The use of underground cables in transmission and distribution of electric energy is growing. The most commonly installed is the cross-linked polyethylene known as XLPE as an insulator. The XLPE insulation has excellent dielectric properties. However, the XLPE insulator can lose properties prematurely under excessive thermal stress. XLPE cables are designed to operate at 90 oC and 105 oC for emergencies. Temperature limits the current carrying capacity of this cable. This is due to the maximum temperature of the insulating material. Beyond the maximum insulation temperatures, the XPLE insulation ages and consequently breakdown.Thermal stress occurs in the cable is due to the copper losses from the load current and core conductor. These losses occurred in the form of heat. It can be investigated by performing a heating cycle test. The test is implemented by circling enough current through a cable to generate heat to a specific temperature value for a given period. In this thesis, a heat cycle test will be investigated and a model and an algorithm to control the load current to produce a specific conductor temperature given jacket temperature, ambient temperature, bonding, load current, and cable surrounding as inputs will be developed.