Distribution transformers play a crucial role in the power grid. They not only provide necessary and reliable electricity for the daily operations of every household and enterprise, but also maintain the safety and stability of the power system. An efficient power system is always inseparable from distribution transformers.
Suppose you are in contact with or trying to understand distribution transformers, or want to use distribution transformers to improve the efficiency and reliability of your power grid. In that case, you can read the following guide carefully. It can expand your understanding of distribution transformers.
1. What Is A Distribution Transformer?
2. What Are The Applications Of Distribution Transformer?
3. How Does Distribution Transformer Work?
4. Why Are Distribution Transformers Important?
5. What Are The Benefits Of Distribution Transformer?
6. What Are The Functions And Uses Of Distribution Transformer?
7. What Are The Types Of Distribution Transformer?
8. What Are The Parts Of Distribution Transformer?
9. What Are The Factors May Affect Transformer Productivity?
10. What Are The Proactive Measures To Prevent Transformer Damage?
11. What Types Of Manufacturer Production Tests May Be Performed On Transformers?
12. What Are The Installation Of Distribution Transformer?
13. What Are The Maintenance of Distribution Transformers?
14. What Are The Transformer Losses?
15. What Is Power Transformer?
16. What Are The Differences Between Distribution Transformers And Power Transformers?
What Is A Distribution Transformer-sourced: scotech-electrical
A distribution transformer is a type of electrical transformer used specifically in power distribution systems. Its primary function is to convert high-voltage electricity from the grid into low-voltage electricity suitable for home and commercial use.
There are many types of this transformer, including single-phase, three-phase, box-type, and pole-type distribution transformers. In addition to being able to step down or step up the voltage from the grid to match the power consumption levels of homes, businesses, and commercial buildings, it also provides a variety of sizes, insulating oils, and efficiencies to meet your project budget and requirements.
Distribution transformers have many uses, including:
Stepping down the voltage
Stepping down voltage-sourced: sstatic
One of the main uses of distribution transformers is to step down the transmission voltage (usually between 69 and 500 kV) to a lower voltage suitable for homes and businesses, while also providing precise power to your electrical equipment.
Power distribution
Power distribution-sourced: sanity
Distribution transformers are a technical means of distributing power from the power grid to different homes, businesses, factories, etc. Therefore, they are often installed at the end of the wire, close to the power consumption point, or on poles and substations.
Voltage regulation
Voltage regulation-sourced: cyberpowersystems
In addition to stepping down and distributing power, distribution transformers can also regulate the voltage drop caused by long-distance power transmission. It can adjust and change the voltage according to different load requirements.
Renewable energy integration
Renewable energy integration-sourced: modelon
Many renewable energy sources, such as solar cells, wind turbines, and other renewable energy sources, can be integrated into the power system through distribution transformers, facilitating the transportation and use of electrical energy.
Industrial uses
Distribution transformers can provide power for different machines and equipment in industrial environments.
The working principle of distribution transformers is derived from electromagnetic induction. Its working principle is:
How Does Distribution Transformer Work-sourced: let'sgrowup
- Coil. The distribution transformer is composed of a primary coil and a secondary coil. The primary coil is connected to the high-voltage electricity from the power grid, while the secondary coil is connected to the low-voltage electricity delivered to homes and businesses.
- Core and windings. The core of the distribution transformer is primarily composed of high-magnetic-permeability silicon steel. It can guide the magnetic field.
- Current induction. When the alternating current passes through the primary winding, the change in current generates a magnetic field. It can reduce the voltage without losing power.
- Voltage conversion. Because there is a turns ratio between the primary winding and the secondary winding. When the secondary winding has fewer turns than the primary winding, the current increases and the voltage decreases. When the secondary winding has more turns than the primary winding, the current decreases and the voltage increases.
Why Are Distribution Transformers Important-sourced: sumanelectricalsonline
Distribution transformers are vital to the power distribution system. They can distribute and transmit electricity to homes and businesses safely and smoothly, and they can also ensure that the distribution system is isolated from the ground, protecting the entire system from electrical faults and maintaining the safety and stability of the entire system.
There are many advantages of distribution transformers, including:
High efficiency
High efficiency-sourced: laars
Distribution transformers have been carefully considered and repeatedly tested from the early stage of research and development, design, optimization, testing, to the later stage of raw material selection, production, and use. Therefore, during use, it can ensure extremely low losses during energy transmission and extremely high efficiency, up to about 97%.
Reliability
Reliability-sourced: automation
After repeated experiments and tests, it can guarantee you high reliability, that is, continuous operation for more than 25 years.
Strong overload capacity
Distribution transformers can cope with peak power consumption and support short-term overloads exceeding the rated capacity.
Protection function
Protection function-sourced: fuda
By setting up protection devices, it can protect distribution transformers from overheating, voltage spikes, short circuits, and other problems.
Low maintenance cost
Distribution transformers are usually equipped with sealed oil tanks and insulating oil, which not only increases the service life of the equipment but also reduces the need for equipment maintenance.
Small footprint
Small footprint-sourced: changanelectric
Compared with power transformers, distribution transformers are usually smaller in size, occupy less space, and can be well integrated into other systems.
More environmentally friendly
More environmentally friendly-sourced: sintef
Distribution transformers generally use non-toxic, biodegradable vegetable oil instead of mineral oil, which is more environmentally friendly.
The main functions of distribution transformers include:
Voltage conversion
Voltage conversion-sourced: allaboutcircuits
Distribution transformers can safely and stably convert high voltage electricity (such as 24.94 kV, 34.5 kV) into low voltage electricity (such as 480V, 220V) suitable for home or commercial use.
Power distribution
Power distribution-sourced: hoptele
Distribution transformers can efficiently and stably supply electricity to residential, commercial and industrial sectors. Therefore, they are often installed in utility poles and substations.
Load management
In order to ensure a stable and uniform supply of electricity, distribution transformers can balance and evenly distribute the power load on the distribution line.
Voltage regulation
Voltage regulation-sourced: geeksforgeeks
Distribution transformers can constantly adjust and stabilize the voltage level on the power grid and power system, protect various electrical and equipment in the circuit, etc.
Grid connection
Grid connection-sourced: gridx
Various renewable energy sources, such as wind power and solar energy, can be smoothly connected and used with the power grid through distribution transformers.
Improve power efficiency
Improve power efficiency-sourced: encrypted
Distribution transformers can flexibly withstand and adjust to overloads and faults in the power system, while reducing energy loss, they can also improve the power efficiency of the system.
There are many types of distribution transformers. Among them, according to the cooling method of the transformer, the types of distribution transformers are:
Dry-type transformer
Dry-type transformer-sourced: LTEC
Unlike oil-immersed transformers, dry-type transformers mainly use air as a cooling and insulation medium, and are often installed in indoor, underground facilities or residential areas with high fire protection requirements. It has a lower overload capacity, but the cost is higher.
Oil-immersed transformer
Oil-immersed transformer-sourced: ppi
Compared with dry-type transformers, oil-immersed transformers usually use oil as an insulator and coolant. This design of transformer has better insulation performance and cooling effect, smaller size, and lower cost. However, during use, it has potential oil leakage and fire hazards, and is not suitable for use in sensitive environments.
According to the installation environment classification, distribution transformers include:
Pole-mounted transformer
Pole-mounted transformer-sourced: ermco-eci
Pole-mounted transformers are named because they are installed on utility poles. In order to prevent being touched, they are installed on high utility poles. And they are not limited by space. In order to prevent being damaged, they are often used in areas with low population density.
Box-type transformer
Box-type transformer-sourced: TSTY
Box-type transformers are usually installed on a concrete base and placed in a tamper-proof metal cabinet. It is suitable for use in urban areas, which is aesthetically pleasing and can be hidden from public view. This type of transformer is usually a three-phase transformer to meet the needs of high loads.
Submersible Transformer
Submersible Transformer-sourced: vantran
Submersible transformers are designed specifically for flood-prone areas. They are rugged and completely sealed to operate underwater and are not affected by moisture or water.
Based on the phase configuration, distribution transformers include:
Single-Phase Transformer
Single-Phase Transformer-sourced: elprocus
Single-phase transformers are simpler in design but more cost-effective. They can meet the needs of residential and commercial environments with relatively low power demand and a wide distribution range of power, such as pole-mounted transformers.
Three-Phase Transformer
Three-Phase Transformer-sourced: belfuse
Three-phase transformers can be used in more complex industrial environments. It can distribute power more smoothly and efficiently. It can balance and handle high power demands while continuously supplying power.
The key parts of distribution transformers include:
Windings
Windings-sourced: maddox
Distribution transformers include primary and secondary windings. These windings are usually made of copper or aluminum. Copper is more conductive and efficient, but more expensive than aluminum. These windings form the conductive coils of the transformer. They are tightly wound around the core to promote the induction process of the transformer.
Core
Core-sourced: corefficientsrl
The core of the transformer is usually made of multiple layers of silicon steel sheets. It can reduce eddy currents and minimize hysteresis losses.
Insulators
Insulators-sourced: cnruisen
Different distribution transformers use different insulators. Transformer insulator materials include oil-impregnated paper and resin. These two materials have good dielectric properties and durability, and can withstand thermal, electrical, and mechanical stresses.
Tap changer
Tap changer-sourced: maddox
The tap changer can adjust the voltage ratio between the first winding and the second winding to adjust the output voltage to adapt to changes in load or input voltage. The tap changer is essential to maintain the voltage level of the power grid system, and mechanical wear and electrical corrosion during use will cause losses to the tap changer, so the tap changer switches need to be continuously maintained in the later stages.
Conservator tank
Conservator tank-sourced: elprocus
The conservator tank provides excellent physical protection and sealing for the internal components of the transformer, thereby controlling the internal pressure. It is usually grounded to prevent electrical hazards and painted to resist environmental effects such as rust and UV degradation.
Bushing
The bushing of the transformer is usually made of ceramic or composite materials to control the distribution of electric fields. It can withstand high voltages and complex external environments. Because bushing failure can cause catastrophic damage, you need to test and maintain it according to strict standards during later use.
Breathing device
The breathing device can maintain the moisture balance in the transformer oil to maintain good insulation. As the transformer heats and cools, the breathing device can keep the air inside dry.
Oil conservator
The oil conservator protects the stability of the oil level in the main oil tank, thereby maintaining the best insulation performance of the transformer. Nowadays, bladder oil conservators are generally used, which can completely isolate the outside air.
Heat sink or radiator
Heat sink or radiator-sourced: cncstamping
The heat sink increases the surface area of the oil tank, thereby enhancing the heat dissipation effect of the transformer.
The performance of distribution transformers can be affected by various conditions and factors, and you should try to avoid:
Overload
Overload-sourced: zx-ele
Continuous overload will put excessive stress on the distribution transformer, which will shorten the life of the equipment.
Environmental factors
Excessive environmental factors, such as strong winds, fires or heavy rain, will reduce the performance and efficiency of the transformer.
Lack of maintenance
Lack of maintenance-sourced: seton
Neglected maintenance is the main factor leading to transformer failure. You need to maintain the transformer regularly.
There are many ways to prevent transformer damage, including:
Proper installation
Proper installation-sourced: daelim-electric
After obtaining the transformer, you need to install it strictly according to the instructions. If necessary, you need to consult a professional engineer.
Install protective devices
Install protective devices-sourced: circuitdigest
In addition to the distribution transformer, you need to install protective devices, such as surge protectors or circuit breakers. This device can prevent the transformer from electrical overload.
Regular maintenance
Regular maintenance-sourced: hi-techcarcare
Regularly maintain and inspect the distribution transformer, and sample and test the oil.
Regular monitoring and replacement
Each distribution transformer has a specific lifespan. You need to monitor and replace it regularly to ensure safe and reliable operation.
Distribution transformer testing standards are routinely tested as per the IEEE Standards Committee. The tests are routine and design tests. Routine tests are tests that are performed on all transformer units. Design tests are tests that are performed only on new designs or prototypes.
Routine tests include:
Ratio, Polarity and Phase Relationship Tests
Ratio, Polarity and Phase Relationship Tests-sourced: electrical4u
Ratio, polarity, and phase relationship testing is extremely important to verify that the transformer has the correct high and low voltage turns ratio. It verifies that the unit has open circuits, short circuits (turn to turn), and correct polarity and phase relationships.
Resistance Tests
Resistance Tests-sourced: carelabz
By performing resistance tests, you can verify that the coil resistance and wire diameter are as expected compared to the design values, thereby obtaining the correct resistance value for winding losses.
Insulation Power Factor Tests
Insulation Power Factor Tests-sourced: vertiv
The insulation power factor test determines the ratio of the power dissipated in the insulation to the product of the effective voltage and current.
Quality Control (QC) Pulse Tests
It verifies the insulation integrity and BIL rating of the unit.
Core Loss (No-Load Loss) and Percent Excitation Current Test
Core Loss (No-Load Loss) and Percent Excitation Current Test-sourced: powersystemsdesign
The purpose of this test is to check the accuracy of the design calculations, workmanship, and materials. Actual measurements are collected for customer use and total ownership calculations.
Induction Potential (OX) Test
Induction Potential (OX) Test-sourced: mdpi
All units are required to undergo the Induction Potential (OX) test. It checks both turn-to-turn and layer-to-layer insulation. This test is performed prior to the winding loss and impedance tests.
Optional Tests Include:
IEEE Pulse Test (Damped Wave, Twice Chopped Wave, Full Wave)
IEEE Pulse Test (Damped Wave, Twice Chopped Wave, Full Wave)-sourced: googleusercontent
The IEEE Pulse Test (Damped Wave, Twice Chopped Wave, Full Wave) is designed to simulate the severe surges that a transformer may encounter throughout its service life.
Sound Level Test
The sound level test is designed to detect the amount of audible noise that a transformer produces during use. Sound levels are measured at regular intervals around the unit, and the average value is read.
Thermal Temperature Test
The thermal temperature test is primarily designed to evaluate the thermal characteristics of the transformer, specifically its ability to remain cool during operation.
The installation steps of distribution transformers need to be strictly followed. These include:
Site selection
Site selection-sourced: reinhausen
Before installing the transformer, you need to select an environment and location that is suitable for the transformer. The distribution transformer should be installed as close to the load as possible to reduce energy loss in the distribution line and facilitate maintenance.
Foundation and installation
Distribution transformers can be installed on poles or concrete pads. Installing on poles can reduce the risk of tampering. Installing on the base can maintain the stability of the transformer.
Connection and commissioning
Connection and commissioning-sourced: zenithar
After installing the distribution transformers, you need to ensure that they are properly grounded to prevent electrical hazards. Commissioning and testing can check whether the phase and voltage output are correct and whether they comply with safety regulations.
Safety and compliance
During use, you need to comply with local electrical safety regulations and standards. These include: maintaining an appropriate distance from the building and ensuring that protective devices such as circuit indicators and surge protectors are installed.
Maintenance of distribution transformers is also very important. You can implement it by following the steps below:
Regular inspections
Regular inspections-sourced: reinhausen
You can assign engineers to regularly inspect the equipment for wear, oil leakage (oil-immersed transformers), and external components such as bushings and casings. Clean and remove dirt and debris from the surface of the equipment regularly.
Oil management (oil-immersed transformers)
Oil management (oil-immersed transformers)-sourced: researchgate
If you use oil-immersed transformers, you need to regularly test the dielectric strength and contamination of the transformer oil. Regularly sample and test the oil to ensure the insulation performance and heat transfer efficiency of the equipment.
Thermal imaging
Thermal imaging-sourced: researchgate
Use thermal imaging to detect and identify overheated components inside the transformer, check for internal faults, overloads, or insulation failures.
Electrical testing
Electrical testing-sourced: elecsafety
Electrical testing includes insulation resistance, turns ratio testing, and power factor testing. It can ensure that the internal components of the transformer are operating normally.
Load monitoring and analysis
Under actual operating conditions, you can perform load monitoring and analysis to test the actual operating performance and efficiency of the equipment.
Preventive maintenance
Based on the actual operation of the equipment, you can formulate a preventive maintenance plan to facilitate the handling of equipment failures.
Transformer losses are caused by the alternating magnetic field in the core. They occur during the entire power-on process. These losses include:
No-load losses
No-load losses-sourced: electrical-engineering-portal
No-load losses are also called core losses or iron losses. They are mainly caused by losses in the core steel, eddy currents, hysteresis, stray eddy currents, and dielectric losses.
Load losses
Load losses-sourced: polytechnichub
Load losses are also called copper losses. They are mainly caused by coil losses. The primary and secondary winding resistances of the transformer generate heat losses, which cause load losses.
What Is Power Transformer-sourced: iqsdirectory
Unlike distribution transformers, power transformers are transformers that are located specifically within substations. They are rated at more than 1000 kVA and are typically used for large industrial or commercial loads. They are often installed close to the load.
Power transformers and distribution transformers are both transformers, but they differ in their application scope, scenarios, and other conveniences. Their differences include:
|
Distribution transformer
|
Power transformer
|
|
| Rated capacity | Lower; | Usually higher, more than 3150kVA; |
| Rated voltage range | Range from 11kV, 6.6kV, 3.3kV, 440V to 230V; | Range from 400kV, 200kV, 66kV to 33kV; |
| Size | Smaller size, lower current; | Larger size, higher current; |
| Installation location | Mainly installed in distribution stations; | Power stations and transmission substations; |
| Purpose | Deliver electricity to industry or households; | Deliver electricity to large industries or commerce; |
| Insulation level | Low; | High; |
| Iron loss and copper loss | Without any core parts, the iron loss is lower than that of power transformers; | Eddy current loss in steel sheets and hysteresis loss in core materials will lose energy in the form of heat; |
| Efficiency | Higher efficiency than power transformers, the efficiency can reach about 80%-90%. | The efficiency of power transformers is usually lower than that of distribution transformers; the efficiency can reach about 75%. |
Distribution transformers play a crucial role in all power distribution systems. In order to achieve a safe and efficient power supply to homes and businesses, more distribution transformers are being developed and manufactured. In the future, more manufacturers and companies will continue to work hard to improve the high-voltage power adjustment level of distribution transformers, maintain the best performance of equipment, and extend the service life of equipment. If you are worried about choosing a suitable distribution transformer, please contact us immediately to get the best selection solution.
