The following parts are attached to the three phase power Power Transformer for safety and efficiency.
- Transformer Tank
- Tap Changer
- Explosion Vent
- Buchholz Relay
- Temperature Gauge
- Transformer Radiators
- Transformer Oil
Read the brief information of all these parts below.
1) Transformer Tank
The tank of the Power Transformer is made of iron sheets. It is filled with Power Transformer oil and the Power Transformer (core and windings) is immersed in the oil.
To make the cooling system more efficient for large capacity Power Transformers, the tank of the Power Transformer is made of serpentine sheets instead of straight sheets as the use of serpentine sheets reduces the surface area of the tank. Increases and the heat emitted in the Power Transformer is emitted faster and the Power Transformer stays cool.
L.T. in Power Transformers. And H.T. The ends of the widings are Out from the Transformer. Bushings are fitted to supply it or to supply it. This bushing has a conductor.
Insulation is mounted on all sides around the conductor. Normally porcelain or glass is used for that insulation. Many shades of such insulation are placed around the conductor and the end of the conductor is left open.
Arrangements are made to connect the line conductors by fitting nuts at that end.
3) Tap Changer
The secondary windings of the Power Transformers are tapped for different voltages. This tapings are connected to a rotary switch. Tap switch to such a switch. It is called.
This switch is operated by hand or motor. If at some point the load on the Power Transformer increases, its output voltage decreases. In this case, the tap changer is used to stabilize the voltage by changing the tapping of the secondary with the help of the tap changer.
A long circular tank is connected to the top of the Transformer tank by means of a pipe. This is called a conservator or expansion tank.
The conservator is filled with Transformer oil up to a little more than half the level. The oil level indicator is fitted to the conservator to see the oil level.
When the Transformer is working, the oil heated by the heat becomes lighter and rises and also forms gases due to that heat. The level of oil in the conservator is kept higher than expected so that there is some space to accommodate those gases.
If the oil level is maintained by filling the full conservator, there is a risk that the gas produced by the heat will increase the internal pressure and cause the tank to burst.
The Breather is connected to the top of the conservator by a pipe. A breather is a cylindrical pipe. Its lower end is open. It contains silica gels and calcium chloride in different chambers.
Silica gel is blue in color when completely dry. And if water is mixed in it, it turns white. While the Power Transformer is working, the oil in the Transformer tank diffuses with heat and shrinks due to cold.
So when the heat in the Transformer heats up the oil, it spreads and forms gases. These gases need to go out. And when the oil cools, the contraction of the oil creates an air cavity.
This void needs to be filled. In short, it requires breathing while the Power Transformer is working. This work is done by the Breather. Hence the Breather is called the heart of the Transformer.
When gases are formed in the tank, those gases escape from the conservator through the breather. At that time a cavity is formed in the conservator and the outside air pressure rises so the outside air enters the breather.
The silica gel and calcium chloride in the breather absorb air vapor. And the vaporless pure air fills the cavity created by the conservator.
In short, the main function of a breather is to supply vaporless and oxygen free air to the conservator. When steam is added to the oil, the dielectric of the oil decreases.
And if oxygen is mixed and sparked for some reason, oxidation takes place and oil spheres form. Such oil is not suitable for use. So another chemical is placed in the breather to absorb the oxygen in the air.
6) Explosion Vent
A curved pipe is connected to the top of the Transformer tank next to the conservator. This is called pressure release. At its front end is a thin curtain.
If at any time due to short circuit, overload or any other type of fault in the Transformer, excess heat is generated, excessive gases are produced and due to excess pressure, the curtain on the vent ruptures and all the gases escape.
So the Power Transformer is safe from explosion.
7) Buchholz Relay
This is another factor for the safety of the Transformer. This relay is connected by a pipe between the Transformer tank and the conservator.
This relay consists of two 2 balls floating on oil. Below this ball are the Mercury switches. Under normal conditions, the contacts of both switches are open. The bell circuit is connected to the upper contact.
The bell is connected to the negative end by a battery and the positive end is connected via a switch. The trip circuit is connected to the lower contact.
If the Transformer is in operation, if there is a minor defect in it, the oil heats up and the internal pressure due to the gases increases.
If the fault is of a serious nature (short circuit, overload, earth fault), the lower ball is pushed forward due to excessive internal pressure. So the trip circuit is turned on by adding contacts to its neighborhood. And disconnects from the Power Transformer supply.
this is how the relay works and protects the Transformer.
8) Temperature Gauge
The meter attached to the top of the tank to see the temperature of the Power Transformer is called the temperature gauge. This meter notifies if the temperature rises due to alarm or light.
Transformer Radiators This is the main part of the power transformer. Which helps in keeping the transformer cool. The transformer radiator is connected to the transformer Tank in 2 places as shown in the figure. The radiator transformer is connected to the upper and lower end of the Transfomer Tank by piping through 2 places. Each transformer has the same number of radiators as required.
When the transformer is in service, the hot oil of the transformer tank lightens and goes upwards. This hot oil must be cooled quickly. The cooling of the heated oil is done by the radiators of the transformer. The hot oil passes through the pipe above the radiator into the radiator from where it splits into different blades of the radiator. Most of the radiator blades are exposed to outside air. Because of this, the hot oil reached in the blades of the radiator cools quickly in the blade itself. This cooled oil becomes heavier and goes downwards. This cooled oil transformer again enters the bottom of the stitch through the pipe under the radiator. This action goes on continuously. In this way the transformer is kept cool with the help of radiators.
10) Transformer Oil
It is a mineral oil. But Transformer Oil is popularly known in the market. This oil is a good type of liquid insulator. Of vaporless. Its Dielectric strength 30 to 40 kV. / mm Is. Such oil is filled in the Power Transformer tank and the winding and core are placed in it.
Keeping the Power Transformer cool and acting as an insulator between the winding and the core are two important functions of the aisle.