Steel and Transmission of Electric Power...

Steel and Transmission of Electric Power  Transmission of electric power is a process by which the electric power produced at power plants is transported in bulk quantities over long distances for eventual use by consumers. The ultimate objective of electric power transmission is to provide power to customers economically, safely, reliably, efficiently, and with minimal environmental impact. Each of these aspects has one or more quantitative measure, such as price per kilowatt-hour, number and lethality of accidents, frequency and duration of service interruptions, generating plant heat rate, transmission and distribution losses, and emissions factors. Transmission systems are designed, and their individual components selected, with all of these objectives in mind, though they may be optimized differently in different systems. Power transmission process has got three main components (Fig 1). They are (i) substations, (ii) transmission poles and towers, and (iii) electricity conductors. Steel plays a major role in all these three components of transmitting power from the point of generation to the consumers. Fig 1 Components of power transmission process Steel use in substations Substations transform voltage from high to low, or the reverse, or perform any of several other important functions. Substation varies in size and configuration. Between the generating station and consuming point, electric power may flow through several substations at different voltage levels. A substation consists of (i) outdoor switch yard, (ii) a building which houses the control equipment, and (iii) the fencing. The outdoor switch yard has (i) structures at dead-end, (ii) static poles, and bus supports and equipment stands. It has also got the grounding arrangement. Structures at dead-end are those structures where the transmission line ends or angles off. They are typically constructed with heavier structural steels in case they are needed to carry heavier tension. The two most common dead-end...