DECOMPOSITION APPROACH FOR THE OPTIMAL COORDINATION OF DIRECTIONAL OVERCURRENT RELAYS OF LARGE ELECTRICAL POWER SYSTEMS

ABSTRACT

This paper presents an efficient decomposition technique for the optimal coordination of directional overcurrent relays of large electrical power systems. The large power network is decomposed into number of subnetworks called blocks by identifying boundary buses, branches and relays. The blocks are analysed sequentially and the boundary data table is updated during the solution process. The method reported is distinctly superior to the complete optimal coordination method from the point of view of speed and memory requirements. The results are discussed for the SPC 26-bus and the IEEE 57-bus power systems. The results are also discussed for the 64-bus system of North West India.