Deregulated transmission system reliability planning criteria based on historical equipment performance data

In the past, electric utilities were continuously adding more facilities to their systems in order to satisfy the growing customer energy requirements. A utility industry traditionally has relied on a set of deterministic criteria to guide transmission planning. The traditional planning guidelines were based on planner's experience and intuition without a formal and consistent framework for their development. This paper identifies some of the limitations of traditional utility transmission system planning criteria and the possible implications for industrial and commercial customers. The primary objective of probabilistic planning criteria and techniques presented in this paper as opposed to the rules-of-thumb-based planning criteria is to guide transmission system planners in balancing system cost and reliability performance. Contingency ranking has been used as a method of rationalizing system reliability enhancement projects with value-based concepts. This paper presents Alberta Power Limited's criteria review and development of system reliability planning criteria based on contingency ranking and 12 years of historical equipment performance data.