A transformer is an undeviating electrical machine that transmits AC electrical energy from one circuit to another at a constant frequency, but the level of voltage can be changed, i.e., on account of the required voltage can be raised or reduced.
It works on Faraday’s principle of electromagnetic induction, which states that the magnitude of the voltage is proportional to the flux change rate.
Distribution transformer
Distribution Transformer manufacturers become accustomed to getting an enormous demand for it. The foremost function of this transformer is to convert inflated voltage to normal voltage such as 240/120 V for use in electric power distribution. There are different types of transformers are available such as underground, 3 phase, pole-mounted, single-phase, and pad-mounted transformer in the distribution system,
Construction of distribution transformer:
The design of the distribution transformer is similar to that of small sized transformers. The main components of this transformer are mainly radiator, pressure relief device, breather unit, oil tank, oil indicator, temperature detector, conservator, thermal relay, butchholz relay and bushing.
- The radiator is used to increase the cooling capacity of the transformer.
- The pressure relief device reduces the pressure inside the transformer to prevent the transformer from exploding.
- The breather unit contains silica gel, which absorbs moisture from the oil. It changes its colour from blue to pink, which is unable to absorb the moisture in the oil.
- The oil tank is used to immerse the windings by installing it inside.
- The oil indicator indicates the amount of oil inside the conservatory unit.
- Temperature detector monitors oil temperature. If the oil temperature rises to a certain level, the transformer will be disconnected from service.
- The conservator is mounted on top of the oil tank outside the transformer frame. It is interconnected to the primary tank with the aid of a metalized tube. The oil inside the tank can be easily contacted and enlarged during loading, thereby increasing and decreasing the oil temperature.
- For the heat of the winding thermal relay is used as an indicator.
- The Buchholz relay is used when the conservator tank is used. This is because it indicates damage when the oil is running low and faults such as oil is not flowing properly between the tank and the transformer.
- Bashing is used to connect the internal windings of the transformer with the serve of an external electric power network.
Classification of distributed transformer:
Depending on the application or requirement, these transformers are divided into three phase, single phase, pole-mounted and pad-mounted transformers.
Single phase –
These transformers are used exclusively for networks that do not require a three-phase supply. Typically, these are used to repair overhead distribution loads in residential areas. This also applies to industrial light commercial loads, lighting and electrical applications.
Three Phase-
This type of transformer is used to store power from the main supply circuit to the short supply circuit. This type of transformer transfers current to the secondary supply circuit and reduces the voltage of the primary supply circuit. These transformers reduce the voltage supply for the main circuit based on user demand.
Pad-mounted-
This type of transformer has a lock steel shelf mounted on a concrete pad. This type of transformer can be installed in areas where there is no space for fenced environments. This transformer is used with electrical power distribution lines in the overhead electrical line to reduce the primary voltage to be supplied to the consumers. This type of single transformer can supply many houses and large building. The power rating of pad-mounted transformer ranges from 75 kV to 5000 kV and consists of fuses and fixed switches.
Pole-Mounted-
These transformers are mounted on the electrical service pole at the height of the overhead cables. These are used to convert high supply voltage to 120/240 volt power. Such transformers are used in wide rural areas from 16 kVA to 100kVA. These are small in size and fit easily in a single-pole structure. These transformers are reliable for extreme weather conditions when used in remote areas.
Applications of distribution transformers:
- This transformer converts high voltage power used in homes and businesses into low voltage power.
b. Its main function is to reduce the voltage to provide isolation between two windings, such as primary and secondary.
c. This transformer supplies electricity to remote areas generated by power plants.
Typically, this transformer supplies voltage less than 33KV in industrial areas and for domestic purposes it distributes 220-440 volts.
Power Transformer
The most important and commonly used transformer is the power transformer. It is widely used to increase and decrease voltage at electrical power generating station and distribution station. In electrical power systems there are many reasons to use a power transformer. The most important and simple reason to use a power transformer is to reduce the power loss during power transmission.
Power transformers are used in high voltage transmission networks. 400 kV, 200 kV, 110 kV, 66 kV and 33 k are the ratings of power transformers. These are typically rated above 200 MVA. Generally installed at transmission substations and generating stations. They are designed for 100% efficiency. They are bigger in dimensions compared to the distribution transformers.
Applications of power transformers:
1. Power transformers are mainly used at distribution stations in electric power generation.
2. It is used in earthing transformers, isolation transformers, wind form transformers, six pulse transformer, converter transformer starters, twelve pulse rectifier transformers and solar PV form transformers.
3. During electrical power transmission it is used to reduce electrical loss.
4. It is used for exorbitant voltage step-up and outrageous voltage step-down.
5. This is a priority in long-distance consumer cases.
6. Where load runs at full magnitude 24×7.
Step-up & Step-down transformer
This type of transformer is classified based on the induced MF and number of turns in the primary and secondary windings.
The step-up transformer converts low voltage and high current AC into high voltage and low current AC system. The number of turns in the secondary winding is higher than the number of turns in the primary winding in this type of transformer. (V2> V1) If the voltage increases at the output point then it is called as a step-up transformer.
The step-down transformer reforms the peak primary voltage associated with low current into low voltage and high current. With this sort of transformer, the whole
Number of turns in the primary winding is higher than the number of turns in the secondary winding. In (V2 <V1) case the voltage drops across the output section and it is recognized as the step transformer.
Instrument transformer
By Industrial Transformer manufacturers they are commonly referred to as isolation transformers. Instrument transformer is an electrical device used to change levels of current and voltage. The most common use of a this transformer is to safely isolate the secondary winding when there is a high voltage and high power supply to the primary so that the measuring device, power meters or relays connected to the secondary part of the transformer are not damaged. Instrument transformer is divided into two categories:
Potential transformer:
A potential transformer is also known as a voltage transformer. The primary winding is connected to the high voltage line, its voltage must be measured and all measuring instruments and meters are connected to the secondary part of the transformer. Constant Voltage Transformers manufacturers mainly produced these. The main function of a potential transformer is to bring the voltage level to a safe value.
Current transformer:
It is used to measure and protect. When the current in the circuit is high enough to be applied directly to the measuring device, the current transformer is used to convert the excess current into the desired value of the current required in the circuit.
The main distribution in the primary winding range of the current transformer is connected to various measuring devices such as ammeter, voltmeter, wattmeter or protective relay coil. They have an accurate, current ratio and phase relationship to keep the secondary side mete accurate. Ratio is very important in CT.
Auto Transformer
Source: exporterindia.com
The autotransformer has only one winding and it acts as a secondary winding. It is lighter, smaller and cheaper than a dual winding transformer and has high efficiency, lower leakage reactance, better quality power and less copper requirements.
Although it is more efficient than conventional, it does not provide electrical isolation for loading from mains and is more prone to faults. This type of transformer can be used to connect windings in different configurations and helps to step-up or step-down the voltage.
Auto transformers are used in railway, audio applications, power transmission and distribution. It is always greater than ‘1’ for the turn ratio of step-up transformer and always less than ‘1’ for step-down transformer.
Step-up Auto Transformer:
Here the total load is connected to the part of the primary winding and to the whole primary winding, source voltage is applied.
Step-down autotransformer: Here the total load is connected to the entire primary winding and to the part of the primary winding, source voltage is applied.
Variable auto transformer:
It is also called as a variance by Variable Voltage Transformers manufacturers, which allows the secondary connection voltage to be switched over a certain range by a sliding brush. This type of transformer is an AC voltage regulator that supplies variable AC voltage to a variety of circuits. Variable transformers increase the voltage output voltage, which is twice as much as the input voltage.
