OLTC Distribution Transformer

On-load tap changer (OLTC), also known as On-circuit tap changer (OCTC), is a tap changer in applications where a supply interruption during a tap change is unacceptable, the transformer is often fitted with a more expensive and complex on load tap changing mechanism.The primary of this transformer is supplied from a regulating transformer fitted with on-load tap-changing gear. The booster transformer is connected in such a way that its secondary injects a voltage in phase with the line voltage. The voltage at AA is maintained constant by tap-changing gear in the main transformer.A three-phase transformer is made of three sets of primary and secondary windings, each set wound around one leg of an iron core assembly. Essentially it looks like three single-phase transformers sharing a joined core as in Figure below. Three phase transformer core has three sets of windings.transformers are passive machines that pass electrical energy between circuits. In the secondary circuit, a magnetic flux induces an electromotive force (emf), thus stepping up (increase) or stepping down (decrease) voltages without altering the frequency.Ideal for power distribution, three phase power transformers are best for electrical systems that require efficient distribution capacity and high-power transmission capabilities.