Thermal behavior analysis of ZnO polymeric surge arrester using the finite elements method

Surge arresters are used to protect electrical systems against switchgear and atmospheric surges. A defective or bad-dimensioned arrester may cause failures or damage to substation apparatus. Routine and type tests are used to evaluate the surge arrester´s operating capacity. Moreover, one of the techniques used in monitoring and diagnosis of arresters is the thermal imaging. For the correct use of thermal imaging, it becomes necessary to know the acceptable temperatures level of the materials that compose the arrester. Computational simulations have been used to analyze electro-thermal model. This technique presents several advantages, i.e. possibility of previous analyses before the manufacturing and presents lower cost when compared with the tests in laboratory. In this paper, the surge arrester thermal behavior will be analyzed. The surge arrester that was analyzed has a polymeric housing and 120 kV nominal voltage. Tests based on IEC and ANSI standards were computationally simulated using COMSOL Multiphysics^®, which is based on Finite Elements Method. The temperature behavior of the varistor blocks and housing was determined and analyzed.