Voltage Electric Transmission

Here, the voltage is reduced by using a number of step-down transformers as for domestic purposes we use the voltage of 220 Volt and 50 Hertz frequency. In the voltage electric transmission for the long distances, the loss of power in the transmission lines is I²R, where I is the electric current that flows through the wires and R is the resistance of the transmission wires. To reduce the power loss in voltage electric transmission, we transmit the voltage at extremely high voltage. This will reduce the value of electric current in the same ratio. Thus, the value of I²R becomes negligibly low because here I become very small while the resistance R is high. This means that we can use thin wires instead of thick wires which having the high resistance. This also saves the material used to make the transmission wires. This method of the voltage electric transmission also reduces the cost of transmission.

There are two modes of electric voltage transmission.

(i) Overhead Electric Voltage transmission

(ii) Underground Electric Voltage transmission

(i) Overhead Electric Voltage transmission:

In overhead electric voltage transmission, the overhead conducting wires or cables are not covered with insulated materials. The conducting cables are mainly made up of aluminium alloy. Sometimes we use copper for making the conducting cables for voltage electric transmission. However, due to the lesser the density of aluminium, the weight and the cost of aluminium alloy is less so generally we prefer aluminium alloys. The area of the conducting wires is ranging from 12 mm² to 750 mm². The current is A.C. in nature for electric voltage transmission. So due to the skin effect it always flows through the surface of the conducting wires. Since, in overhead voltage electric transmission, the wires are uninsulated so they are quite unsafe.

(ii) Underground Voltage Electric Transmission:

Voltage electric transmission can also be done by underground transmission instead of overhead power lines. Underground electric voltage transmission can be done in densely populated areas, land whose value must be maintained for future, areas of infrastructural developments, etc. Underground voltage electric transmission have several advantages such as: less damages in the wire line in case of drastic weather conditions, take less space for installation of wires, safe for the wild life creations so that there are no shock hazards, less chances for conductor theft and illegal connections, etc. Underground voltage electric transmission also have some disadvantages such as it is more expensive, takes lot of time to find the fault in the wire lines and cannot be maintained life due to proximity of earth, etc.