various types of cables are firstly developed, and a model-based segmental ageing location algorithm is then designed. Comprehensive simulations and case studies in PSCAD/EMTDC are conducted to prove the effectiveness of the proposed method. Compared with the existing approaches, more accurate location of segmental ageing can be realized by the proposed method under various measurement noises, parameter uncertainties and distribution grid structures.