Basic models and methodologies for common mode and dependent transmission outage events

This paper presents a brief summary of the basic common mode failure models and the relevant equations for their inclusion in power system reliability studies. The basic differences in the models are illustrated by numerical examples. Models for incorporating transmission outages associated with enhanced failure rates due to adverse weather are also illustrated. These models are combined with common mode events in a numerical analysis to illustrate the relative effects of common mode failures and failure bunching due to adverse weather. Concepts associated with dependent outages are discussed with particular emphasis on station related transmission outages.