Comparative study of continuous distribution models for power system reliability evaluation

The paper presents a generalised expansion method using a gamma distribution as a useful tool for the approximation of capacity outage probability distribution of a generation system. The well known Gram-Charlier expansion and Legendre series are briefly reviewed and compared with the generalised expansion using a sample system IEEE-RTS (reliability test system). The results show that the generalised expansion with a composite of gamma distributions is more accurate and stable than the Gram-Charlier expansion and Legendre series as higher order expansion terms are included.