Transformer types Depending on the Use or Application
We shall cover various transformer types in this article in accordance with their applications. The data is as follows:
1-Power Transformer, Industrial, Step-Down, EHV, UHV
Industrial power and distribution step down Transformers are utilized in many different fields to change the output current and voltage in a supply circuit without changing the total power. Transformers are used in power transmission to increase or change the input voltage of a power source, allowing for relatively low-loss energy transfer over long distances.
After that, the voltage is stepped down in preparation for distribution. Power networks often use power transformers, typically with ratings exceeding 250 MVA, for power transmission system and distribution systems.
IEC 60076-1-2011 / IEEE C 57.12.00-2015; C57.12.10-2017/ IS 2026 (Part 1):2011 Power Transformers
2-Low voltage and high voltage Distribution Transformer
However, the most common type of isolation transformer is a distribution transformer. This transformer’s primary job is to convert high voltage to a low voltage, like 11,000 to 415 volts, for use in power distribution. In the distribution system, there are different kinds of transformers, such as single-phase, three-phase, underground, pad-mounted, and pole-mounted.
Most of the time, these transformers come in different sizes, efficiencies, and types of insulating oil. There are various sizes and levels of efficiency available for these transformers. The user’s needs and budget have a major role in the transformer’s selection. Connections for distribution transformers can be made in four different vector group configurations, including star-star, delta-star, star-delta, delta-star, and zigzag/delta-zigzag.
IEC 60076-1-2011 /IEEE C57.12.36-2017/ IS 1180(part 1)-2014
3-Voltage-regulated distribution transformers.
With most distribution transformers, a high-voltage tap-changer is used to choose a transmission ratio that works best for where the transformer is installed. By selecting an acceptable transmission ratio, the voltage in the entire linked LV grid can be kept within the permitted voltage limits.
The de-energized tap-changer is installed and rarely has to be modified, in particular in reaction to altered grid conditions. So, for most distribution transformers, tap-changers are DETCs, which can only be turned on when the transformer is turned off.
The Voltage Regulating Distribution Transformer (VRDT), which can be turned on manually or automatically when on-load and powered, was made possible by the fact that customer-oriented voltage regulation can sometimes help keep voltage stable, especially as the structure of power generation and use changes more quickly than ever before. No matter what technology is used to make it or how it works, a VRDT usually has three parts: an active transformer, a controlling component, and a control unit with regulation.
IEC 60076-24-2020 Voltage Regulating Distribution Transformers
4-Generator step-up or a generator transformer Unit Transformer for Thermal, Hydro, Nuclear, and Pumped Storage Hydro in the USA
Generator transformers are the transformers that are directly connected to the generator to increase the voltage for transmission. The producing transformer does not always need to have three-phase or single-phase windings. It is based on the generator’s MVA rating. Generator transformers are used on thermal plants, hydro plants, nuclear plants, and many others.
5-Station Start-up Transformer—Station Service Voltage Transformer
In general, a station transformer is a step-down transformer, which reduces the voltage, as opposed to a step-up transformer, which raises it by default. This dynamic ensures that residences get the proper amount of power, with the step-down transformer reducing it to a level that is more manageable for the typical building.
If there was no way to regulate it, the electricity system would supply too much voltage to buildings, which is easily overheated and can damage electrical equipment. This alone demonstrates the importance of a station transformer since it makes it possible for residential areas to consume power in a controlled and efficient manner.
Transformers directly connected to Generators: C57.116-2014 Guide
6-Unit Auxiliary Transformer, manufactured in the United States
Electricity for auxiliary loads at a producing station is provided by auxiliary transformers ( battery charging, feed pumps, a control panel, cooling pumps, and protection devices that a power plant needs to operate). There are a few different auxiliary transformer types to remember, but thankfully there are more acronyms to make things simpler.
A unitary auxiliary transformer, which steps down voltage to serve the auxiliary power system buses, is linked to the same bus as the generator. The UAT is always providing the auxiliary load while the generator is operating.
A backup transformer linked to an offsite high voltage system, the reserve auxiliary transformer or starting auxiliary transformer provides supplemental power to the plant during startup or interruption periods.
7- Auxiliary transformer for substations
Auxiliary transformers are used to provide low voltage for the substation’s AC power system, which includes the lighting load, air conditioners, AC and DC fans, and other AC and DC supply systems, as well as the DC power system, which includes SCADA and telecom, intercom systems, batteries for charging, protection relays, and other DC supply systems.
8- A grounding (or earthing) transformer
It is a unique transformer that offers a return route for an earth fault on a transformer connected to a transmission and distribution delta line.
9- The track-side transformer (traction supply transformer)
The main grid’s high supply voltage (33KV to132KV or 220 kV) must be stepped down to 11 kV by the traction transformers. The traction transformers are carefully designed to have a high short-term peak capacity and be able to tolerate challenging operating conditions
EN 50329-2003, IEEE 1653.1-2016, and IEC 62695 ed1.0-2014 Transformers for traction and power rectifying in fixed installations and substations
10- Locomotive Transformer (Traction Transformer): roof-mounted and vertically positioned beneath the frame.
The dc supply necessary for the motors used by the railway locomotives is stepped down using the loco transformer. The dimensions and weight of this transformer are quite reasonable. By placing the active component horizontally, the height of the device is decreased.
IEC 60310 ed4.0-2016 Traction Transformers and Inductors
11-The booster transformer
Booster transformers are often installed at the ends of transmission lines in order to raise the voltage to the appropriate level. It regulates the voltage of a feeder located far from the grid station’s main transformer. The primary of the booster transformer is powered by the secondary of the regulating transformer, whose winding is linked in series with the transmission line.
The main input winding of the booster transformer is connected to the secondary output winding of the regulating transformer. This ensures the injected voltage is in phase with the supplied voltages. By adjusting the taps on the regulating transformer, both the amplitude of VB and the voltage entering the circuit may be altered.
Only a minor portion of the rating of the regulating transformer is affected by the rating of the primary transformer. suggested by the term.
12- Electric arc transformers (furnace transformers)
A furnace transformer, also called an arc transformer, is a tool or device that changes the voltage of alternating current (AC) so that it can be used in your heating furnace. It moves electrical energy from one circuit to another using electromagnetic induction.
In a furnace, the main job of a transformer is to change the input voltage so that it meets the needs of the system. Depending on how much power the furnace needs, the transformer may cut or raise the amount of electricity used. The transformer is normally found within the furnace in HVAC systems, but sometimes it may be found in the outside air conditioning unit.
Furnace Transformers, IEEE C57.17-2012 / IS 12977-1990
13-Welding Transformer
Welding transformers are required in electric machines to transform the power line’s alternating current into a secondary coil current with a low voltage and high current. A pair of primary and/or secondary taps on the welding transformer are often used to make large changes to the welding current and/or to change the secondary voltage.
For a certain duty cycle, transformer ratings for electric machines are indicated in KVA (kilovolt-amperes). This duty cycle rating, which is also known as a “thermal rating,” describes how much energy the transformer can produce for a certain portion of a given time period, often one minute, without going above its temperature rating.
The maximum current that may be drawn from the transformer is indicated by the RMS short-circuit secondary current standard. The thickness of the materials that may be welded is indicated by this characteristic since heating is a factor in the welding current.
14-Rectifier Transformer for Smelters
A rectifier transformer is a type of transformer that has both semiconductors and rectifiers in the same tank. Voltage control might be included as well. For industrial procedures requiring a sizable direct current (DC) supply, rectifier transformers are utilized. DC locomotion, electrochemical processes, smelter processes, massive variable-speed railway drives, and so on are typical examples.
15-Phase-switching Transformer
A specialized type of transformer called a phase-switching transformer (PST) is commonly used to regulate the active flow of electricity on three-phase electrical distribution networks. By controlling the voltage phase shift difference between both of the system’s two devices, it achieves this.
The theory is based on a series-connected transformer supplied by a shunt transformer that delivers a phase-switching voltage source into the line. The arrangement of the parallel and series transformer units causes the phase switching.
Phase-shifting Transformer IEC 62032-ed2.0-2012 IEC/IEEE 60076-57-1202-2017 IEEE C 57.135-2011
16- HVDC transformers (line transformers and back-to-back transformers).
17- Wind Turbine Transformer
The wind transformers provide a connection between the grid system and the wind turbines. It increases the generator’s small output voltage to a larger level for distribution. Since they are used in wind turbines, transformers are seen as one of the most fragile parts of a wind farm.
Power Transformers for Wind Turbines, IEC 60076-11:2011
18- Solar power Transformers
A solar power transformer was used for solar power applications. Before the DC voltage of photovoltaic systems can be raised to the rated output, it must be changed by a solar panel transformer. It can also be called a solar inverter transformer because it changes DC to AC.
19- Electrostatic Precipitators (ESP) Transformers
Transformers for electrostatic precipitator rectification An electrostatic precipitator is a big piece of industrial emission-control equipment. It is intended to catch and eliminate dust particles from industrial operations’ flue gas streams.
20-Variable frequency drives (VFD) transformers
A VFD transformer is basically a one-to-one isolation transformer that is used with variable frequency drives for fault protection.
21-Transformers for voltage regulators
An autotransformer is one type of transformer that may be used to convert AC voltages in a unique way. Although there is also a physical electrical connection between the primary and secondary windings in the autotransformer, the voltage is also changed magnetically via the steel core.
22-Transformers K factor rating
A K-factor rating tells you how much harmonic power flow a transformer can handle without getting too hot. The K-rating number of the transformer (1, 3, 6, 9, 13, 17, 20, etc.) shows how much harmonic current the transformer can handle.
23- Transformers for control Panel
In the control panel, this type of transformer is used for multi-function protection, such as voltage step-up and step-down for the AC supply of various components.
24- Transformers for isolating power
The isolation transformer is a part that sends power from an AC power source to a piece of equipment or device without connecting the powered item to the AC power source. This is often done for safety concerns or to lessen transients and harmonics.
25- Transformers used for short circuit testing
This transformer is used for testing, specifically on motors, transformers, breakers, and cable short circuits. Additionally, it is used for routine testing of all types of instruments that perform short-circuit tests.
26- Transformers used for high voltage testing
High-voltage test transformers are single-phase transformer solutions that must increase the supply voltage to the required level to perform a dielectric withstand test on liquid or solid insulation.
27-Pulse Transformers
Pulse transformers are a large family of transformers used to connect a load to a control circuit and send digital control signals. They provide a circuit’s electrical isolation while enabling quick control signal transmission without affecting the signal’s form.
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