Cable Condition Diagnosis Based on Cable Surface Temperature

Cable condition monitoring techniques play a key role in informing operators of the state of cable assets. Instead of using traditional methods such as partial discharge and dielectric loss measurements, this paper presents a method for cable condition assessment via the measurement and analysis of cable surface temperature. First, the theory underpinning the calculation of cable surface temperature is introduced. Then the cable surface temperature rise in relation to cable dielectric loss is presented. The case of a 275kV oil-filled cable where a local surface temperature rise of 5 °C was observed is also investigated in the paper. Results indicate two reasons possibly responsible for the temperature rise. Finally, the calculations of cable temperature in relation to insulation degradation for 11kV cables show that diagnosis of MV PILC and EPR cables relying on cable surface temperature rise is possible.