A Complete Guide to Transformer Components and Their Functions

Electricity transformers are not as simple as they seem. They contain numerous components to perform complex functions during the safe voltage transformation process. Since multiple functions take place inside, the heat generation is also a risk, which means there must be a mechanism to dissipate it for stable operation. Since we are discussing the components of an enclosed transformer, they will typically include insulators and a heat-dissipating medium, such as oil, inside them. All the elements will lead to a stable voltage transformation.

 

We will break down the entire transformer components, detailing the functions and benefits they provide, as they must receive the current from the incoming source, such as a power plant or transmission lines. Moreover, step-up and step-down operations occur within a transformer; they require components such as coils to adjust the voltage levels according to the requirements. Here are all the transformer components with their functions.

The heart of a transformer is its core. This is where the voltage transformation process takes place. A silicon steel core, located within the transformer shell, generates a magnetic flux to facilitate the flow of electricity. It is the core, which is covered with copper or aluminum winding for the transformation process. It creates a low-resistance path for current to flow along with minimal interference. Different types of transformers feature various core designs. The mechanism and the winding types decide the functions. For instance, single-phase and multi-phase transformers have different kinds of cores. That also makes their transforming range vary depending on the number of windings on them.

 

A transformer core is incomplete without a winding. The number of winds of copper or aluminum wire contributes to the voltage transformation process. The primary winding is in the input area, and the secondary winding is in the load or output area. It facilitates the voltage transformation process, including stepping up and stepping down functions. The primary winding receives the voltage level from the incoming flow, and then the magnetic field transforms it; the secondary winding releases the transformed voltage.

 

Without an insulation system, it is not possible to protect the core from short circuits. Since the primary and secondary coils are in contact, they require insulation to prevent them from reacting with each other. Cellulose or paper-based insulation works inside it due to its non-conductive nature. It covers the copper winding and core to provide electrical, mechanical, and thermal insulation. An insulator provides a stable transformation process by protecting the coil from external influences.

 

Not only do the core and windings need insulation, but some other components also require support. This is where bushings assist in electrical insulation. They provide a safe path for current to flow from the winding to the terminals. Since the current can react with the surrounding components, bushings ensure that such an occurrence cannot happen. They do it by separating the terminals from the tank. Therefore, epoxy resins and porcelain are commonly used insulating materials for bushings. Their insulating nature prevents short circuits and unwanted reactions inside the transformer tank.

 

It is a main shell that houses the core and the winding. The same tank also serves as a heat dissipator to protect the coil from overheating. Since the electric transformation process generates heat, the heat dissipation process is mandatory inside. That’s why the steel tank body provides structural support, heat dissipation, and environmental protection all in one.

 

Moreover, it contains oil for insulation and the heat dissipation process. Since there are two types of transformers, we are discussing the closed type, which includes oil as a heat-dissipating medium inside the tank. It prevents excessive heat generation and short circuits in normal conditions. A transformer tank contains a tiny amount of oil, which is present only for heat dissipation, as excessive oil can make the coils oily and ineffective.

 

There is a backup in the form of an oil conservator tank at the top of the transformer tank. It is a reserve that helps to increase or decrease the oil level in the tank. Weather conditions and temperature variations affect the oil requirements in the tank, which means an oil conservator tank adjusts the quantity for it. This conservator tank has sufficient space to accommodate the transformer's needs. If the temperature inside the tank rises, the conservator tank meets the oil requirements. Likewise, if the oil level exceeds, the excess amount is directed into the conservator tank.

 

Air contains moisture, especially in rainy weather. Even under normal conditions, transformers require air for the heat dissipation process. The only issue that arises is the presence of moisture. That’s why the breather works to prevent moisture from entering the transformer. It is a small component that contains silica gel to keep the incoming air dry. The air that enters the transformer must be dry, allowing the oil and core to remain moisture-free. Any problem with the breather means moisture could enter the transformer, causing short circuits.

 

When a malfunctioning component occurs, overheating begins. Excessive heat can cause the oil inside the transformer to start boiling. An explosion vent at the top of the transformer tank releases the rising pressure inside the tank. It prevents the explosion inside and also protects the tank from rupturing. All it does is allow the pressure to exit through it and reduce the temperature of the boiling oil. An explosion vent prevents severe accidents that can occur due to high pressure inside the tank in extremely hot conditions.

 

A Buchholz relay prevents short circuits and mega failures by shutting down the system. It works only in oil-based transformers. When it detects the gases building up inside because of heat accumulation and oil boiling, it shuts off the system immediately to prevent further damage. To avoid combustible gases from posing a higher risk of explosion, Buccholz's relay must support the explosion vent by shutting the system down. It is similar to the timely release of trapped gases and heat from inside the tank to protect the transformer.

 

Another heat-releasing component is a radiator that absorbs the heat from transformer oil. Since transformer oil must dissipate the heat, the same heat must exit the transformer shell. Radiator or cooling tubes release the heat outside the tank with the help of fans. Without a radiator, it is not possible to perform rapid heat dissipation, as the oil starts boiling when it reaches an excessive temperature. So, radiators keep the oil safe from overheating.

 

The last component is a tap changer, which helps adjust the output voltage. The taps in it allow the operator to change the number of turns in the transformer coil. By adjusting it, operators can increase or decrease the output according to the load requirements. Since there are two types of tap changers, one is an on-load tap changer, and the other is a no-load tap changer. The on-load type allows for voltage adjustments while the system is energized. The no-load tap changer allows changes only when the system is deenergized.

 

An oil-based or closed transformer contains over ten types of components to safely transform the voltage. Moreover, it is not just about the transformation process, but more than that. Rising temperatures, moisture, the safety of components, and protection from explosions require coordination among all these components. Some help in the heat dissipation process, and some help in the stable flow of current from the core to the external components. Likewise, insulators are required to keep the current flow protected from diversion and reactions. All elements contribute to a safe and stable current transformation process that meets the end requirements.