What is power transformer in substation?
The transformer is a passive device that is used to change the voltage level. We know well the transformer is an electromechanical static device. It is used to step up and step down the voltage level in a convenient way. However, the electrical transformer is a significant static device in all the generating stations, electrical substations, and distribution centers. It is because we cannot change the voltage level without a transformer. So, the transformer is the heart of the electrical power system. The transformer types in electrical power systems are a common factor. It is because we must require any type of transformer based on the application. However, we will discuss here, what are the main types of transformers that we use in our daily operations in the power sector.
What are the main types of transformers?
The transformer is a highly efficient device in electrical and electronic history. The transformer works on the principle of electromagnetism which is discovered by Michael Faraday. It means a transformer will work on mutual induction or without a conductor. However, we can see the many transformers in our low and high voltage operation. These are created based on the voltage and application. However, have a look what are the main types of transformers. Generally, there are six main types of transformer based on the different factors but these are sub-divided, such as.
- There are two types of transformer based on voltage
- Three types of transformer based on transformer core
- There are two types of transformer based on the transformer windings
- There are two main types of transformer based on the number of phases
- There are two types of transformer based on insulation
There are two types of transformer based on voltage
The types of transformer in electrical engineering can be divided into two main categories relying on the voltage and we use of step up and step down transformer in the high-voltage power sector. Such transformer is the heart of the high voltage power system. These are given below and let’s explain two types of transformer.
- Step up transformer
- Step down transformer
Step up transformer
The step up transformer is used in the power station. It means when the voltage level is changed from a lower level to a higher level (11KV to 132KV or more) such a places step-up transformer is used. The primary winding of the step-up transformer is low (number turn) and the secondary winding is high. It means if we apply low voltage then we will get higher voltage at the secondary of this transformer. But how much voltage we will get will depend on the number of turns.
Step down transformer
The step down transformer is a more useable device on the power system. In most cases, we use of step down transformer for the conversion of high voltage to low voltage. It has high primary winding (number of a turn) and low secondary winding. If voltage is applied to the primary winding then you will get low voltage at the secondary winding based on the number of turns. It means that the transformer voltage ratio depends on the number of turns of the coil. Most of the electrical substations and distribution substations use a step-down transformer. It is because we need low voltage for daily use.
Three types of transformer based on transformer core
The electrical power transformer is a static device that is used to step up and step down the voltage level without changing any frequency. We know that there are different types of transformers based on different factors. However, there are three types of transformers based on transformer core. Let’s see the three main types of transformers based on the transformer core.
- Shell type transformer
- Berry type transformer
- Core type transformer
Shell type transformer
The shell-type transformer is a type of transformer that is used for low voltage or low power and higher output. The shell-type transformer is made of E-type lamination. Shell-type transformer winding is located at the mid-point of the core. It has two magnetic flux paths and requires low copper than berry type transformer. It is noted that shell-type transformer has higher efficiency due to low leakage flux. For this reason, it has higher output power. This type of transformer is used where higher output is required with lower input power.
Berry type transformer
A berry-type transformer is a machine that converts any fruit or vegetable into a berry. The berry-type transformer is an invention that has been in the works for decades. It was originally designed to solve the problem of food wastage and hunger in third-world countries, but it has become popular all over the world as an easy and convenient way to convert any fruit or vegetable into a berry.
Core type transformer
Core type transformer is a type of transformer which has two limbs and two horizontal yokes. This transformer transfer energy from one source to another source through the electromagnetic induction process. This transformer core is made of L shape lamination. It has one way to flow the magnetic flux. Core type transformer requires more copper than shell type transformer. It is noted that core type and shell type transformer is used for high-input voltage and low-input voltage applications. The core type three phase transformer is made up of three limbs in the same plane. In this case, stack lamination is used to build it.
There are two types of transformer based on the transformer windings
We have told you before that there are many types of transformers based on different categories. There are two types of transformer based on the windings, such as
- Two Winding Transformers
- Autotransformer
Two Winding Transformers
Two-winding transformers is also called a conventional transformer. It has two winding and these are coupled with each other but these are isolated and mutual flux is responsible for to transfer from primary winding to secondary winding. The primary winding is connected to the supply system and the secondary winding is connected to the load.
Autotransformer
An autotransformer is a static transformer that has one winding and this winding acts as two windings (primary and secondary winding). The primary winding is connected to the supply line and the secondary winding is connected to the load. The winding of this transformer is connected magnetically as well as electrically. An autotransformer is used to interconnect systems operating at a different voltages. Basically, it is used to regulate the transmission voltage.
There are two main types of transformer based on number of phases
There are two basic types of transformer with name of phases but these are more important in power systems. It is because those are a single-phase load they must require a single-phase transformer and those who have three phase load must require three phase transformer. However, there are two main types of transformers based on the number of phases, such as
- Single Phase Transformer
- Three Phase Transformer
Single Phase Transformer
Single phase transformer is a type of transformer that is used for a single-phase load. This transformer is used as the step-down transformer at the residential load. Single phase transformer is used where a three-phase transformer is not necessary and out power is required for the single circuit such places single phase transformer is used. It is noted that the single-phase transformer has no neutral connection in the winding. It has only no winding on the primary side and another winding on the secondary side and both are separated by the transformer core.
Three Phase Transformer
All transformers are passive electromechanical devices. We are so much familiar with three-phase transformers. It has three sets of primary and secondary windings and each set of the winding wound with a single leg is considered as the primary and secondary winding. Three phase transformer can be a power transformer or high voltage transformer. On the other hand, the entire distribution system has a three-phase transformer with three phases three wires, or sometimes three phases four wires due to neutral wire. It is noted that neutral wire has no relation with transformer windings.
There are two types of transformer based on insulation
Insulation is one of the major factors for all places in the power system. The transformer is a sensitive device that requires high insulation to prevent a short circuit between primary and secondary windings. For this reason, highly refined oil and cellulose (paper) is used. However, there are two types of transformers based on insulation.
- Oil Immersed Transformer
- Dry Type Transformer
Oil Immersed Transformer
Most of the transformers in the power system is the oil-immersed transformer. Let’s see in simple words, what is the oil-immersed transformer. Those transformer windings and magnetic circuits are immersed in oil such a transformer is called an oil-immersed transformer. On the other hand, it is also called an oil-type transformer. This type of transformer is widely used in generating stations, high-voltage substations, distribution substations, and other common places. The oil transformer is an indispensable device in the power system.
Dry Type Transformer
Dry-type transformers are electrical devices that convert low-voltage alternating current to high-voltage direct current or vice versa. It is a type of power transformer that is used in different types of electric equipment and uses a dry type of insulation. The dry type transformer is different from the wet type because the dry type transformer is not immersed in coolant or oil. It has two or three layers of insulation, which are a paper-based dielectric and a layer of mineral oil. As a result, it has a higher voltage rating than the wet-type transformer. On the other hand, paper-based dielectric has a lower thermal conductivity than mineral oil, so it does not require cooling to maintain its operating temperature during operation.
What type of transformer is called step down transformer?
Step down transformer means that the transformer’s primary winding is high but the secondary winding is high. In short, if the transformer’s primary turn becomes high and the secondary turn becomes a low such type of transformer is called a step-down transformer. The use of step down transformer is many places in the power system like grid substations and distribution substations. It means where low voltage is required step down transformer is installed at there.
What do you mean by 3 phase transformer winding?
3-phase transformer windings are 120 degrees apart in phase. The primary and secondary windings are usually connected together through a center tap on the primary winding. The three phases are often marked as A, B, and C. The phase order is usually shown by the lettering on the windings of the transformer and can be found by tracing the wire connections from one terminal to another. A 3-phase transformer has six terminals, three for each primary winding and three for the secondary winding. The terminals are often color-coded: red for A, blue for B, and yellow for C. The most common use of a 3-phase transformer is in electric power generation, grid substations, and distribution systems where it allows utilization of higher voltages.
Final thought
The transformer is a significant and highly efficient device. The transformer is used more in the electrical power system and it is an indispensable device. However, a question comes to our mind what are the main types of transformers. We know that there are many transformers based on different categories. We have referred above that what are the main types of transformer. You may get a clear concept from it. Stay with openread to know more.