Modeling dependent failures for the availability of extra high voltage transmission lines

An investigation is conducted into the calculation of availability for parallel transmission lines (two or more) in the same tower or on the same right of way. As in many studies, the development of mathematical models is an important step. The models are justified using historical data and known characteristics of power system elements. A statistical method is used to generalize the failure rate from real operating data. Application of the new model (which combines common-mode, simultaneous independent, and dependent outages) is discussed