A probabilistic planning approach to single circuit supply systems

Planning single circuit supply systems has been a challenge for transmission providers for years since the conventional N-1 criterion does not apply. This paper presents a probabilistic planning approach to single circuit supply systems. It is based on historical performance indices, future reliability evaluation and probabilistic economic assessment. A short list of single circuit supply systems for reinforcement is identified first using the criteria of reliability performance (contribution to the improvement of overall system reliability) and probabilistic economic justification. The priority order on the short list is then created using the indices of combined reliability and economic efficiency. The short list with the ranking order provides the essential information for decision makers on the investment direction of single circuit supply systems. An actual utility example is used to demonstrate the application of the presented approach.