Mobility Compass

• Papailiou, Konstantin O.

Abstract

Overhead transmission lines have formed the backbone of electric power systems over their history of more than 125 years, being at the same time the largest man-made artifacts on Earth. Another peculiarity of overhead lines is that their study encompasses quite a few engineering disciplines, such as electrical, mechanical, civil, and environmental. As system operation issues of lines are covered in Chap.  5 , this chapter concentrates on line components. It starts by explaining the design philosophy of lines, with an emphasis on the calculation of typical line loads, mainly coming from wind and ice, and includes the latest findings on electromagnetic fields ( electromagnetic field (EMF) ) and health. It continues by treating the individual line components, from material selection, manufacturing processes, stress calculations, to special applications. For instance, for conductors, the most costly and important component of a line, emphasis is placed on different types of conductor, their material properties, and what is called their internal mechanics, including sag–tension calculations. However, sufficient space is also dedicated to the ever-important issue of conductor vibrations, thermal rating and monitoring, bundle conductors, as well as new types of conductor. Similarly for insulators, after an in-depth presentation of pollution issues, the focus is on three different types of insulator, i. e., porcelain, glass, and composite. Conductor fittings are addressed next, covering, beside the different types of clamps and joints, also conductor hardware for vibration control, such as Stockbridge and spacer dampers. Line supports, being the most visible component of a line, have seen a significant shift in recent years towards esthetic structures and compactness, while their foundations have benefited from improved designs and new site investigation techniques. The final sections cover construction and maintenance, including new technologies such as robotics, and line uprating and upgrading, the latter reflecting the increasing trend towards augmenting the power transfer capacity of existing lines, as it is not always easy to build new lines. The goal of this chapter is thus to provide the reader with all the basic information required to understand how an overhead line is designed, constructed, and maintained and help in taking the right decisions regarding material selection, the calculation of external loads and internal stresses, and the choice of appropriate standards and testing procedures. Some 300 references facilitate these tasks. Additional information and supplementary exercises for this chapter are available online.

Topics

• machinery
• electric power
• vibration
• monitoring
• composite material
• health
• pollution
• history
• robotics
• modernization
• ice
• foundation
• tension
• economics
• wind
• glass
• electronics
• maintenance
• male
• electromagnetic field
• vibration control
• electronic equipment
• insulating material
• philosophy
• spinal column
• shock absorber
• material selection
• overhead utility line
• clamp

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