Interdigital Capacitance Sensor for Monitor Ageing of Power Cable – Simulation

Polymeric insulated cables play an important role in electric power transmission especially for energy transfer for offshore windfarms. The assessment of cable status and condition becomes a vital part of energy security. Cable insulation deteriorates over the service period due to the combined thermal and electrical stresses. It is difficult to predict due to variable loadings, therefore, it is crucial to be able to monitor the insulation status of the cables and joints. It has been reported that the interdigital capacitance (IDC) sensor has a potential to measure capacitance and its variation of the cable. In this paper, the performance of IDC sensor has been simulated based a model cable. Different designs were tested and an optimal arrangement was selected to further study the influence of insulation ageing by varying the permittivity of the insulation. It has been found that it is possible to sense the variation of permittivity. Considering the structure of IDC, it may be more useful for the cable joints where the most failures take place in the service.