Expected Lifetime Evaluation Method and Partial Discharge Progress Characteristics in Capacitor Voltage Transformer

Aged CVTs have been often used in substations, but the expected lifetime of CVTs is unclear, so that it is difficult to determine the appropriate renewal time. Therefore, in this paper, we focus on oil-impregnated paper capacitors inside CVTs and propose a concept to evaluate their expected lifetime based on the partial discharge (PD) progress characteristics. By using a fundamental oil-impregnated paper capacitor model, the PD progress characteristics were measured and discussed from electrical and optical aspects.