Cyclic Temperature Calculations and Measurements for Underground Power Cables

Two time-dependent heat transfer models were developed for calculating cyclic temperature-time profiles for underground power cables with any cyclic load. A fully distributed model allows for temperature variation with radial distance and time in each cable region. A lumped parameter model sets up a thermal circuit and solves for the temperature of each cable region as a function of time. Results from both models are compared with experimental temperature profiles for five cyclic tests for cables in a typical duct bank arrangement. The comparison shows good agreement for cable conductor and jacket temperatures and some error for conduit profiles.