Distribution Transformer Protection.
A distribution transformer is the type of transformer that performs the final voltage transformation in a distribution grid. They are normally rated less than 200 MVA and the output is usually 3~ 415V/1~ 240V or whatever the service voltage is in the customer's premises. Basic Operating Principle A transformer operates according to Faradays Law of Induction. Faraday’s law states that a current will be induced in a conductor which is exposed to a changing magnetic field. An electric current produces a magnetic field around it. In an AC circuit, the magnetic field produced is constantly changing as a result of current that oscillates back and forth. The primary and the secondary coils are wrapped together around a common “iron core”. This soft iron core is made up of individual laminations stacked together to help reduce the core’s magnetic losses. When alternating current is introduced on the primary coil, the coil develops a changing magnetic field. That magnetic field t