Introduction to the Problems of Analysis and Control of Electric Power Systems

1.1.1 Electric power can be easily and efficiently transported to locations far from production centers and converted into desired forms (e.g., mechanical, thermal, light, or chemical). Therefore, electric power can satisfy the requirements of a variety of users (e.g., factories, houses, offices, public lighting, traction, agriculture), widely spread around the intended territory. On the other hand, it is generally convenient to concentrate electric power generation into a few appropriately sized generating plants. Moreover, generating plants must be located according to both technical and economic considerations. For example, the availability of water is obviously of primary concern to hydroelectric power plants as well as the availability of fuels and cooling water to thermoelectric power plants. General requirements — about primary energy sources to be used, area development planning, and other constraints, e.g., of ecological type — must also be considered. Consequently, the network for electric power transportation must present a branched configuration, and it can be required to cover large distances between generation and end-users. Moreover, the possible unavailability of some generating units or interconnection lines could force electric power flows to be routed through longer paths, possibly causing current overloads on interconnection lines. These considerations make it preferable to have a network configuration sufficiently meshed to allow greater flexibility in system operation (as an adequate