Heat Transfer in High-Voltage Surge Arresters

O. Fritz[1], M. Ljuslinder[2], and B. Doser[2]
[1]ABB Switzerland Ltd, Corporate Research, Baden-Dättwil, Switzerland
[2]ABB Switzerland Ltd, High Voltage Products, Wettingen, Switzerland

We present examples of the use of COMSOL Multiphysics for the solution of electrical conduction in varistors coupled to the solution of long-term heat-transport through conduction and convection. We fit measured power-loss and impedance data with analytic functions in order to simulate instant electric and transient thermal processes in one go.

We systematically compare our results to data from specially performed experiments. Despite the nonlinearity of the conducting medium we can find a good agreement in the observed field distribution and the measured Joule heating. We also investigate the critical parameters leading to possible thermal runaway scenarios. The good agreement between simulations and measurements make design optimizations based on computations a valid option for the further development of high-voltage surge-arresters.