Simulation of Electro-Thermal Runaway and Thermal Limits of a Loaded HVDC Cable

This paper presents simultaneous simulation of interdependent electric and thermal fields inside a dc cable under loaded conditions using analogous distributed circuit models for thermal and electrical phenomena. Certain nonlinearities are integrated in such circuit models, leading to simulation of electro-thermal runaway, for the first time, in a dc cable. Using the suggested, nonlinear circuit models, complete dynamics of the temperature profile and electric field inside the cable dielectric can also be obtained under various test and operating conditions until electro-thermal runaway limits in time domain. The results are useful for design and development of dc cables with safety factors, apart from understanding the electro-thermal limits. The models are validated with experimental results, found to be in excellent agreement.