Mechanism of Gas Movement and Convergence in Oil-immersed Transformer

Abstract

As a transformer main protection, light gas protection responds to transformer failure solely based on the gas volume within its collection chamber. Such single protection criterion failed to reflect the actual transformer working condition accurately, which have led to protection malfunction or refusal-operation and caused several transformer explosions so far. In order to analyze the mechanism of gas movement and convergence within oil-immersed transformer, an experimental tank with physical structure resembling that of a power transformer is set up, corresponding two-phase flow model is established in ANSYS, simulations of different developing stages throughout the oil-paper insulation breakdown process is conducted. Experiments confirm with simulation results, which state that as fault develops, gas transferred from where the fault occurs, to the upper surface of different structures within the tank; gas generation rate increases throughout time, during which gas exhibits different moving patterns and undergo morphological changes. The purpose of this study is to clarify the gas behavior within oil-immersed transformer based on the moving and converging pattern of gas generated by transformer internal fault.