Power Transformer Working Principle

The power transformer is an essential component of the electrical power system, responsible for efficiently transmitting and distributing energy. It is typically used in high-voltage power transmission, from power plants to substations, where it steps up the voltage and reduces current before it is distributed to households, businesses, and other consumers.

The working principle of a power transformer is based on Faraday's law of electromagnetic induction. It consists of a primary winding, a secondary winding, and a magnetic core. The primary winding is connected to a high voltage source, while the secondary winding is connected to the load. The magnetic core is made of iron or silicon steel laminations, which are stacked together to form a closed magnetic path for the magnetic flux.

When an alternating current flows through the primary winding, it creates a magnetic field in the core, which induces a voltage in the secondary winding. The voltage induced in the secondary winding is proportional to the number of turns in the secondary winding and the rate of change of the magnetic flux in the core. The voltage is stepped up or stepped down depending on the ratio of the number of turns in the primary and secondary windings.

The transformer's efficiency is determined by the core losses, copper losses, and stray losses. Core losses occur due to hysteresis and eddy currents in the core, while copper losses occur in the windings due to the resistance of the wire. Stray losses result from the leakage of magnetic flux from the core, which causes heating of nearby materials.