The identification of critical equipment and optimum configurations for electrical substationsa

The reconstruction or revitalization of electrical substations provides the possibility to introduce very powerful new switchgears, and as a result, to simplify the substation circuit diagram. Taking into account these tendencies, the authors propose a systematical method for establishing the optimal structure of electrical substations for increasing the operational level of reliability at the lowest economic cost. The graph theory is used to solve this particular problem. A (multi)graph will be associated to the network under study, where the bus system are taken for nodes, while the power lines and the (auto)transformers are considered as branches. By developing this model, the task of finding the critical equipment is reduced to the determination of (multi)graph critical nodes (articulation points) and critical branches (isthmuses). The paper presents an original method that, using the determination of critical equipment (systems of buses, transformers, power lines), indicates the most appropriate (minimal) structure for electrical substation circuit diagrams.