This paper introduces a proposed technique to calculate reliability indices of interconnected power systems The technique is based upon the sequential path supplementation. state space methods and power low computations. The aspects or component outage reliability data, operating constraints und interconnected power system configurations are taken into considerations. The general steps of the method are : preparation .)ť component reliability data, constructing the reliability data for each subsystem according to the connection of units and ties. Enumerating possible operating paths and formulate path connection matrix, and then state transition matrix according to assumed failure criteria. The application of the proposed algorithm un three different interconnected power systems. shows accurate and valuable results. Also, it reduces the mathematical calculations, because of using path word instead of component word when defining the power system state connection matrix and using network flow to define the condition of each state.
The proposed algorithm is useful in case of planning field, when comparing different plans or alternative designs it is also valuable for operating engineers when they decide to add ties between substations, and it helps them to compare between the location of ties and associated increase in reliability indices.