End-of-life assessment of electric power equipment allowing for non-constant hazard rate – Application to circuit breakers

• Electrical apparatus survival is modeled using statistical methods.
• Associated hazard rate varies with time.
• Results can be used for end-of-life management.

A statistical methodology is proposed for end-of-life studies of aging populations of electric power equipment. As an example, this methodology is applied to Hydro-Québec’s 120- and 161-kV minimum-oil circuit breakers. Non-parametric and parametric statistical methods allowing for a non-constant hazard rate are used to estimate apparatus survival as a function of time since commissioning or manufacturing. This function is then used to estimate hazard rate, mean residual life, mission reliability and life expectancy. This information provides valuable insight for end-of-life management of electric power equipment, which is still usually based on hazard rate estimates independent of age.