What is a Power Transformer?
Power transformers are electromagnetic components that transmit power, convert voltage, and isolate insulation, and are widely used in power supply and power electronics applications. Power transformers can be divided into several stages based on the size of the transmission power. These stages include high power above 10kVA, medium power between 10kVA and 0.5kVA, low power between 0.5kVA and 25VA, and micropower below 25VA. There is a difference in transmission power, as well as the design of the power transformer.
How does the power transformer work?
Transformers operate on the principle of electromagnetic induction. Transformers with coils shared by their output and input are called special transformers. There are different taps for step-ups and step-downs. There is a reduction in partial tap voltage for less than the common coil. There is an increase in the tap voltage of the part with more than one coil.
The power transformer is a special transformer whose coils are shared by both the input and output. Different taps are used for step-ups and step-downs.There is a reduction in partial tap voltage for less than the common coil.There is an increase in the tap voltage of the part with more than one coil. Induction is the principle that governs the operation of the power transformer. By passing the alternating current through the coil N, we can generate a magnetic field, and a coil M is next to the coil N, because the magnetic field generated by the coil N changes according to the current.With the coil N and coil M having different turns ratios, a corresponding current would be generated in the coil M, whose frequency would change in accordance with the change in magnetic field. Power transformers are now often single-coils (known as auto transformers), and the principle is basically the same.
Structure of power transformers
1.Core
The main iron core materials used in power transformers are iron sheets, low silicon sheets, and high silicon sheets. By adding silicon to the steel sheets, eddy currents and losses can be reduced. Generally, the B value of the black iron sheet is 6000-8000, the low silicon wafer is 9000-11000, and the high silicon wafer is 12000-16000. The quality of the silicon steel sheet has a lot to do with the quality of the power transformer.
2.Transformer winding materials
In addition to enameled wire, yarn covered wire, and silk covered wire, enameled wire is the most commonly used wire. In addition to electrical conductivity, the insulating paint layer should be heat-resistant and corrosion-resistant. In normal circumstances, polyester enameled wire of the QZ model is preferred.
3.Materials for insulation
The coil frame layers and the winding layers of the winding transformer should be isolated by insulating materials, such as phenolic cardboard, polyester film, telephone paper, or yellow wax cloth.
4.Material for impregnation
Generally, cresol varnish can be used as an impregnating material after the power transformer has been wound in order to increase its mechanical strength, improve its insulation performance, and prolong its service life.
Classifications of Power Transformers
1.Small size power transformer
Transformers for small power transformers (SPT) range in power rating from 500 kVA to 7500 kVA.
2.Medium size power transformer
Transformers of medium power (MPT) have a power range between 7500 and 100 MVA.
3.Large size power transformer
Typically, this group consists of transformers with a power rating of 100-200 kVA and above
What are the applications of power transformers?
- Transformers for the generation and distribution of electricity
- High-voltage boosters and buckers
- To reduce the loss of power in transmission systems
- The measurement of voltage and current (e.g. transformers for voltage and current)
- Circuit for controlling the voltage (down to a low voltage of 24,12 volts)
- Industry-specific power transformers
- Power transformers are used on platforms, ships, and submarines
- Power transformers are used in every building and power plant
