Transmission lines are used for the transmission of power over relatively long distances, from powerhouses to the substations
They are long conductors and are made of thick wires. They generate bulk amounts of power at a very high voltage.
Transmission lines have the capacity to bring electricity from one end of the country to the other. In order to do that, interstate connections are used. There can also be transmission lines between countries.
Transmission lines are mostly overhanging lines on high towers about 50 to 100 feet tall or more with a voltage of 1.5 MV or more. These towers are costly to produce so transmission lines are also laid underwater with less voltage.
Transmission lines are bidirectional. The power can go both ways. This distinctive feature helps to balance the power grid.
There are different kinds of transmission lines.
Short Transmission line:
As the name suggests, its length is less than 80km. The voltage is less than 69 kV. Its current leakage is small so the capacitance effect is negligible. Inductance and resistance in the short transmission line are considered lumped. A small transmission line is usually used when the wavelength of the transmitted frequency is short.
A medium transmission line has a length of more than 80 km but less than 250 km. it operates at the voltage of 69 kV to approximately 133 kV. In medium transmission lines, capacitance, inductance, and resistance are equally distributed.
A switch is a component that can interrupt the power or direct it from one conductor to another. It is basically used to impact the conducting path. Switches come with a variety of configurations. They may have multiple contacts controlled by a single knob. Some of them even simultaneously, alternatively or sequentially operate. A switch might as well be operated manually.
Transmission switching has time and now proven to be most beneficial. It is cost-saving, improves the economic and operational efficiency and meets the reliability requirements.
Transmission lines