Insulation Failure Prediction Model of Power Cable in Fire

With input parameters being determined, simplified physical model and heat conduction equation were adopted to establish a power cable insulation failure prediction model in fire, and the validation test was carried out. The internal structure of the cable was simplified to a one-dimensional physical model with three layers, to derive the calculation method of internal structure parameters of cable physical model. Differential equation of heat conduction, which could reflect the internal temperature of cable, was constructed based on basic assumptions, to establish a cable insulation cable failure prediction model with mixed layer heat diffusion coefficient, environment temperature change and insulation cable failure temperature as input parameters. The method to determine model input parameters was also proposed. ZR-YJV and SDR-1 cable thermal radiation furnace were selected in the experiments to obtain insulation failure temperature and time, as well as environmental temperature change of the cable. The experimental results showed that the constructed model had relative small error in predicting cable insulation failure time.