Step-up and Step-down Transofmrers in Transmission of Electricity

Transformers are devices in the electrical power grid used to change the voltage of electrical power supply. They are based on the principle of electromagnetic induction.
There are two types: Step-up transformers and step-down transformers.
Step-up Transformers are used to increase the voltage. In these, the number of turns in the secondary coil is more than the number of turns in the primary coil.
High voltages are useful for transmitting electricity over long distances as they reduce energy loss due to heating effect of current. Therefore, step-up transformers are used at power stations to increase the voltage before transmission.
The formula to calculate the transformer action is Vp/Vs = Np/Ns, where V = voltage and N = number of turns in primary (P) and secondary (S) coil respectively.
Step-down Transformers are used to decrease the voltage. Here, the number of turns in the secondary coil is less than the number of turns in the primary coil.
These are generally used at the consumer end, like in homes and industries, to bring the voltage down to a safer level suitable for use.
Energy losses in transformers can occur due to resistance in the coil, magnetic materials not being perfectly insulating, loss due to hysteresis, and electromagnetic radiation and eddy currents. These losses are quite small and transformers can be up to 99% efficient.
In both types of transformers, the power in (Voltage x Current) on the primary side is almost equal to the power out on the secondary side. This means transformers alone don’t affect the amount of energy available.
However, it’s important to remember, while transformers change voltage, they do not change frequency.