Often known as a common kind of isolation transformer is a distribution transformer. The key purpose of this transformer is to adjust the high voltage to the standard voltage to be used in electrical power delivery, such as 240/120 V. There are distinct types of transformers available in the delivery chain, such as single phase, 3-phase, underground, pad-mounted, pole-mounted transformers.

I. Construction of Distribution Transformer

Similarly to small scale transformers, the construction of a delivery transformer may be achieved. Oil Tank, Conservator, Buchholz Relay, Breather Unit, Oil Indicator, Temperature Monitor, Pressure Relief System, Thermal Relay, Heater, and Bushing are the main sections of this transformer.

Through inserting it in, the oil tank is used to soak the windings.

On the exterior of the transformer frame, a conservator is located above the oil tank. With the aid of a metallic hose, it is attached to the main tank. During filling, the oil inside the tank can be quickly contacted & enlarged so that the oil temperature can be elevated & decreased.

When a conservatory tank is used, a Buchholz relay is used. And it means mistakes such as oil loss until the oil flow between the tank & transformer falls down, inappropriate.

The Breather Machine incorporates silica gel that retains the oil's moisture. It switches its color from blue to pink, so it is unable to absorb moisture in the oil.

Within the conservatory unit, the oil indicator displays the amount of the oil.

The temperature monitor measures the oil temperature. If the oil temperature rises to a certain amount, it will isolate the transformer from the operation.

To prevent an explosion, the pressure reduction system lowers the pressure inside the transformer.

As a measure of the winding temperature, thermal relays are used.

The radiator is used to improve the cooling efficiency of the transformer.

The bushing is used with the aid of an exterior electrical network to connect the internal windings of the transformer.

II. Types of Distribution Transformer

These transformers are divided into various categories based on the application of necessity, such as single-phase, three-phase, underground, pad-mounted, pole-mounted transformers.

1. Single Phase Transformer

These transformers are particularly used for networks where there is no need for a three-phase supply. These are usually used to repair suburban overhead delivery loads. These are also applicable in applications for industrial lighting, light commercial loads & electricity.

The correct thing is that a single-phase transformer is a transformer whose primary winding and secondary winding are both single-phase windings. Its working principle is as follows:

When a sinusoidal AC voltage U1 is applied to both ends of the primary coil, there is an alternating current I1 in the wire and an alternating magnetic flux ф1 is generated. It passes through the primary coil and the secondary coil along the iron core to form a closed magnetic circuit. A mutual induction potential U2 is induced in the secondary coil, and ф1 will also induce a self-induction potential E1 on the primary coil. The direction of E1 is opposite to the direction of the applied voltage U1 and the amplitude is similar, thus limiting the size of I1. In order to maintain the existence of the magnetic flux ф1, a certain amount of power consumption is required, and the transformer itself also has certain losses. Although the secondary is not connected to the load at this time, there is still a certain current in the primary coil. This current is called "no-load current" ".

If the secondary is connected to a load, the secondary coil will generate a current I2, and therefore produce a magnetic flux ф2, the direction of ф2 is opposite to ф1, which acts to cancel each other so that the total magnetic flux in the iron core is reduced. The primary self-inductance voltage E1 decreases, and as a result, I1 increases. It can be seen that the primary current is closely related to the secondary load. When the secondary load current increases, I1 increases, and ф1 also increase, and the increased part of ф1 just supplements the part of the magnetic flux that is offset by ф2 to keep the total magnetic flux in the iron core unchanged.

To put it simply, it is to convert electrical energy into magnetic energy and then convert magnetic energy into electrical energy. The output voltage is a relative voltage, but there is the voltage between the two wires and no voltage to the ground, which is also called a safe voltage.

2. Three Phase Transformer

This kind of transformer is used from the main distribution circuit to a minor distribution circuit to store electrical energy. This kind of transformer transmits the current to a secondary distribution circuit and the main distribution circuit voltage is therefore decreased. Based on customer specifications, these transformers decrease the voltage supply for the primary circuit.

A three-phase transformer is a combination of three single-phase transformers of the same capacity. It has three core legs, each core leg is wound with two coils of the same phase, one is a high-voltage coil and the other is a low-voltage coil. A three-phase transformer is a generator that generates an electric potential of equal amplitude, equal frequency, and 120° phase difference, called a three-phase generator; a three-phase generator as a power source is called a three-phase power supply; a circuit powered by a three-phase power supply, It is called a three-phase circuit.

U, V, W are called three-phase, the voltage between the phases is the line voltage, and the voltage is 380V. The phase between the phase and the center line is called the phase voltage, and the voltage is 220V. The working principle of the three-phase transformer: the basic work of the transformer The principle is the principle of electromagnetic induction. When the AC voltage is applied to the primary winding, the AC current flows into the winding to generate excitation, generating alternating magnetic flux in the iron core. This alternating magnetic flux not only passes through the primary winding but also through the secondary winding. It causes induced electromotive force in the two windings respectively.

3. Pad-Mounted Transformer

A locked steel cupboard that is arranged on a concrete pad contains this kind of transformer. In areas where a fenced enclosure does not have space, this sort of transformer is mounted. This converter is used to decrease the main voltage to provide consumers with electric power delivery lines on an overhead electricity grid. Many homes/large buildings may be powered by a single transformer of this kind. This transformer's power level varies from 75 kVA to 5000 kVA and includes fixed switches & fuses.

4. Pole Mounted Transformer

At the height of the overhead cables, these transformers are mounted on an electrical utility pole. These are used to change the high distribution voltage to low power of 120/240 volts. In vast rural areas, these types of transformers are used, varying from 16 kVA to 100 kVA. These are available in limited sizes and are easy to install on buildings with single poles. These transformers, when used in rural areas, are reliable in harsh climates.

It is possible to structure and protect the transformer tanks from corrosive materials and water accumulation. Tanks should be covered from zinc spray in coastal environments, while stainless tanks are used in highly corrosive regions.

III. Applications of Distribution Transformer

Below are the applications of the distribution transformer:

• This transformer, used in homes & enterprises, switches from high voltage electricity to low voltage electricity.

• The key purpose of this is to decrease the voltage and provide insulation between two windings, such as the primary and secondary windings.

• This transformer distributes the power generated by power plants to remote areas.

• In general, this transformer distributes electrical energy for domestic uses to factories with lower voltages below 33 KV and 440 volts to 220 volts.