Combined Adequacy and Static Security Considerations in Transmission System Reinforcement

There is growing interest in designing and applying deterministic techniques that include probabilistic considerations in order to assess increased system stress due to the restructured electricity environment. The overall reliability framework proposed in this paper incorporates the deterministic N-1 criterion in a probabilistic framework, and results in the joint inclusion of both adequacy and static security considerations in system planning. The combined framework is achieved using system well-being analysis and traditional adequacy assessment. System well-being analysis is used to quantify the degree of N-1 security and N-1 insecurity in terms of probabilities and frequencies. Traditional adequacy assessment is incorporated to quantify the magnitude of the severity and consequences associated with system failure. A sequential Monte Carlo simulation approach is utilized in this paper for bulk electric system reliability assessment. The combined adequacy and security framework presented in this paper can assist system planners to realize the overall benefits associated with a system reinforcement option based on the degree of adequacy and security, and therefore facilitate the decision making process. Possible reinforcement alternatives for a test system are examined using reliability cost/reliability worth considerations.