Electrical power systems — an overview

This chapter provides an overview of the composition of electrical power networks and of the computer-assisted studies that are used for their planning, operation, and management. The main plant components used in modern power networks are described, and the growing ascendancy of power electronics-based equipment in power network control is emphasized. Such equipment is classified into equipment used in high-voltage transmission and equipment used in low-voltage distribution. The main elements of an electrical power system are generators, transformers, transmission lines, loads and protection, and control equipment. These elements are interconnected to enable the generation of electricity in the most suitable locations and in sufficient quantity to satisfy the customers' demand, to transmit it to the load centers, and to deliver good-quality electric energy at competitive prices. The random nature of the power system load, the ability of a certain class of loads to generate harmonic distortion, and limited capacity to store electrical energy in significant quantities are the issues used to exemplify some of the challenges involved in the planning and operation of electrical power networks. Power networks span entire continents and are never in a steady state condition but rather in a perpetual dynamic state.