Power Transformer Construction

Power Transformer Construction And Winding Connection

The transformer is a high-efficiency electrical device that successfully transfers 95% of total input power to the output. It works continuously to sustain its high efficiency. A power transformer means a step-up transformer. It transfers the electricity from another place by making high voltage from the low voltage alternating current.

The transfer can’t move from one place to another location while it is working. Power transformers look so big with their heavyweight, but the working principle and construction of making it are so simple. This blog will describe the power transformer construction details below:

Types of Power Transformer

According to the basis of construction, there are two types of power transformers. One is a core type, and another is a shell type. Both types of transformers are constructed by the component of the laminated sheet of silicon.

Key Words:

  • Core type
  • Shell type

Power Transformer Construction

The parts of the laminated silicon sheet of transformer look like some English letters. These are E, I, L, and U. We can make many laminated shapes by combining these letters. Insulator wires are turned with the parts of the letter for making a winding.

Core-Type Transformer

The windings of the core type transformers are cylindrical. The lamination steel of E and I are set up together like E-I, the vice versa of two E, and the combination of U-I can make a core type transformer. The one part of the core-type transformer’s primary and secondary windings are twisted outside of the core. A picture of a core-type transformer construction is given below:

Shell-Type Transformer

The fundamental shape of the shell-type power transformer is made of laminated steel L and U. The turns of the coils are twisted inside the magnetic steel core. Shell type transformer looks like a simple rectangular. The fundamental shape of the core-type power transformer is made of laminated steel E and I. The turns of the coils are twisted inside the core.

Parts of a Power Transformer

A power transformer is a significant and weightful device. It builds up with many instrumental parts. Some of them are into the transformer, and some of them are outside of the transformer. To save the transformer it covered with a metal box.

Depending on the purpose and the phases, the power transformer transmits high voltage power from its base station with single or three phases to the distribution center.

According to the cooling system, the power transformers are three types. They are oil-filled, self-cooled, oil-filled, water-cooled, and air blast types (air-cooled). Now consecutively given the information below about the parts of it.

This image will help you to identify the part quickly. The parts of the transformer are marked by text for easy understanding. Below is given another image.

Some important parts of the power transformer are given below with the explanation:

  • Magnetic circuit: Steel is a superconductor of electricity, it is mixed with a moderate amount of silicon to form an alloy used as the transformer’s circuit core. This core determines the direction of the magnetic circuit of a transformer.
  • Electric circuit: The primary and the secondary windings are considered the electrical circuit of a power transformer. The value of it depends on the current flow, voltage, and turn number of the coils.
  • Oil Conservator tank: A oil conservator sets up the top of a transformer. It is used as an extended oil container for a transformer. A transformer tank is filled up with oil. As the oil heats up, its density decreases, and its volume expands. Space is needed for increased volume. The oil conservator manages the space for the extended oil when a transformer gets very hot.
  • Breather: Wind plays a vital role in maintaining the transformer’s heat, and it transmits into the breather. Breather seems to be a heart of a transformer. The breather is connected to an oil conservator with a flexible pipe. When the extended oil comes into the conservatory, a heated wind is disposed of on the breather. And the natural cooled wind comes into the greenhouse.
    With the touch of the air-cooled wind, the hot oil turns into cool. It happens consecutively, and by this method transformer sustains cool. Every time with the breath, air carries moisture, and it eradicates the density of the oil. To solve this problem, silica gel applies to the breather. It isolates the moisture from the air.
  • Insulating oil: A transformer’s tank is filled up with the insulating oil. The primary purpose of the oil is to sustain a minimum temperature among the parts of the transformer.
  • Cooling tubes: Some thick tubes can be seen outside the transformer, in the midst of which oil can be expected to go. As the hot oil passes through it, it radiates heat to the cold air outside and cools inside the transformer. The transformer is cooled naturally through the cooling tube.
  • Buchholz Relay: Buchholz is a part of a power transformer that creates bubbles and excess heat when the transformer falls into a problem. It also works as an alarming system. The bubbles flow towards the conservatory. The number of bubbles shows that how much the transformer falls into the problem.
  • Bushing: Bushing looks like solid porcelain. It enables a safe connection between the wire on the construction of a transformer. When a volume of electrical energy is transmitted into it, it provides an electrical field power to insulate the conductors. There are two types of porcelain. One is oil-filled condenser type; the other is hard porcelain. Hard porcelain type is used in small transformers, and oil-filled condenser type is used in large transformers.
  • Radiator: The transformer works restlessly and creates a maximum amount of heat. So, it is needed to control its temperature. The radiator uses to cool the oil. Radiator attached by the valve with the transformer and it is a detached tube.
  • Explosion Vent: The transformer gets very hot quickly when it works. The solution to the explosion issue was kept in mind during its construction. For averting this simple possibility of destruction, an explosive vent set up the top of the transformer. It minimizes the air pressure inside the transformer. And helps to maintain a standard air pressure both into the transformer and the air.
  • Primary terminal: The primary terminal is the input function of the power transformer. It connects to the low voltage with high current AC source of the power generation plants. The power transformer amplifies the voltage to the secondary terminal.
  • Secondary terminal: The secondary terminal is the output function of the power transformer. It connects to the load. The power transformer delivers the high voltage electricity with the low current in the second terminal for transfer it far.
  • Windings: Windings are very important for a transformer. Because a transformer’s output value depends on the primary and secondary windings in a transformer.

Power Transformer Construction

The construction of a power transformer is straightforward, and it is considered a step-up transformer. The secondary windings are more than the primary windings. The whole of the windings is immersed in insulating oil. A solid iron tank contains the whole parts of the power transformer. The parts are introduced above. Some of the parts are outside of the transformer tank.

Like the radiator, cooling tube, oil conservatory, explosion vent, breather, solid porcelain, etc. Some parts are inside the transformer tank, like the insulating oil, shell, and core-type silicon core, some electrical circuit, etc. All the parts are arranged according to the rule of making a power transformer.

Transformer Core Construction

The core is an important element of a transformer. The primary and secondary windings magnetic flux flows into the core. In the core type, a side of the primary and secondary windings twisted outside the core.

In the shell type, the primary and secondary windings are twisted inside the magnetic circuit core, now given a construction image of a core-type and a shell-type power transformer.

Power Transformer Winding Connection

The transformer windings refer to the working ability of a transformer. In a two-phages step-up transformer, the primary coil turns numbers are less than the secondary coils turn number. Primary windings are connected to the AC source, and secondary windings are connected to the load.

The three phages transformers’ primary windings are connected to the same basis of the two phages. But the discord is it has one more extra connection than two phages.

Summary of the Power Transformer Construction

The power transformer looks like a giant electronic device than any other device in the electronic field. Many parts are combined to make a power transformer. All of it is set up inside and outside the transformer tank. A power transformer is especially used to increase the voltage from low to high and is vastly used in electric power generation stations.


About the Author: Mehedi Hasan

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