ABSTRACT
Power systems are undergoing significant changes in terms of how they are operated, how the electricity is generated and transferred, and how the users interact with the power systems. The purpose of the chapter is to introduce readers to the contemporary energy system issues and challenges, and brief historical perspective of the power system evolution and structure. The generation, transmission and distribution of the electricity is the business of the large utilities, being performed through complex networks of interconnected generators, transformers, transmission lines, control, monitoring, and protection equipment, developed over a century. Coal, natural gas, oil, nuclear energy, water, or renewable energy sources (wind, solar, geothermal energy, etc.) are used to generate electricity in power systems. Power systems are three-phase, from generation, transmission to distribution, the most efficient and economical way to perform its functionalities. Only near to costumers is the power usually changed to single-phase. However, large commercial users are mostly using three-phase. In modern power systems, high-voltages are used for efficient transmission over long distances, and for near end-users, voltages are lowered to the required levels. The smart grids are employing information technology, smart monitoring, control, management, metering and protection, two-way energy and information flows to provide better services to customers and more reliable, resilient, robust and efficient electricity networks.
