Comprehensive Guide to 18MVA to 90MVA Transformers

Electrical power transformers are the most common types of equipment used for power electricity, typically ranging in power ratings from 18 MVA to 90 MVA. They operate at voltages between 44 kV and 230 kV and are available in either a three-phase or single-phase configuration. These transformers can be either on-load tap-changing or off-circuit tap-changing. They are commonly used in power transmission and substations. The key features of these transformers include high resistance to short circuits, low levels of partial discharge, minimal noise, low energy loss, and quiet operation.

Daelim is a professional manufacturer of power transformers, with over 20 years of experience serving the American market. They specialize in providing transformers with power ratings ranging from 18 to 90 MVA. Daelim's transformers come with UL, cUL, CSA, and other certifications, ensuring their high quality and compliance with safety standards. Their commitment to delivering reliable and professional services has earned them recognition from customers in the United States, Canada, and other countries.

So now, we'll talk about power transformers that have rated power from 18 MVA up to 90 MVA. We're going to go through exactly what they are and how you can put them to use.

Table of contents

What Is The Electrical Design For 18 MVA To 90 MVA Transformers?

18mva 66kv transformer
The cooling methods, elevated temperature, installation, and vector grounds are all factors that should be always taken into account when designing the electrical aspect of a transformer.

Cooling Methods And Power Output

If just one power rating is essentially given for a transformer, it is also believed that the transformer applies natural oil-air cooling (ONAN or OA).

If there are two ratings, either ONAF or FA (two-stage forced air cooling) is necessary.

Elevated Temperature

According to standards, the following temperature increase of 18 MVA to 90 MVA transformers limits must be primarily met by power-rated units.

40 °C Max temperature
30 °C average in 1 day
20 °C average in 1 year
–25 °C lowest temp outdoors
–5 °C lowest temp indoors

Installation

The maximum height at which these transformers can function is 1000 meters. If your location is generally located at a greater altitude than 1,000 meters, you will need to upgrade your transformer.

Vector Groups

Large power transformers and generating transformers such as 18 MVA o 90 MVA frequently utilize Yd wiring. The neutral's protection drops off rapidly after 110 kV of HV windings.

Learn more about Transformer Design

What Is The Mechanical Design For 18 MVA To 90 MVA Transformers?

Mechanical design considerations, such as the transformer's tank and oil preservation system, are essential to the manufacturing process.

Tank Design

A conventional sealed-tank distribution transformer, this model can handle ratings of up to 18 MVA and 90 MVA with a conservator.

Transformer oil is always included in the shipping and packing. Swapping out bushings can be also done from the outside of the machine without having to drain the oil from the moving part.

General Mechanical Design:

Mechanically designed iron core, electrically insulated sheet steel with a grain orientation
Both copper wire and copper strip can be generally used for copper windings.
Has a short circuit tolerance of at least 2 seconds (IEC).
This radiator tank/oil storage container is perfect due to its sturdy corrugated sides.
Transformative bottom wheels that are either flat or flanged
The mineral oil that meets the standards of VDE and IEC is mainly utilized as the cooling and insulating fluid.
Designed for usage in the wild or other untraditional settings, these surface treatments can withstand the elements.

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What Is The Connection Systems For 18 MVA To 90 MVA Transformers?

mva transformer connection
To convert electrical power into a magnetic field, most transformers with ratings between 18 MVA and 90 MVA have their main windings linked to the input voltage source.

In contrast, the secondary winding is in charge of converting the alternating magnetic field into the necessary amount of electrical power to provide the output voltage.

Connectivity System

The external bushing is the most typical connection for 18 MVA to 90 MVA transformers.

The transformer bushings can be generally supplied vertically, horizontally, or at an angle, depending on the voltage, current, system circumstances, and transport requirements.

DIN stipulates that oil-filled bushings are safe up to 110 kV, even though condenser bushings are typically used at higher voltages.

To save space or maintain a certain aesthetic, it is often essential to route wires straight to the transformer.

For systems with voltages below 30 kilovolts, air-filled cable boxes are acceptable.

When the oil fills the housings, it effectively insulates them from the higher voltages. You're free to mount them wherever you choose on the tank.

Reading more about Transformer Connection

How Do You Evaluate the Causes For Transformer Loss Between 18 MVA and 90 MVA?

Rising power rates mean that customers should be careful not to squander money on unnecessary units.

Distribution and power transformers rating from 18 MVA to 90 MVA, which are frequently utilized under load and must work constantly, would benefit greatly from this.

In many cases, the savings in energy costs from using loss-optimized transformers may pay for the equipment's initial cost in under three years.

This simple method may be primarily used to quickly compare the prices of various stated transformer losses.

The transformers are generally used all the time.
Transformers work with a partial load, but this partial load is always there.
Extra costs and inflation are not taken into account.
Demand fees are usually based on a full load.

Low-loss transformers like 18 MVA to 90 MVA, have a higher recommended retail price because they use more expensive components.

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MVA Power and Specifications: 18MVA to 90MVA Transformers

Daelim's 18 MVA to 90 MVA transformer features innovative quality made with premium materials and components to provide dependable quality and long service life.

Moreover, power transformers manufactured by Daelim are highly assembled in China and are highly built to deliver with complete confidence in any part of the world.

They have 18 MVA to 90 MVA transformers that are specifically developed to fulfill or surpass the standards and requirements that are applicable at the local, regional, national, and worldwide levels.

If you are looking for MVA transformers of the greatest possible quality, Daelim is the firm you should trust.

Let's identify and discover each one.

Read my article on The Ultimate Guide to 4-16 MVA Transformers

How Much Power And Specification Does An 18 MVA Transformer Have?

18 MVA power transformer has an 18000 kVA. This 18000 kVA Step Down has ratings of 66/13,8kV.

Daelim's 18MVA low-loss series transformer is a new generation of transformers that were generally created in-house using domestic and international innovative technology.

18 MVA transformer has a high level of dependability, odd protection against abrupt short circuits, and strangely low levels of local discharge, loss, noise, and noise.

Rated Power: 18 MVA
Equivalent KV: 18,000 KVA
Frequency: 50/60Hz
Phasing: Three
Cooling Type: ONAN/ONAF
Main Voltage: 230 kV/220 kV/138 kV/110 kV/69 kV
2nd Voltage: 11 kV/35 kV66 kV//69 kV
Vector Group: YNd11
Impedance: 11-14%
Tap Changer: OLTC/NLTC
Tapping Range: ±8*1.25%
Accessories: Standard Config
Construction: Copper/Aluminum

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How Much Power And Specification Does An 25 MVA Transformer Have?

A 25 MVA transformer has a 24.9 kV primary winding and a 4.16 kV secondary winding(the transformer Daelim exported to the United States). It can handle electricity demands up to 25000 kVA.

As you can see, power distribution in bigger, more diverse areas is best served by 25 MVA transformers.

They make it easier to switch from the electricity provided by the utility grid to that provided by alternative sources, such as generators.

Daelim has maintained a 100% approval rate for more than a decade, guaranteeing that every transformer it ships has been thoroughly tested.

Rated Power: 25 MVA
Equivalent KV: 25,000 KVA
Frequency: 50Hz
Phasing: Three
Cooling Type: ONAF
Main Voltage: 24.9 KV
2nd Voltage: 4.16KV
Vector Class: Dyn11
Impedance: 6.5 %
Tap Changer: OLTC
Tapping Range: +10% in steps of 1.25% 7 tapping
Accessories: Standard
Material: Copper
No Load Loss: 8 KW
On-Load Loss: 66.5 KW

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How Much Power And Specification Does An 31.5 MVA Transformer Have?

A 31.5 MVA transformer has 11 kV secondary windings in addition to its main 132 kV primary winding. It can handle power demands of up to 31,500 KVA.

As a result, 31.5 MVA transformers are the best option for distributing power across wider, more diverse areas.

It can hold around 11600 kg of oil and weighs around 48000 kilograms. Because of its low flux density and magnetic shields, it can withstand high over-excitation without being highly damaged.

Rated Power: 31.5 MVA
Equivalent KV: 31,500 kVA
Frequency: 50Hz
Phasing: Three
Cooling: ONAN
Voltage Ratio: 132000 / 11000 V
Voltage Regulation: OLTC - On-load Tap Change
Tapping Range: +-12x1,5%
Connection: YNyn0
Material: Copper

How Much Power And Specification Does An 35 MVA Transformer Have?

35 MVA transformer has a main winding that is usually rated at 110 kV and a secondary winding that is mainly rated at 66 kV.

It can accommodate electrical loads of up to 35,000 kVA at a time.

In total, it can transport 13,500 liters of oil and weighs 55,000 kilograms.

35 MVA transformer is frequently utilized in large buildings because they are dependable and satisfy the electrical requirements of the structure.

Rated Power: 35 MVA
Equivalent KV: 35,000 KVA
Frequency: 60Hz
Phasing: Three
Cooling Type: ONAN
Voltage Ratio - HV/LV: 66000 / 11000
Voltage: Off-circuit tap changer
Tapping Range: +-2x2.25%
Material: Copper

How Much Power And Specification Does An 45 MVA Transformer Have?

45 mva transformer

A 45 MVA transformer has a 132 kilovolt (kV) primary winding and an 11 kV secondary. The internal fans and OLTC in this transformer keep things cool.

It can handle electrical loads of up to 45,000 kVA.

It has a massive weight of 23000 pounds and a storage capacity of 5100 kg of oil. In either case, accessories are flexible.

To reduce the high voltage from the transmission line to a level that may be mainly used in homes and businesses, a 45 MVA transformer is frequently applied.

Rated Power: 45 MVA
Equivalent KV: 45,000 KVA
Frequency: 50Hz
Phasing: Three
Cooling Type: ONAN/ONAF
Main Voltage: 132 kV
2nd Voltage: 11kV
Vector Class: YNd1
Impedance: 13%
Tap Changer: OLTC
Tapping Range: +4*1.25%, -12*1.25%
Material: Copper

How Much Power And Specification Does A 60 MVA Transformer Have?
Oftentimes, the primary voltage of the 60 MVA transformer is 242 kilovolts, and the secondary voltage is 10.5 kilovolts.

It can manage electrical loads of up to 60,000 KVA without any problems. This high-voltage power transformer incorporates an ONAF cooling system into its design.

A 60 MVA transformer typically weighs close to 108,000 kilos.

Moreover, a 60 MVA transformer is typically found in power plants and is primarily used to boost the voltage of the electricity generated by the plant before it is mainly distributed across the grid.

Rated Power: 60 MVA
Equivalent KV: 60,000 KVA
Frequency: 50/60Hz
Phasing: Three
Cooling: ONAF
No load loss: 28kw
On load loss: 265kw
Vector Class: YNd1
Impedance Rate: 13.3%
Tapping Range: NLTC a±2*2.5%
Material: Copper

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How Much Power And Specification Does A 70 MVA Transformer Have?

A 70 MVA transformer has a main winding that generates 220 kV and a secondary winding that generates 30 kV.

Power demands of up to 70,000 kVA can be usually met without any difficulty.

70 MVA transformer is a high-voltage power transformer with ONAN and ONAF cooling systems in mind.

The massive tank of a 70 MVA transformer carries up to 38,200 kilograms of oil and weighs in at a whopping 131,000 pounds.

Rated Power: 70 MVA
Equivalent KV: 70,000 kVA
Frequency: 50/60Hz
Phasing: Three
Cooling Type: ONAN/ONAF
Tapping Range: +-8x1.25%
Temperature Rise: 50/55 K
Connection: YNyn0
Tapping Range: NLTC a±2*2.5%
Material: Copper
Tap Changer: OLTC

How Much Power And Specification Does A 90 MVA Transformer Have?

A 90 MVA transformer's primary and secondary windings may produce 11 kV and 110 kV, respectively.

Electricity may be consistently supplied up to 90000 kVA.

This high-voltage, 90 MVA power transformer is specifically designed to run with the high voltage required by ONAN and ONAF air conditioners.

Moving this 90 MVA transformer requires careful planning and the completion of multiple phases. Mostly due to the size and weight (110 tons).

Rated Power: 90 MVA
Equivalent KV: 90,000 KVA
Frequency: 50/60Hz
Phasing: Three
Cooling Type: ONAN/ONAF
Temperature: 60/65K
Impedance: 14 %
Material: Copper
Vector Class Dyn11/ Yyn0
Insulation: Mineral Oil
Transport: Wooden Pallet, Wooden Case

Comprehensive Guide to 18MVA to 90MVA Transformers