Probability approach to installation studies of power transformers

A probability approach to transformer installation studies which have traditionally been based on very conservative deterministic criteria is described. The Monte-Carlo technique is used to evaluate the distribution function of the insulation deterioration with respect to the stochastic nature of load, ambient temperature and emergency loading. A statistical analysis is made to guarantee that a preestablished risk (R₀) associated with the operation is not exceeded. Owing to the fact that the transformer insulation is not regenerative, the concepts of ‘life expectancy’ and ‘rate of insulation deterioration’ are used in order to calculate the permissible peak loads.