Why is electricity supplied at high voltage

It can be noted that the power lost at V is much lesser than that at V. Hence for delivering the same amount of power from power station to the load station power loss is much less when it is transmitted at higher voltage. Voltage drop in the transmission lines is proportional to the current flowing through it and its resistance to the current flow. Hence reducing stepping up the voltage and reducing current helps in reducing the voltage drop and improving voltage regulation.

Transmission lines are sized based on the maximum current they must carry. Based on the current area of cross-section of the conductor changes. If an amount of power is transmitted at the lower voltage the size of conductor required is much higher than the same required for power transmission at higher voltages. Hence transmission of power at higher voltages enables a reduction in conductor required for the same. Reduction in conductor facilitates the reduction of conductor cost.

We can improve the efficiency of power transmission by reducing the power losses and cost of conductor and equipment required for power transmission. From the above content, power transmission at high voltage can result in a reduction in power loss and conductor cost, hence improve the efficiency of power transmission. In short, transmission of power at high voltages can help achieving lesser power loss, lesser voltage drops and at the same time improves system efficiency and reduces overall cost of power transmission.

Transformers will only work with an alternating current ac input. This transformer steps up the voltage by reducing the current.

Step-down transformers are used to decrease or 'step down' voltages. These are used when voltages need to be lowered for use in homes and factories. A step-down transformer has fewer turns of wire on the secondary coil than on the primary coil. This transformer steps down the voltage by increasing the current.

To move power around the National Grid: before electrical power leaves a power station — it is transferred at high voltages by using 'step-up' transformers to increase the voltage to around , V before electrical power enters homes and factories — the voltages are decreased by 'step-down' transformers to V The transfer of electrical energy via the grid is very efficient.

The need for a high transmission voltage occurs when a large amount of power has to be transmitted over a long distance. The primary reason that power is transmitted at high voltages is to increase efficiency. As electricity is transmitted over long distances, there are inherent energy losses along the way.

High voltage transmission minimizes the amount of power lost as electricity flows from one location to the next. The higher the voltage, the lower the current. The lower the current, the lower the resistance losses in the conductors.

And when resistance losses are low, energy losses are low also. Electrical engineers consider factors such as the power being transmitted and the distance required for transmission when determining the optimal transmission voltage. There is also an economic benefit associated with high voltage transmission. The lower current that accompanies high voltage transmission reduces resistance in the conductors as electricity flows along the cables.

This means that thin, light-weight wires can be used in long-distance transmission. As a result, transmission towers do not need to be engineered to support the weight of heavier wires that would be associated with a high current.