Failure rate estimation of power transformers using inspection data

An approach to evaluating the failure rate of power transformers with consideration of inspection and test results is presented. Hazard plotting, a conventional statistical method, is used first to find the best model that fits the aging failure data. Then, by exploring the power transformer's Health Index correlation to age, a method is established to adjust its failure rate based on the evaluated condition. The study of failed and in service units proves the viability of the proposed method.