An investigation of composite system reliability in meshed and extended networks

Transmission system operators, especially in a deregulated electricity market, are expected to achieve the highest possible reliability levels. The paper addresses the influence that system topology exerts on the reliability of different transmission systems. It is unclear how topological differences between the networks affect system behaviour. This paper first considers the comparative reliability of two different network topologies - meshed and extended - using bulk reliability indices obtained with the composite reliability using state enumeration (CRUSE) software. The results obtained show that a meshed network performs better than a radial network. Extension of the analysis to three realistic test systems reinforces both the significant influence that system topology exerts on network reliability and the difficulty of quantifying differences in network structure. This highlights the difficulties inherent in comparing directly the reliability of different transmission networks.