by on March 15, 2019
The actual design of a transmission structure not only involves checking the strength and suitability of various components, but also ensuring that all materials and components meet the requirements of the governing standards or codes. Important items such as grounding are also a part of final structure design configuration and are briefly reviewed.   1-) Strength Checks The following sections cover code-mandated design checks for wood poles, steel poles, lattice towers, concrete and co...
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by on March 12, 2019
This section deals with the theoretical basis for analysis procedures for various transmission structure forms and types. Computer programs such as PLS-POLETM and TOWERTM are generally employed by most utilities; some utilities also have their own in-house programs for structural analysis, in addition to general purpose finite element programs. However, it is important to understand the underlying basis and limitations of these programs. The basics of analysis of various systems will be illustra...
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by on March 5, 2019
The design of transmission line structures involves both analysis of the structural system – wires, supports and foundations – as well as design checks ensuring compliance with established norms and guidelines. Worldwide, most countries have institutions and standards devoted to design, construction and safe operation of utility structures. These standards or codes cover a variety of parameters such as loading, conductors, materials (steel, wood and concrete), hardware, clearances, performance a...
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by on February 22, 2019
Historically, the term “transmission structures’’ usually implied iron or steel latticed towers. The early “pylons’’ dating back to 1829 were iron structures; the basic shape of later pylons was mostly inspired by the famous Eiffel Tower. Figure 1.1 shows some of the early shapes and forms of transmission structures. Single wood poles directly-embedded into the ground formed the bulk of the transmission structures family for a greater part of the 20th century. France in the late 1900s and...
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by on February 21, 2019
   Count Alessandro Volta (1745−1827), the Italian physicist and inventor of the battery, was the first person to suggest the idea of a transmission line by writing in 1777 “… the igniting spark could be transported from Como to Milan with barbed wire supported by wooden poles planted here and there …’’ The structures in use those days for telegraph poles were wooden poles with zinc iron barbed wire supported by porcelain insulators fixed to the pole with screws and bolt hooks (TERNA, 2013). The...
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