A moisture-in-breather model for transformer health monitoring

Breather is an important accessory of the power transformer. Among the various sources, breathing is a major source of moisture contamination in the power transformer. A model for estimating moisture content in silica gel and in the atmosphere inside the breather in different mode of working condition of the power transformer is presented in this paper. The proposed model can predicts the failure of the silica gel in breather, producing abnormal water content inside the transformer. The analysis of the model is based on the equilibrium relations of the moisture concentration between silica gel and environment of breather and the transients that take place until the steady-state equilibrium is reached. The model based on different operating conditions of power transformer was simulated under different standard input signal presenting the moisture variation in the silica gel as input.