Lifetime Estimation of Electrical Equipment in Distribution system using Modified 3-Parameter Weibull Distribution

Lifetime and reliability estimation of distribution system components are very crucial for reliable operation of the distribution system. Reliability of the distribution system depends on the reliability of individual components. The distribution system equipment experiences three different types of failures i.e. infant mortality failures, random failures and aging failures. Infant mortality failures will decrease with time, random failures are induced by the external event and its occurrence is constant and random in nature throughout the life of the component. The aging failures increases with time over the useful lifetime of the equipment due to degradation of electrical and mechanical durability. The impact of aging on electrical equipment is modelled by using the failure history of the equipment. The strength of component reduces due to failures, this phenomenon is considered for lifetime estimation of equipment. This paper presents a 3-parameter Weibull distribution function with varying shape parameter for lifetime estimation. The Weibull parameters are determined by using historical failure data and particle swarm optimization. The proposed model is applied to the equipment of the practical Indian distribution system.