Why we use tap changer in secondary side of transformer?
Answers
The purpose of a tap changer is to regulate the output voltage of a transformer. It does this by altering the number of turns in one winding and thereby changing the turns ratio of the transformer. There are two types of transformer tap changers: an on-load tap changer (OLTC) and a deenergised tap changer (DETC). Note that not all transformers have tap changers.
The purpose of a tap changer is to regulate the output voltage of a transformer. It does this by altering the number of turns in one winding and thereby changing the turns ratio of the transformer. There are two types of transformer tap changers: an on-load tap changer (OLTC) and a deenergised tap changer (DETC). Note that not all transformers have tap changers. An OLTC varies the transformer ratio while the transformer is energized and carrying load. The switching principle uses the “make before break” contact concept. An adjacent tap is bridged before breaking contact with the load carrying tap for the purpose of transferring load from one tap to the other without interrupting or appreciably changing the load current. While in a bridging position (i.e., contact is made with two taps), some form of impedance (resistive or reactive) is present to limit circulating current. A high speed resistive type OLTC uses a resistor pair to absorb energy and does not use the bridging position as a service position. A reactive type OLTC uses a reactor that is designed for continuous loading, e.g., a preventative autotransformer, and therefore uses the bridging position as a service position.
Explanation:
1. Copper losses:- when the transformer is loaded, current flows in primary and secondary winding, there is loss of electrical energy due to the resistance of the primary winding, and secondary winding and they are called variable losses.