Mechanical Design of Overhead Lines

Sag in Overhead Transmission Lines

Sag in Overhead Transmission Lines: While erecting an Sag in Overhead Transmission Lines, it is very important that conductors are under safe tension. If the conductors are too much stretched between supports in a bid to save conductor material, the stress in the conductor may reach unsafe value and in certain cases the conductor may

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Corona: When an alternating potential difference is applied across two conductors whose spacing is large as compared to their diameters, there is no apparent change in the condition of atmospheric air surrounding the wires if the applied voltage is low. However, when the applied voltage exceeds a certain value, called critical disruptive voltage, the conductors

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String Efficiency of Insulator

String Efficiency of Insulator: As stated above, the voltage applied across the string of suspension insulators is not uniformly distributed across various units or discs. The disc nearest to the conductor has much higher potential than the other discs. This unequal potential distribution is undesirable and is usually expressed in terms of String Efficiency of Insulator.

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Line Support

Line Support: The supporting structures for overhead line conductors are various types of poles and towers called line support. In general, the line supports should have the following properties : High mechanical strength to withstand the weight of conductors and wind loads etc. Light in weight without the loss of mechanical strength. Cheap in cost

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Introduction to Overhead Line

Introduction to Overhead Line: Electric power can be transmitted or distributed either by means of underground  cables or by overhead line. The underground cables are rarely used for power transmission due to two main reasons. Firstly, power is generally transmitted over long distances to load centres. Obviously, the installation costs for underground transmission will be

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