Difference Between On-Load Tap Changing and Off-Circuit Tap Changing Transformers
How does the trasnformer realize voltage regulation ?
Transformer voltage regulation is to adjust the number of turns of the coil by adjusting the tap of the transformer side coil (generally on the side of high voltage coil) through a voltage regulating switch (tap switch) to achieve the purpose of changing the output voltage.Transformer voltage regulation is divided into two types: no-load voltage regulation and on-load voltage regulation.
What is no-load voltage regulation and on-load voltage regulaion?
No-load voltage regulation is to disconnect the transformer power first, then adjust the tap-changer, and then connect the power to make the transformer work normally. On-load voltage regulation means that the power supply is not disconnected, and the transformer is provided with a load adjustment tap-changer under normal working conditions.
The difference between on-load voltage regulation and on-load voltage regulation:
The difference is that the no-load voltage-regulating switch does not have the ability to change tap position with load, and the transformer must be powered off when the tap position is adjusted. The on-load tap-changer can switch tap position with load.
Why is it a must to disconnect the power when operating tap position shift through off-circuit tap-changer ?
Because off-circuit tap-changer has a short-time disconnection process during the tap position shift. The disconnection of the load current will cause the arc between the contacts to burn out the tap-changer or lead to short circuit, so the transformer must be powered off when shifting tap position.
What is the advantage of on-load tap-changer ?
- Large pressure regulation range, generally more than ± 10% or even up to 30%
- The voltage regulation speed is fast (it only takes 4 ～ 5s to complete tap position shift, and it only takes 40 ~ 50ms to switch the load), and it is adjustable at any time;
- OLTC can be operated manually or electrically, and it can also be remotely operated or automatically adjusted to facilitate automatic management;
- OLTC is widely used in high and medium voltage power transformers, electric furnaces, electrolysis and other industrial transformers.
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Jiangsu Huachen Transformer co.,ltd.
4 å¹´wow wow??
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4 å¹´What I have noticed is that in Ukraine most of the local designers accept using on-load tap changers to regulate the voltage from wind and solar power plants. I have always been told that it is not a good idea as it requires more frequent maintenance of the transformers. Is this a correct assumption and one should rather use a PPC?