Reliability Calculations for Dependent Plant Failures

Most of the utility generation planning models make the assumption that outages are independent events. The reason behind this assumption is two- fold: independence allows the calculations to be made using fairly simple algorithms and the utilities have not generally collected data on the effect of outages on system forced outage rates. The Calabrese method of calculating loss of load probability (LOLP) assumes independence of outages. In the popular Baleriaux- Booth algorithm and in the method of cumulants, the assumption of independence is fundamental to the calculation of production costs and reliabiity indices.