A Complete Guide On Load Tap-changing Transformers

By Author: Cyrus Joseph
Total Articles: 58
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Load Tap-Changing Transformers is a kind of mechanism that works along with the winding of a transformer and allows several turns before it will be selected on discrete steps. A transformer that has a ratio of variable turns will then be produced which allows for a stepped voltage regulation of the output. Furthermore, the tap selection could be made through automatic means or by a manual mechanism.

Voltage Considerations

If only one Load Tap-Changing Transformers is needed, tap points that are manually operated will be made on the primary voltage or on the current winding of the transformer in order to minimize the handling requirements of contacts. But Auto-Transformers, which come with one winding, may need a tap changer on one of its winding, if there is a need to do so. During the power distribution network, a huge step down transformer might have an off load tap changer on its main winding while the on load tap changer is located on its secondary winding. The high voltage tap matches with the long term system profile that is found on the high voltage network and hardly ever changes. The low voltage tap might ...
... need to change positions several times each day without any interruptions on the power delivery in order to allow for loading condition on the secondary winding network.

On Load Tap Changers

The on load tap changers for a transformer have a significant role to play in the modern power system and even on Auto-Transformers. The reason is because they allow voltages to be maintained at a certain desired level despite of the load changes. In general, the On Load Tap-Changing Transformers is considered a very complex device and in fact, there are cases where the device comes with so many deficiencies. Basically, this kind of device is used to alter the tapping connection of a transformer winding so as to alter the voltage ratio without the need to disrupt the transformer’s operation. The On Load Tap-Changing Transformers come with two major components and that is the diverter switch as well as the tap selector. The tap selector is responsible for choosing the tapping and the electrical contacts that it comes with are designed to bring the rated current of the transformer, without breaking the current. The diverter switch on the other hand, is designed to break and carry load currents on circuits previously chosen by the tap selector.

Off Load Tap Changers

The off load tap changer is also another mechanism in a transformer similar to that of the on load tap changers. However, the off load tap changer only allows the regulation of output voltage by the changes of taps on the transformer, including Auto-Transformers. As the name suggests, this kind of changer suggests that there should be no load that will be connected on the transformer or that the transformer is completely de-energized. Basically, the off-load tap changer is a kind of tap-changing mechanism which can be used only when the transformer was disconnected, unlikely the On Load Tap-Changing Transformers which functions even when the transformer is connected.

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