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Switchgear system with a voltage from 3kv to 36kv is classified as medium voltage switchgear or MV switchgear. There are types of Switchgear such as metal-enclosed indoor type switchgear, metal-enclosed outdoor type switchgear, outdoor type switchgear without metal enclosure, etc. The interruption medium of this switchgear may be insulating oil, SF ₆ gas, or vacuum. The power network is mainly required to interrupt current during faulty conditions irrespective of what type of CB is used in the MV switchgear system.
The functions of Medium voltage switchgear are given as:

All the above-mentioned functions must be implemented with a high degree of safety and reliability.

design mainly focuses on that all circuit breakers should be capable of interrupting short circuit current with a high degree of reliability and safety. The number of faulty tripping occurred during the total lifespan of a circuit breaker mainly relies on the location of the system, the quality of the system, and environmental conditions. In case of a much higher number of tripping, a vacuum circuit breaker is the best choice as it may not require any maintenance up to 100 faulty tripping with a short circuit current up to 25 KA. Whereas, other circuit breakers need to be maintained after 15 to 20 faulty tripping with the same short circuit current of CB. The substations reunited in rural areas are generally of an outdoor type, and most of them are the unattended type. Hence for this type of application maintenance-free outdoor type, medium voltage switchgear is most suitable. Porcelain clad vacuum circuit breaker meets this demand against the conventional indoor kiosks.

The function of the capacitor bank in a medium voltage power system is to improve the power factor of the system. Unloaded overhead lines and Unloaded cables have also capacitive charging current and should be disconnected from the system safely without re-ionization. overvoltage is caused by Re-ionization in the contact gap in the system. The vacuum circuit breaker meets the requirement.
While switching on a capacitor bank, a high rate of rising of making current will flow through the contacts. A circuit breaker with liquid quenching medium and tulip contacts may suffer from contact pin retardation. Vacuum medium voltage switchgear is the most perfect choice for this purpose, as vacuum circuit breaker has low electric arcing during short pre arcing time.

Older VCB had a current chopping level of 20 A when these breakers were used to switch , special surge protection devices were required. Modern has a very low chopping current which is about 2 - 4A. Hence modern vacuum medium voltage switchgear is very much suitable for switching an unloaded transformer. As the modern VCB chops the current at a very low level, there is no need for additional surge protection devices. Hence VCB is suitable for very low inductive load switching. But when the inductive current in the system is low but not very low VCB is the best choice.

is applied for a single-phase railway track system. The main function of the circuit breaker associated with the railway traction system is to interrupt the short circuits, on the overhead catenary system which occurs frequently and it is transient. Hence, a circuit breaker used for this purpose should have, short braking time for small contact gap, short arcing time, quick breaking, and VCB is the best possible solution. Arcing energy is much higher in the single-phase CB than 3 phase CB. It is still much lower in a vacuum circuit breaker than that in a conventional circuit breaker. The number of short circuits that occur in the overhead catenary system is much higher than those occurring in the electrical transmission system. Medium voltage switchgear with a vacuum circuit breaker is most suitable for traction application. We can conclude that, in the medium-voltage system where the tripping rate is very high, MV Vacuum Switchgear is the most suitable solution.

An electric arc furnace is required to be switched OFF and ON frequently. The current to be switched may be from 0 to 8 times the rated current of the furnace. An electric arc furnace is to be switched ON and OFF at its normal rated current up to 2000A, around 100 times per day. A normal, , air circuit breaker, and the oil circuit breaker is not at all economical for this frequent operation. A standard vacuum circuit breaker is the most suitable alternative for this frequent high current circuit breaker operation.

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Switchgear system with a voltage from 3kv to 36kv is classified as medium voltage switchgear or MV switchgear. There are types of Switchgear such as metal-enclosed indoor type switchgear, metal-enclosed outdoor type switchgear, outdoor type switchgear without metal enclosure, etc. The interruption medium of this switchgear may be insulating oil, SF 6 gas, or vacuum.

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What is pole mounted transformer? pros and cons of pole mounted transformer? Where to buy pole mounted transformer?

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RMU (Ring Main Unit) cabinet or medium voltage cabinet is integrated electrical equipment to connect, measure, and integrate fixed type breaker with transformer protection function.

RMU cabinets are small in size, highly reliable, safe, easy to maintain, easy to replace, and expand. Depending on requirements, the RMU is available in different voltages suitable for both indoor and outdoor installations.

2. Structure of a Ring Main Unit (RMU)

The RMU cabinet is connected by output and input cable compartments by isolating breakers and cables out to transformers using load breakers and protective fuses.

In general, the switch element (including load breaker, cutter machine, and ground knife, busbar, and terminals) is placed in an SF6 gas tank made of a substance that is particularly resistant to the environment, such as dirt, oil grease, not rust.

RMU cabinets are divided and connected by separate compartments, with RMU standards with two compartments, four compartments, six compartments, depending on customer requirements with functions of them.

In the past, most protection schemes for medium / low voltage transformers in distribution grids used fuse combined with a cutter knife commonly. It's a simple and cost-effective solution. On the other hand, circuit breakers in the past were often expensive and used in high/medium voltage (HV / MV) stations instead of medium / low voltage (MV / LV) stations.

Recently, mid-voltage cabinet manufacturers such as Schneider Electric design a compact RMU cabinet breaker that incorporates SF6 gas insulators, self-powered relays, and optimized current transformers at a total cost of ownership the equivalent of a mid-voltage fuse-cutter solution.

One of the reasons electricity contractors and private customers choose the circuit breaker solution is improving service quality while optimizing the investment costs. The circuit breaker with self-powered relays is more comfortable to install than the medium voltage fuse and suitable for combined upstream and downstream protection.

3. Purpose of using RMU

The essential functions of the switchgear are:

Circuit control: It controls the circuit to switch functions.

Isolation: It isolates the faulty equipment from the rest of the circuit

Protection: It protects the circuit from ground-fault current, short-circuits current fault, and overload.

Compared with medium voltage fuses, the circuit breaker combined with relays will enhance the ability to protect selectively; Avoid incorrect operation of the transformer's surge current; Detecting phase-to-phase fault currents and small earth intensity.

RMU electrical cabinets are used with many different applications in the secondary circuit distribution system, with the function of input switching for transformer stations, integrated transformer stations, etc., in many fields of business.
A video introduction of RMU cabinets:
4. Advantages of Ring Main Unit

RMU cabinets are an innovative solution that makes it easy to manage the many challenges of power distribution. The RMU is an all-in-one solution cause it is safe switchgear, easy to install, and free to maintain, helping utilities improve network reliability and uptime and reduce operating costs onions.

Reduce maintenance and spare parts: Today's relays require virtually no maintenance, as they incorporate self-test features. Furthermore, the protective circuit can be easily checked during commissioning with simple test equipment.

Better tolerance to harsh environments: The circuit breaker in the RMU cabinet is located inside the chamber filled with SF6 gas, so it is not affected by environmental conditions.

Improved protection against magnetizing overload currents, phase-to-phase fault currents, and ground contact current with low intensity

RMU help to better coordinate protection with other medium voltage and low voltage protective equipment.

Feature-rich compact design: Ring main unit is SF6 Insulated Compact Switch equipped with SF6 Switch breaker and vacuum circuit breaker. Its compact design does not require too much space to install and operate.

Saving time and money: The RMU is switchgear complete and easy to install, saves installation and operation time. Irrespective of the climate and withstand the environmental conditions, these units' operation and maintenance costs are also low.

Safety and Performance: RMU's state-of-the-art compact design and latest technologies ensure complete safety, connectivity, reliability, and efficiency.

Intelligence capabilities: Equipped with smart electronics and communication capabilities, RMU easily integrates with the Distribution Management System and builds Smart Grid solutions.

The lifetime of the device is over 20 years.

Stable operation in any extreme climatic conditions -2500C ÷ + 4000C

5. Types of Ring Main Unit

a. Based on the structure

b. Based on the kind of arc stamping in the gas chamber, insulation properties

Electrical insulation cabinet in an air environment

Electrical insulation cabinet in a vacuum environment

Electrical insulation cabinet in SF6 gas environment

c. Based on the voltage level

6. Genuine distributors of RMU

Currently, RMU cabinets used for switching stations are mainly imported from abroad from several major companies such as ABB medium voltage cabinets (Sweden), (Germany), (France), etc. The Schneider' RMU cabinets are trusted by customers to use more popularly because of its advantages.

MBT honor to be Schneider products' genuine distributor, especially RMU electrical cabinets, Recloser automatic switchgear. Customers who have demand for RMU cabinet products, please contact hotline +84913.006.538 or email: [email protected] for advice and a free quotation.

MBT is committed to providing genuine products with the most preferential prices and the best customer care services.
MBT- "Quality Nurtures Reliability"

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RMU (Ring Main Unit) cabinet or medium voltage cabinet is integrated electrical equipment to connect, measure, and integrate fixed type breaker with transformer protection function. RMU cabinets are small in size, highly reliable, safe, easy to maintain, easy to replace, and expand.

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Dry-type transformer construction is much different from the liquid transformer. Look at the picture below to know all the dry-type transformer parts.

Dry-type transformer construction

There are some typical parts of dry-type transformer:

Dry Type Transformer Taps - Dry type transformer construction

The transformer can be equipped with voltage taps in the high-voltage winding. Normally, two taps above and two below rated voltage are provided, giving a total induced voltage range of 10% (ANSI/IEEE, 1981 [R1989]; ANSI/IEEE C57.12.52-1981 [R1998] ).

Cooling Classes for Dry-Type Transformers - Dry type transformer construction

Cooling class designations for the US and Europe are shown in Table 2.5.1. The cooling classes for dry type transformers are as follows (IEEE, 100, 1996; ANSI/IEEE, C57.94-1982 (R-1987)):

Ventilation - Ambient air can circulate, cooling the transformer core and windings

No ventilation - No intentional circulation of outside air through the transformer

Hermetic - Self-cooling transformer with sealed enclosure

Self-Cooling - Cooling by natural air circulation

Air cooler - Forced recirculation air cooling

Self-Cooling / Forced Cooling - Rated natural circulating cooling and forced circulation cooling by wind.

Winding Insulation System

It is common practice to use resins or varnishes to seal or coat dry-type transformer windings to protect against adverse environmental conditions that can cause transformer winding deterioration. Insulating means for primary and secondary windings are classified as follows:

Molded Coil - The coil is reinforced or placed in a mold and molded in plastic under vacuum pressure. Lower sound levels are achieved when the coil is wrapped in solid insulation. Fill the coil with resin under vacuum to eliminate gaps that can cause halos. With solid insulation, the coil has outstanding short-circuit and mechanical strength, and is impervious to moisture and contaminants.

Vacuum Pressure Enclosure - The coil is embedded in the plastic under vacuum pressure. Wrapping the coils in plastic under vacuum conditions eliminates gaps that can cause halos. The coil has excellent mechanical and short-circuit strength and protects against moisture and contaminants.

Vacuum Impregnated - Coil is impregnated with varnish under vacuum pressure. An impregnated coil protects against moisture and contaminants.

Coated - The coil is dipped with varnish or turpentine. A coated coil provides multiple layers of protection against moisture and contaminants for application in moderate environments.

Below are two pictures of the dry-type transformer assembly.

Accessory

Coil temperature indicators can be equipped with contacts to provide indication and/or warning of coil temperature approaching or exceeding maximum operating limits. For sealed dry type transformers, gas pressure switches may be equipped with contacts to provide indication and/or warning of gas pressure deviation from the recommended operating pressure range.

Surge Protection

For transformers exposed to lightning or other surge voltages, the protective surge arrester shall be compatible with the transformer's basic lightning impulse insulation level, BIL.

The length of the conductor connecting the bushings of the transformer to the arrester - and from the arrester earth to the neutral - shall be the minimum length to eliminate induced voltages in the ground wire and earth current ( ANSI). -IEEE, C62.2-1987 [R1994]).

A lower BIL level may be applied when the surge arrester provides adequate protection. At 25 kV and above, a higher BIL level may be required because of overvoltage contact or for a higher margin of protection (ANSI/IEEE, C57.12.01-1989 [R1998]).

Access for more information:

Cast Resin Transformer

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Dry-type transformer construction- MBT Electric

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Dry-type transformer construction is much different from the liquid transformer. Look at the picture below to know all the dry-type transformer parts. Dry-type transformer construction There are some typical parts of dry-type transformer: The transformer can be equipped with voltage taps in the high-voltage winding.

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With the development of the electricity industry and some other sectors, the transformer is vital equipment. They use it widely to solve electricity matters. To know more about this product, let us show you its meaning, structure, and types.

Purpose of using transformer: The transformer converses alternating voltage. It can raise or reduce initial voltage according to its turns. Today, the electricity transformer device has a shorter name, which is the transformer. The transformer is an electromagnetic device. According to the electromagnetic induction principle , it works to converse an alternating current in this voltage to another voltage with a constant frequency.

Transformer definition : The transformer is an electric device using electromagnetic induction to pass, transfer energy, or alternating current signals between electronic circuits with a particular principle. Some people have a wrong thought with the transformer function. Practically, the transformer has the task of transferring or distributing energy, not changing them.

To know more about , you should understand about its components.The transformer has four parts: The Input Connection, the Output Connection, the Windings or Coils, and the Core.
Types of transformer
The oil-immersed transformer has 2 types: Sealed type and open type.

Sealed type transformers don't have a sub oil tank when open type transformer is vice versa.

Dry-type transformer definition : It is an electric device that is entirely stationary, and when operating, it needs less maintenance to prevent dangers. Different from oil-immersed transformers, dry-type transformer just applies high-temperature insulation systems that are incredibly safe. Not need fire-resistant vaults and not realize toxic gasses, the device gives a secure and consistent electric power to emit harmful gasses otherwise catch basins. Because of these safety factors, the dry-type transformer is installed in many places, such as hospitals, schools, buildings, and chemical factories.

Cast Resin Dry Type transformer definition: Used mainly in areas with high humidity, CRT has primary and secondary windings coated by epoxy resin. CRT helps to prevent the ingress of moisture from affecting the quality and longevity of the windings. CRT keeps running without being interrupted by weather conditions. Due to this property, this type of transformer is not hygroscopic. CRT has a range in capacity from 25 KVA to 12,500 KVA, with insulation class F (90oC Temp. Rise).

Vacuum Pressure Impregnated transformer definition This type of transformer also uses a non-combustible material (usually H-grade Polyester) as the coil's insulation and to avoid contamination. Metal foil is arranged in continuous layers to form a winding core. For high voltage machines, the winding is made in the form of a disc and connected in series or parallel according to the power level corresponding to the voltage level. The primary, secondary windings and the core are securely fastened in a vacuum shielding box. This box prevents the transformers from being affected by moisture. This transformer has capacities of 5KVA to 30MVA with insulation classes F (155oC) and H (180oC). With protection up to IP56.

4. COMPANY MANUFACTURE TRANSFORMER IN VIETNAM

Website: http://vietnamtransformer.com/

Address: Song Cung Industrial zone, Dong Thap Commune, Dan Phuong District, Hanoi, Vietnam.

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With the development of the electricity industry and some other sectors, the transformer is vital equipment. They use it widely to solve electricity matters. To know more about this product, let us show you its meaning, structure, and types. Purpose of using transformer: The transformer converses alternating voltage.

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Types of transformers. The transformers are classified based on voltage levels, Core medium used, winding arrangements, use and installation place, etc.

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An electrical transformer is an essential device in the distribution and transmission system of electricity in the national grid electricity system. Along with the development of technology, the transformer manufacturing industry has also overgrown in recent years. Amorphous transformers were born with many outstanding features that outperformed those of the same type: saving operating costs, reducing CO2 emissions into the environment, increasing product life cycle, ...
1. What is an Amorphous Core Transformer?

An amorphous core transformer is a core transformer made of amorphous steel. The most significant benefit of an amorphous transformer is that the amorphous steel has lower hysteresis loss. In other words, transformers made of this amorphous steel waste less energy (in the form of heat) during the magnetization and demagnetization of the core.

2. What are Amorphous Metals?

The molten alloys are rapidly cooled at a rate above 1 million ° C per second to produce amorphous metal. Amorphous metal is a metal that has no crystalline structure, which imparts different properties in different directions. In other words, this metal has a random atomic structure, which makes it extremely useful in transformer applications. It has both high permeability and excellent soft magnetic properties.

Amorphous metals are used in transformers such as pole transformers and industrial transformers with a predominantly iron composition. Compared with conventional materials such as silicon steel, amorphous metal materials have small no-load losses (iron losses), equal to 1/5 of silicon steel. Therefore, they make a significant contribution to energy conservation.

3. Structure of the Amorphous transformer

The amorphous transformer structure is the same as an ordinary transformer's general structure. The main difference is that the core of a transformer is made from amorphous metal.

The structure of the amorphous core specifies the windings of rectangular construction. Once the design has been established, the magnetic circuit's rectangular profile is resistant to short-circuit stresses.
Amorphous transformer magnetic core
The magnetic circuit consists of pre-assembled single-phase coil sheets, incubated at about 3500 ° C. Once the magnetic circuit has been installed, it will stiffen and act as mechanical support on which all the transformer elements rest.

4. Processing cores from amorphous transformers

Because the amorphous material is so thin, to avoid the appearance of core debris by applying the following procedure:

Epoxy coating is covered on both sides of the assembly core except in the coil open position. As a result, the individual core layers become a solid block and stay in place. Additionally, the core assembly is wrapped with CRGO panels to provide mechanical strength.

FRP (composite resin) insulation is provided between the low-voltage coil and the core to reduce force's effect on the core assembly during the transformer operation. The forces generated during transformer operation are absorbed by FRP, thereby reducing the force on the core.

For transformers with a rating above 250kVA, the silver paper should be used for the LV (low voltage) windings. This reduces the axial force and increases the short-circuit resistance of the transformer. We use epoxy diamond dot paper (EDD) as interlayer insulation for LV & HV (low pressure and high voltage) coils.

EDD paper is created using a heat-resistant plastic in the form of square dots on both sides of the kraft paper. The pattern of the plastic dots ensures that there is enough space between them for oil impregnation. The coils produced by this process are dried in an oven in which the plastic melts and hardens. Through this process, the layers are glued together, and the complete coil becomes a solid block.

In Amorphous transformers, the presence of steel core debris is inevitable. During the manufacturing process, the core overlap area is located at the bottom, and the compartment layout is provided for the core. As a result, any core debris that has formed is collected in the workpiece containment system and does not float in the oil.

5. The amorphous transformer manufacturing costs

An amorphous core transformer's total cost is approximately 20% to 30% higher than that of a CRGO Core Transformer.
Why does the amorphous core have a rectangular cross-section?
Several attempts have been made to reduce the cost of CRGO core transformers by prioritizing the circular cross-section of the CRGO core instead of the rectangular cross-section.

For a circular cross-section of the core, the average length of the rotation is reduced, so the mass of copper used in the coil decreases; thus, the transformer's cost is reduced by reducing winding costs.

Manufacturers distributing amorphous transformer cores are very limited for two reasons:

The high cost of materials

Amorphous transformer cores are very brittle and fragile

Because of its limited brittleness, in amorphous core transformers, manufacturers use a square or rectangular cross-section of the core.

6. The benefits of amorphous metal cores

An amorphous metal core transformer's great benefit is that the amorphous steel core has a lower hysteresis loss. Since there is no atomic arrangement law, the small energy loss (delay) when the induced current flows through the iron core.

Non-crystalline structure and random arrangement of atoms give low magnetic fields and high resistivity. Due to the magnetic field, low delay, and eddy currents with high resistivity, losses are minimal. As the core loss of metal alloy amorphous reduced by 42% and the magnetization current is 53%.

Besides, eddy current losses are reduced because of a thickness of approximately 0.03 mm, about 1/10 of silicon steel. The no-load loss rating is 1/4 to 1/3 of transformers that use traditional silicon steel for the core. By the way, the temperature in this amorphous steel core is low, which will significantly reduce the amount of air CO2 released into the environment.

Two types of energy losses are inherent in a distribution transformer's operation: Load losses (copper losses) vary depending on the transformer load, and no-load losses (iron losses) occur out in a magnetic field. When this is replaced with amorphous metal, the transformer's core is reduced by up to 75%.

a. Advantages of amorphous transformer

In the past, awareness of global warming and gas emissions was not as concerned as today, and the concept of "Energy Efficiency" was not a priority in transformer design. The Amorphous Core Transformer is an alternative to conventional transformers. It is mainly used to reduce no-load losses compared to conventional core transformers, thereby significantly saving energy.

Reducing CO2 and SO2 waste

The magnetization flow is reduced

Decreased core temperature rise

Save accumulated energy costs

The lifetime of the transformer is increased (25 - 30 years)

Provides the key to improving utility economics and increasing energy efficiency efforts

b. Disadvantages of amorphous machines

Besides these outstanding advantages, amorphous transformers also have the following disadvantages:

The material is fragile 0.03 mm, so it isn't easy to handle

Amorphous metal is brittle, so be careful during assembly, not too strong.

Specialized lines of machinery and technological equipment are needed to manufacture and assemble the core

Only a few enterprises are capable of manufacturing this type of transformer

The manufacturing process for the amorphous steel core:

8. Amorphous Transformer Quotes

MBT is a brand of transformer products that have a high reputation in the market. With the strength of experience and technological lines in manufacturing, a good team of engineers, skilled technical workers, and abundant customer partners in many areas, so we are always leading about quality of service and price.

We design, manufacture, and supply all kinds of electrical transformers with a dedicated project manager and a 24-month guarantee from dispatch.

With the business motto: "A satisfied customer is the best business strategy of all," and over 11 years of experience in transformer design and manufacture. We, MBT, are confident of being the best Transformer manufacturer in Vietnam.

Contact immediately +84913 006 538 or email: [email protected] for a free consultation and support and receive the most preferential quotation.

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Amorphous transformer | MBT Electrical Equipment JSC

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An electrical transformer is an essential device in the distribution and transmission system of electricity in the national grid electricity system. Along with the development of technology, the transformer manufacturing industry has also overgrown in recent years.

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An electrical transformer is an essential device in the distribution and transmission system of electricity in the national grid electricity system. Along with the development of technology, the transformer manufacturing industry has also overgrown in recent years. Amorphous transformers were born with many outstanding features that outperformed those of the same type: saving operating costs, reducing CO2 emissions into the environment, increasing product life cycle, ...
1. What is an Amorphous Core Transformer?

An amorphous core transformer is a core transformer made of amorphous steel. The most significant benefit of an amorphous transformer is that the amorphous steel has lower hysteresis loss. In other words, transformers made of this amorphous steel waste less energy (in the form of heat) during the magnetization and demagnetization of the core.

2. What are Amorphous Metals?

The molten alloys are rapidly cooled at a rate above 1 million ° C per second to produce amorphous metal. Amorphous metal is a metal that has no crystalline structure, which imparts different properties in different directions. In other words, this metal has a random atomic structure, which makes it extremely useful in transformer applications. It has both high permeability and excellent soft magnetic properties.

Amorphous metals are used in transformers such as pole transformers and industrial transformers with a predominantly iron composition. Compared with conventional materials such as silicon steel, amorphous metal materials have small no-load losses (iron losses), equal to 1/5 of silicon steel. Therefore, they make a significant contribution to energy conservation.

3. Structure of the Amorphous transformer

The amorphous transformer structure is the same as an ordinary transformer's general structure. The main difference is that the core of a transformer is made from amorphous metal.

The structure of the amorphous core specifies the windings of rectangular construction. Once the design has been established, the magnetic circuit's rectangular profile is resistant to short-circuit stresses.
Amorphous transformer magnetic core
The magnetic circuit consists of pre-assembled single-phase coil sheets, incubated at about 3500 ° C. Once the magnetic circuit has been installed, it will stiffen and act as mechanical support on which all the transformer elements rest.

4. Processing cores from amorphous transformers

Because the amorphous material is so thin, to avoid the appearance of core debris by applying the following procedure:

Epoxy coating is covered on both sides of the assembly core except in the coil open position. As a result, the individual core layers become a solid block and stay in place. Additionally, the core assembly is wrapped with CRGO panels to provide mechanical strength.

FRP (composite resin) insulation is provided between the low-voltage coil and the core to reduce force's effect on the core assembly during the transformer operation. The forces generated during transformer operation are absorbed by FRP, thereby reducing the force on the core.

For transformers with a rating above 250kVA, the silver paper should be used for the LV (low voltage) windings. This reduces the axial force and increases the short-circuit resistance of the transformer. We use epoxy diamond dot paper (EDD) as interlayer insulation for LV & HV (low pressure and high voltage) coils.

EDD paper is created using a heat-resistant plastic in the form of square dots on both sides of the kraft paper. The pattern of the plastic dots ensures that there is enough space between them for oil impregnation. The coils produced by this process are dried in an oven in which the plastic melts and hardens. Through this process, the layers are glued together, and the complete coil becomes a solid block.

In Amorphous transformers, the presence of steel core debris is inevitable. During the manufacturing process, the core overlap area is located at the bottom, and the compartment layout is provided for the core. As a result, any core debris that has formed is collected in the workpiece containment system and does not float in the oil.

5. The amorphous transformer manufacturing costs

An amorphous core transformer's total cost is approximately 20% to 30% higher than that of a CRGO Core Transformer.
Why does the amorphous core have a rectangular cross-section?
Several attempts have been made to reduce the cost of CRGO core transformers by prioritizing the circular cross-section of the CRGO core instead of the rectangular cross-section.

For a circular cross-section of the core, the average length of the rotation is reduced, so the mass of copper used in the coil decreases; thus, the transformer's cost is reduced by reducing winding costs.

Manufacturers distributing amorphous transformer cores are very limited for two reasons:

The high cost of materials

Amorphous transformer cores are very brittle and fragile

Because of its limited brittleness, in amorphous core transformers, manufacturers use a square or rectangular cross-section of the core.

6. The benefits of amorphous metal cores

An amorphous metal core transformer's great benefit is that the amorphous steel core has a lower hysteresis loss. Since there is no atomic arrangement law, the small energy loss (delay) when the induced current flows through the iron core.

Non-crystalline structure and random arrangement of atoms give low magnetic fields and high resistivity. Due to the magnetic field, low delay, and eddy currents with high resistivity, losses are minimal. As the core loss of metal alloy amorphous reduced by 42% and the magnetization current is 53%.

Besides, eddy current losses are reduced because of a thickness of approximately 0.03 mm, about 1/10 of silicon steel. The no-load loss rating is 1/4 to 1/3 of transformers that use traditional silicon steel for the core. By the way, the temperature in this amorphous steel core is low, which will significantly reduce the amount of air CO2 released into the environment.

Two types of energy losses are inherent in a distribution transformer's operation: Load losses (copper losses) vary depending on the transformer load, and no-load losses (iron losses) occur out in a magnetic field. When this is replaced with amorphous metal, the transformer's core is reduced by up to 75%.

a. Advantages of amorphous transformer

In the past, awareness of global warming and gas emissions was not as concerned as today, and the concept of "Energy Efficiency" was not a priority in transformer design. The Amorphous Core Transformer is an alternative to conventional transformers. It is mainly used to reduce no-load losses compared to conventional core transformers, thereby significantly saving energy.

Reducing CO2 and SO2 waste

The magnetization flow is reduced

Decreased core temperature rise

Save accumulated energy costs

The lifetime of the transformer is increased (25 - 30 years)

Provides the key to improving utility economics and increasing energy efficiency efforts

b. Disadvantages of amorphous machines

Besides these outstanding advantages, amorphous transformers also have the following disadvantages:

The material is fragile 0.03 mm, so it isn't easy to handle

Amorphous metal is brittle, so be careful during assembly, not too strong.

Specialized lines of machinery and technological equipment are needed to manufacture and assemble the core

Only a few enterprises are capable of manufacturing this type of transformer

The manufacturing process for the amorphous steel core:

8. Amorphous Transformer Quotes

MBT is a brand of transformer products that have a high reputation in the market. With the strength of experience and technological lines in manufacturing, a good team of engineers, skilled technical workers, and abundant customer partners in many areas, so we are always leading about quality of service and price.

We design, manufacture, and supply all kinds of electrical transformers with a dedicated project manager and a 24-month guarantee from dispatch.

With the business motto: "A satisfied customer is the best business strategy of all," and over 11 years of experience in transformer design and manufacture. We, MBT, are confident of being the best Transformer manufacturer in Vietnam.

Contact immediately +84913 006 538 or email: [email protected] for a free consultation and support and receive the most preferential quotation.

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Amorphous transformer | MBT Electrical Equipment JSC

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An electrical transformer is an essential device in the distribution and transmission system of electricity in the national grid electricity system. Along with the development of technology, the transformer manufacturing industry has also overgrown in recent years.

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Facing energy on the rise worldwide, the need for friendly and reliable natural energy sources is one of the most significant challenges of our time. Besides wind and water, sunlight - clean, CO2, and infinite air - is our most valuable resource. To make renewable energy the dominant energy source worldwide, we aim to make them as affordable as conventional energy sources. By combining innovations in renewable power generation with smart grid and high voltage transmission technology, we can save even more energy and costs.
1. What is a Solar transformer?

Transformers are an essential component in the production and distribution of solar energy. There have been two main types of transformers as step-up transformer and step-down transformers from non-renewable energy sources.

For transformers used for solar projects, it is necessary to design with high durability, stable, and long-term operation. These transformers operate with low voltage input, which are solar inverters influenced by high-order harmonics, DC components generated during transport operation change the solar panels.
There are different solar transformers, including distribution, station, auxiliary station, pad mounting, and grounding. All solar transformers have special needs that affect the cost of the machine.
The solar transformers of MBT
2. Structure of the Solar transformer

The solar transformer structure is the same as an ordinary transformer's general structure, including machine enclosure, winding, and steel core.

The solar system also has particular design problems. Since the most massive solar inverter size is around 500 (kVA), the designers build a 1,000 kVA solar transformer by placing two windings connecting the inverter in one transformer's tank. The transformer must have separate windings to accept completely different inputs. Design issues also stem from the long-distance cable running to convert from DC to AC.

The inverter size restrictions also limit the size of the
PV system. Increasing in size by adding more solar inverters to a transformer tank is extremely difficult. With the required box size and running cabling to convert DC to AC, things get complicated.

Solar power systems

The key to a
solar transformer is to understand the variables in every system. The transformer needs to be customized to work with specific systems. Inverter technology is slow to be developed. It remains to be seen whether this comparative downside is a fatal flaw in advancing solar technology on a par with wind farms.

3. Principle of operation of solar transformers

Electrical energy is created by converting photoelectric energy into one dimension using photovoltaic (PV) cells. The generated direct current is converted into alternating current by a frequency converter, and the alternating current is connected to the grid by a step-up transformer. The international standard for transformers for DPV generation is IEEE C57.159 2016 "IEEE Guidance on Transformers for Applications in Distributed Photovoltaic Generating Systems (DPV)."

Currently, there are restrictions on the power rating and voltage level of the inverter system. Therefore one or more inverters are connected with an equal number of secondaries of the step-up transformers. Although the most common configuration is 2 to 3 secondary windings, it is currently possible to manufacture transformers with six secondary windings. The inverter manufacturers are presently developing inverters with higher power and voltage ratings, and this will increase the future transformer MVA rating and reduce the number of secondary windings required.

4. Design characteristics

Asymmetric load and voltage: The inverter voltage and the load current up to 3 phases of the transformer may be unbalanced. If the transformer is powered by more than one inverter, likely, one of the inverters is not working, creating an unbalanced load of the winding. Unbalanced voltages and currents can create excessive leakage currents that heat the winding inside the transformer.

Windings: The low-voltage windings that are vertically stacked with an equal number of high-voltage windings are designed to reduce the effects of the imbalance. The impedance characteristics will be determined based on the inverter system and the number of inverters connected to the transformer.

Presence of direct current in the winding: There is a possibility that a direct current can come to the inverter fed winding; this can increase the current from the core magnetization and the inrush current peak.

The waveform of the inverter output: The waveform of 2 or more inverters connected to one transformer may not be synchronized, causing harmonic and waveform changes and flux disturbances.

Transformer losses and efficiency: Solar transformers are designed with a relatively low no-load loss because the transformer gets electricity from the system at night. The efficiency at a specific load cycle is optimized for the overall operating economy. Suppose the electrical system is designed with an electrical storage facility such as a battery system. In that case, the transformer will operate under load continuously, and the efficiency level can be fixed on this basis.

Inrush current considerations: The low-voltage winding of a solar transformer is usually near the core, and therefore, the air core resistance of this coil is low. The starting current when switching on low voltage is relatively high.

Thermal design: Solar transformer cooling system is designed to consider the effect of the change of the ambient temperature at the location, the load curve, the influence of harmonics, the impact of reactive loads.

Short circuit considerations: The winding configuration and the short-circuit position on a transformer influence the short-circuit magnitude and distribution. The effects of the transformer's various short-circuit conditions shall be considered for designs, including short-circuit on the transformer's high-voltage, short-circuit on any one or more of the transformer' low-voltage and short circuit between any two low-voltage of the transformer.

Particular installation and commissioning practices: The inverters are connected to the transformer's star-connected low voltage winding. Therefore, the neutral is kept floating (the neutral is not grounded or grounded). It is a safe design practice to keep the neutral isolated inside the transformer. The transformer used has an electrostatic shield that is earthed only one point.

Optimizing the design of the losses and working temperature of Solar transformers ensures the machine operates with a reasonable day and night load cycle, reducing the device's materials and costs while ensuring durability during working.

Generating electricity from photovoltaic systems does not create carbon emissions. However, the mineral oil used for solar transformers is not environmentally friendly. Options used today are biodegradable oil-filled transformers, cast resin transformers, and dry-type transformers.

5. We renew energy

MBT Electrical Equipment JSC offers a wide range of dry-type transformers and oil-immersed transformers for solar energy applications and components, replacement parts, and services. With the transformer manufacturing basis and strict quality control process, MBT can supply and manufacture top quality transformers in Vietnam and the world.

Whether you need transformers for AC or DC voltages, 50-60 Hz and IEC or IEEE standards, MBT technologies and innovations can increase solar reliability while reducing impact environment and reducing life cycle costs.

MBT solar transformers are designed for installation in all environmental conditions. Generation units are custom designed to meet all applicable standards, regulations, and customer specifications. Oil-immersed transformer and dry-type transformers are rated for their solar generating capacity and array voltage level, meeting all applicable standards and regulations in force and energy efficiency. Oil-filled transformers can be manufactured and tested with mineral oil or liquid ester (natural or synthetic).

With the business motto: "Quality nurtures Reliability," customers who come to MBT will always receive
products with high quality, reasonable prices, fastest delivery time, and best warranty service.

Contact immediately +84913 006 538 or email:
[email protected] for free consultation support and receive the most preferential transformer quote.

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Solar Transformer | Solar Power Solutions

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Facing energy on the rise worldwide, the need for friendly and reliable natural energy sources is one of the most significant challenges of our time. Besides wind and water, sunlight - clean, CO2, and infinite air - is our most valuable resource.

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Cast resin transformer has another name that is dry-type transformer. They are the type of distribution transformer not use liquid to cool the coil but by air. Maybe you are searching for the advantages and disvantages of . You want to find complete information about their appliance to choose the right cast resin transformer for your factory. So today, we will show you the advantages as well as disadvantages of this machine. cast resin dry-type transformers
Some disadvantages of cast resin transformer

Cast resin transformer of MBT

The transformer's insulation consists of an epoxy resin and quartz powder mixture (an eco-friendly material). They prevent the winding from fire. They are almost maintenance-free, so you don't need to buy costly fire extinguishing equipment. Moreover, the cast resin transformer will also not produce toxic gases, not even effected by arcing.

It only needs air to cool the coil. Therefore, you don't need to pay extra costs and labor for liquid-level checking, oil testing, oil recycling costs, and dielectric testing for moisture absorption. Because they are almost maintenance-free, there are no oil leaks when operating, which require gasket replacements.

TIP: You should ensure that your preferred manufacturer has passed/ obtained C2/E2/F1 tests according to IEC 60076-11 or ISO 17025 like Vietnamtransformer.

Quality certifications of MBT

There are almost no restrictions when on the installation site. The closer the transformer is to the load, the lower the cable losses and cost.

Reliability: Cast resin transformers have a life cycle of more than ten years and a low failure rate when operated within its designed parameters. This makes it a highly reliable component that is suitable for any electrical infrastructure. You can contact Vietnamtransformer for more information about the cast resin transformer.

Historically, the cracking of cast resin transformers shorter life cycles, so the latest technology has introduced glass fiber reinforcement in the windings that eliminate cracking by its heating and cooling curves.

Due to flexible winding supports and design flux densities, they reduce the noise levels during operation.

By the nature of the design, cast resin transformers are more compact so that they require less space than oil-cooled units.

On behalf of advantage, there are some disadvantages of dry type transformer.

For the same power and voltage rating, a dry-type transformer is more expensive than an oil-cooled transformer.

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Cast resin transformer has another name that is dry-type transformer. They are the type of distribution transformer not use liquid to cool the coil but by air. Maybe you are searching for the advantages and disvantages of . You want to find complete information about their appliance to choose the right cast resin transformer for your factory.

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What is a Single-phase transformer: Construction and Its Working

The Single-phase transformer is a static electrical device used to change alternating voltage. The main structure of a single-phase transformer with two secondary and primary windings is converting the voltage of the AC system based on the principle of electromagnetic induction.

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The Single-phase transformer is a static electrical device used to change alternating voltage. The main structure of a single-phase transformer with two secondary and primary windings is converting the voltage of the AC system based on the principle of electromagnetic induction.
1.What is a single phase transformer?
2. Principle of single-phase transformer
3. Structure of single-phase transformer
4. Type of single-phase transformer
5. Applications of single-phase transformer

1. What is a single phase transformer?

The transformer is a device that converts magnetic energy into electrical energy. It consists of two electric coils called primary and secondary. The primary winding of a transformer receives electricity while the secondary coil is charged. A ferromagnetic circuit called a "core" is often used to wind these coils. Although the two windings are electrically isolated, they are magnetically linked.

Single-phase transformers use single-phase alternating current transformers, transformers based on voltage cycles that operate in a uniform time-phase.

A current flows through the transformer's primary winding creating a magnetic field, creating a voltage across the transformer's secondary winding. Based on the application types, single-phase transformers are used to increase or decrease the output voltage. This transformer is usually a high efficiency and low loss power transformer.

2. Principle of single-phase transformer

The alternating voltage source sends alternating current through the transformer primary winding. The alternating current creates an alternating electromagnetic field. The magnetic field line travels through the transformer iron core and includes the transformer secondary circuit. Thus the induced voltage in the secondary has the same frequency as the voltage on the primary. The induced voltage is determined using Faraday's Law.

In which,
f → frequency Hz
N → number of winding turns
Φ → flux density Wb

If the load is connected on the transformer's secondary side, current flows through the secondary winding. A single-phase transformer can act as a step-up transformer or step-down transformer.

3. Structure of single-phase transformer

The main parts of a transformer are the coil, core, and isolation. The windings should have a small resistance and are usually made of copper (rarely aluminum). They are wrapped around the core and must be isolated from it. Besides, the coils must be isolated from each other.

The transformer core is made of fragile, highly permeable steel plates. The coatings should be thin (0.25 mm to 0.5 mm) because of reduced power losses (known as eddy current losses). They must be isolated from each other, and usually, an insulating varnish is used for that purpose.

Transformer insulation can be supplied either dry or liquid-filled. Dry-type insulation is provided by synthetic resin, air, gas, or vacuum. It is only used for small-sized transformers (below 500 kVA).

Liquid insulation usually means using mineral oil. The oil has a long lifespan, good insulation properties, overload capacity, and transformer cooling. Oil insulation is always used for large transformers.

Single-phase transformers have two windings, one on the primary and the other on the secondary. They are mostly used in single-phase electrical systems. Three-phase system application means using three single-phase units connected in a three-phase system. This is a more expensive solution, and it is used in high voltage systems.
Video of Single-phase transformer:
4. Type of single-phase transformer

a. Core-type transformers

In this type of construction, only half of the windings are cylindrically wound around each leg of the transformer to enhance magnetic coupling, as shown in the figure below. This type of construction ensures that magnetic field lines run through both coils simultaneously. The main disadvantage of core-type transformers is that the leakage flux occurs due to the current of a small proportion of the flux line from the outside of the core.

b. Shell type transformer

In this type of transformer construction, the primary and secondary windings are cylindrically placed on the median limb resulting in a cross-sectional area twice that of the outer limb. There are two closed magnetic lines in this structure, and the outer limb has a flux ɸ / 2 running through them. Shell-type transformers overcome leakage flux, reducing core loss, and increasing efficiency.

5. Applications of single-phase transformer

The advantages of three single-phase units are transportation, maintenance, and availability of backup equipment. Single-phase transformers are widely used in commercial low-voltage applications such as electronics. They act as a descending voltage transformer and reduce the home's voltage value to something appropriate for the electronic device supplied. On the secondary side, the rectifier is usually connected to convert the ac voltage to the direct voltage used in electronic applications.

6. Single-phase Transformer Quotes

The Single-phase transformers of MBT

MBT is a brand of transformer products that have a high reputation in the market. With the strength of experience and technological lines in manufacturing, a good team of engineers, skilled technical workers, and abundant customer partners in many areas, so we are always leading about quality of service and price.

We design, manufacture, and supply all kinds of electrical transformers with a dedicated project manager and a 24-month guarantee from dispatch.

With the business motto: "Quality nurtures reliability," and over 11 years of experience in transformer design and manufacture. We, MBT, are confident of being the best Transformer manufacturer in Vietnam.

Contact immediately +84913 006 538 or email: [email protected] for a free consultation and support and receive the most preferential quotation.

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Single-phase transformer | MBT Electrical Equipment JSC

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The Single-phase transformer is a static electrical device used to change alternating voltage. The main structure of a single-phase transformer with two secondary and primary windings is converting the voltage of the AC system based on the principle of electromagnetic induction. 1.What is a single phase transformer? 2.

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Distribution transformers are an essential asset in the first and last step of the grid. In traditional electrical networks, they are used to convert the high voltage transmitted into a low voltage that can be used in industries, infrastructure and households. With the rise of decentralized generated electricity, they are now also responsible for supplying power to the grid.
1. What is a Distribution transformer?

A distribution transformer is also referred to as a typical isolation transformer. The main function of this transformer is to convert the high voltage into normal voltage like 240/120 V for use in power distribution. In the distribution system, there are different types of transformers , such as single-phase , 3-phase, underground, pad-mounted, pole-mounted transformers .
Distribution Transformer
2. Structure of Distribution transformers

A distribution transformer has the same structure as an ordinary transformer . The main parts of this transformer are mainly composed by Oil Tank, Conservator, Buchholz Relay , Breather Unit, Oil Indicator, Temperature Detector, Pressure Relief Device, Thermal Relay, Radiator, and Bushing.

- The oil tank is used to soak the coils by placing it in.

- The breather unit includes desiccant silica gel in the oil. If it changes its colour from blue to pink, it will not be hygroscopic in oil.

- The temperature detector monitors the temperature of the oil. If the oil temperature rises to a certain level, the transformer will be disconnected from service.

- The pressure relief device reduces the pressure inside the transformer to prevent an explosion from the transformer.

- Radiators are used to increase the cooling efficiency of the transformer.

3. Types of Distribution transformer

These transformers are specially used for networks where three-phase supplies are not required. Usually, they are used to repair overhead distribution loads in residential areas. They are also applicable in industrial lighting, light commercial loads and electrical applications.

A three-phase transformer is used to hold electrical energy from the main distribution circuit to the auxiliary distribution circuit. It transmits current to the secondary distribution circuit and at the same time reduces the voltage of the primary distribution circuit. These transformers reduce the voltage supplied to the primary circuit based on consumer requirements.

This voltage is always variable and can vary for commercial, residential and light industrial users. These transformers operate at different voltage and frequency levels based on existing standards in other countries. These transformers are available in single-phase and three-phase. Single-phase is used in civil applications while with a pad is used in underground primary circuits.

The pad-mounted transformer consists of a locked steel cabinet located on a concrete base. This type of transformer is installed in places where they do not have space for the . This transformer is used with the power distribution line on the overhead power line to reduce the primary voltage supplied to the customer. A single transformer of this type can be used for multiple homes / a large building. The capacity of this transformer ranges from 75 kVA to 5000 kVA and includes stationary switches & fuses.

The transformer' tank can be shaped and protected from corrosive materials and water accumulation. In coastal areas, tanks can be protected by zinc spraying while in highly corrosive areas, stainless tanks are used.

4. Purpose of using Distribution transformer

This transformer changes from high voltage to low voltage, used in homes and businesses.

The main function of this is to reduce the voltage to provide isolation between the two windings as primary and secondary.

This transformer distributes electricity to remote areas generated from power plants.

Generally, this transformer distributes electrical energy to industries with less than 33KV voltage and 440V to 220V for domestic purposes.

5. Difference between Power Transformer and Distribution Transformer

Power transformers used in transmission networks have a higher voltage for ladder and step applications (400 kV, 200 kV, 110 kV, 66 kV, 33kV) and are typically rated above 200MVA.

A
distribution transformer is used for the lower voltage distribution network as a means of connecting end-users. (11kV, 6.6 kV, 3.3 kV, 440V, 230V) and generally rated below 200 MVA.

b. Transformer size and insulation level

The power transformer is used for transmission at heavy loads, a high voltage greater than 33kV & 100% efficiency. It is also larger in size than distribution transformers; it is used in power generation stations and transmission substations-high insulation level.

Distribution transformers are used to distribute electrical energy at a low voltage below 33KV for industrial purposes and 440v-220v for residential purposes.
It works with low efficiency at 50-70%, small size, easy to install, has a low magnetic loss and it is not always fully loaded.

The main difference between a distribution transformer and a source is that a distribution transformer is designed to achieve maximum efficiency at 60% to 70% load because normally not always operating at full load. Its payload depends on the demand for distribution. Whereas a transformer is designed to achieve maximum efficiency at 100% load as it is always running at 100% load near the generating station.

Distribution transformers are used at distribution levels where voltages tend to be lower. The secondary voltage is almost always the voltage supplied to the end consumer. Due to voltage drop limitations, it is often not possible to provide that secondary voltage over large distances.

Consequently, most distribution systems tend to involve multiple 'clusters' of loads fed from the
distribution transformer , and this means that the distribution transformer heat rating does not have to be too high for support the load they must serve.

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Distribution Transformer | MBT Transformer

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Distribution transformers are used for lower voltage distribution networks as a means to end-user connectivity.