Electricity is a basic part of nature and it is one of our most widely used forms of energy. We get electricity, which is a secondary energy source, from the conversion of other sources of energy, like coal, natural gas, oil, nuclear power and other natural sources, which are called primary sources. Many cities and towns were built alongside waterfalls that turned water wheels to perform work. Before electricity generation began slightly over 100 years ago, houses were lit with kerosene lamps, food was cooled in iceboxes, and rooms were warmed by wood-burning or coal-burning stoves. “Beginning with Benjamin Franklin's experiment with a kite one stormy night in Philadelphia, the principles of electricity gradually became understood .” However, in present, we use electric power transmission or “high voltage electric transmission” to transfer a bulk of electrical energy, from generating power plants to substations located near to population centres. This is distinct from the local wiring between high voltage substations and customers, which is typically referred to as electricity distributions. Transmission lines, when interconnected with each other, become high voltage transmission networks. In the US, these are typically referred to as “power grids” or just “the grid”, while in the UK the network is known as the “national grid”.
There are many types of power transmission lines and each type carries different functions. Three-phase electric power systems are used for high and extra-high voltage AC (Alternating Current) transmission lines (50 kV and above). The towers must be designed to carry three (or multiples of three) conductors. “The towers are usually steel lattices or trusses (wooden structures are used in Canada, Germany, and Scandinavia in some cases) and the insulators are either glass or porcelain discs or composite insulators using silicone rubber or EPDM rubber material assembled in strings or long rods whose lengths are dependent on the line...
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