2022 Ultimate 11kV Transformer Guide

2022 Ultimate 11kV Transformer Guide

There are different classifications of transformers, one of which is based on the purpose of using them.  One type based on use is a power transformer that regulates electrical power with a high rating. An 11kV transformer is an example of a power transformer.

Transformers work to improve the efficiency and safety of electrical power systems by stepping up or stepping down voltage levels as needed.

They are mainly used for power regulation and distribution in most residential and industrial applications, especially long distances.

DAELIM is the world’s top professional transformer and electrical equipment manufacturer.

This company has been a reliable and trusted brand for more than 15 years. DAELIM upholds international standards with inexpensive and premium products.

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What Is 11kV Transformer?

An 11kV transformer is a power transformer that regulates and distributes electrical power at a safe voltage level in residential areas.

These power transformers feed local transformers responsible for distributing power to different buildings in a specific area.

The 11kV transformer diagram above illustrates how power is regulated at substations from high voltage to an appropriate level for local distribution.

A single line diagram of 11kV transformers makes the reading of the electrical power supply and connection easier.

Types of 11kv transformer

What Are The Standard Features Of An 11kV Transformer?

The standard features of an 11kV transformer include the phase design and the cooling design.

These features are important determining factors in choosing the right 11kV transformer to suit the type of power transform you need.

Phase Design

The phase design of 11kV transformers can either be single-phase or three-phase.

These two-phase designs differ mainly on the number of windings required to achieve the voltage transformation you need for your electrical power.

11kV single-phase transformer
11kV single-phase transformer

11kv Single-Phase Transformer

11kV single-phase transformers consist of one primary and secondary winding, each for voltage transformation.

These two coils are highly inductive that are wound on a steel or iron core.

The winding attached to the AC supply is the primary or first winding, while the other is the secondary winding.

Single-phase transformers are applicable for residential areas where they serve as step-down transformers.

They convert high voltage to low voltage levels, which are suitable mostly in residential and office applications.

They are also suitable for domestic and light commercial purposes because of their low cost and low electricity input requirements.

Other benefits of single-phase transformers include:

  • Less complex design
  • Design cost is less
  • Enhanced efficiency in delivering 1000 watts AC power supply
11kv Three Phase Transformer
11kv Three Phase Transformer

11kv Three-Phase Transformer

On the other hand, 11kV three-phase transformers consist of six coils, three on the primary and three on the secondary.

Each of the coils is separated from the other by a 120 angular difference.

To achieve accurate voltage levels, these transformers are placed in enclosures crammed with dielectric oil.

Three-phase transformers have higher efficiency to supply electrical power in heavy-duty applications such as industrial areas.

Some of the benefits of using 11kV three-phase transformers include:

  • Less copper for power supply
  • Operating bears minimal risk
  • Enhanced conductor efficiency
  • Function well with long-distanced power ranges

Cooling Design

The cooling design of transformers is an important feature to keep them functioning at an optimum level.

Generally, there are two kinds of cooling designs: oil-cooled and dry-type transformers.

11kV dry-type Transformer
11kV dry-type Transformer

Dry-Type 11kV Transformer

Dry-type 11kV transformers mainly use air as a cooling medium. Air is utilized by using vacuum pressure impregnation in any of the following:

  • Polyester
  • Silicone varnish
  • VPI epoxy
  • Cast resin for harsh environmental conditions

The maximum voltage for dry-type transformers is 33kV.

They are generally the transformers of choice for indoor applications such as shopping malls and hospitals because dry-type transformers are environmentally safer and do not pose a fire risk.

11kv Oil-Cooled Transformer
11kv Oil-Cooled Transformer

Oil-Cooled 11kV Transformer

Oil-cooled 11kV transformers immerse the coils in mineral oil to maintain optimal temperature for the transformers’ maximum function.

The oil dissipates throughout the radiators, which are attached to the transformer tanks.

These kinds of transformers are more suitable to place outdoors because of the possible risk of oil spillage.

They are also more eco-friendly because they produce less waste and have better working efficiency and maintainability.

Other Features

11kV transformers have other features that make them efficient in distributing electrical power. These other features include the following:

  • Produce less noise
  • High efficiency-energy saver
  • Strong built
  • Less power loss
  • Good operational reliability

Where To Use 11kV Transformer?

11kV transformers are commonly used to regulate voltage levels used in residential areas.

They are used to step down voltage levels from high voltage transmission lines to transmit electrical power to local feeders.

From the local feeders, power is distributed to the buildings in the same residential area.

11kV transformer application
11kV transformer application

How To Conduct 11kV Transformer Installation Procedure?

11kV transformer installation procedure involves the general guidelines in installing most electrical transformers.

These guidelines are listed below.

Do standard and specialized transformer testing

To ensure that transformers are in perfect condition, you should remember to do different standard and specialized tests for your transformers, such as:

  • The ratio for voltage relationship
  • Polarity for single or three-phase transformers
  • Phase relationship for three-phase units
  • Excitation current
  • Resistance to calculate the winding temperature
  • Impedance
  • Load loss for transformer efficiency
  • Regulation to determine voltage drop during load application
  • Applied and induced potentials

Site Considerations

The location of the transformer should be carefully selected.

It should not interfere with the normal movement of personnel and material.

They should also not be exposed to possible damage from cranes, trucks, or moving equipment.

Plan for contaminant prevention

You must have all the tools and hardware you need to inspect, assemble, and test your transformer.

Control the transformer sound level

Learn to control the transformer noise, especially when you install it in quiet hallways.

Transformer hums will be noticed when they are installed in areas that are commonly quiet with fewer people.

Ensure that the transformer is grounded

Grounding is a necessary step in the wiring of a transformer and should be carried out before the circuit is energized.

It removes any static charge and protects the transformer if the windings contact the transformer core or enclosure.

Other Guidelines

Other important guidelines to note when installing 11kV transformers include:

  • Making operational and functioning connections
  • Preliminary inspection
  • Final inspection and testing
  • Applying the power load
  • Adjusting for proper tap setting

What Is an 11kv Feeder?

An 11kV feeder is a three-phase, three-wire distribution line with 11kV voltage power.

It begins at the first substation and traverses villages and agricultural areas in rural areas to reach agriculture, households, and other small businesses.

11kV feeders commonly exceed 10km and terminate across another one from a different primary substation.

Some feeders also terminate in areas where there are no end-users.

Along 11kV feeders are 11kV/433V distribution substations that step down the voltage from 11kV to 400V.

This voltage level is used to supply agricultural water pumps and other industrial equipment.

What Are HT And LT?

Typical thermal evaporation units have two kinds of power supplies: HT and LT power supply.

HT Power Supply

HT power supplies provide high voltage for plasma growth cleaning and DC sputtering.

These power suppliers are step-up transformers that build up the high kV and rectifiers that convert the stepped-up AC voltage to DC.

LT Power Supply

LT power supplies provide a high current at low voltage.

They consist of step-down transformers which produce low voltage and high current at the secondary.

Is 11kV High Voltage?

The International Electrotechnical Commission and its national counterparts define high voltage as above 1000 V for alternating current and at least 1500 V for direct current.

Following this definition, 11kV is considered high voltage because it has more than 1000V for the alternating current.

Furthermore, transformers with high voltage levels pose a risk in electrical arcing.

Final Say

11kV transformers are essential in supplying electrical power for your appliances and other equipment in residential areas.

They can either be single-phase or three-phase with cooling designs of either oil-cooled or dry-type.

During 11kV installation, remember the general guidelines for installing transformers to minimize problems and unforeseen injuries and accidents.

At Daelim, we guarantee safe and high-quality transformers that are affordable and worth your money.

Our products follow international standards and are certainly durable and long-lasting.

About Bin Dong

Hello, I am Bin, General manager of Daelim which is a leading transformer manufacturer. If you have problems when you are looking for the equipment, what you need to do is tell us.

Custom 11kV Transformer

If you find that the existing 11kV Transformer types or power cannot meet your requirements. You can choose to tell Daelim. Daelim has a team that has always had a wealth of design 11kV Transformer and can give you a specific design plan in the shortest time.

Daelim’s distribution transformers comply with IEEE, ANSI, CSA, IEC certification, and are used in North America (such as Canada, the United States, Mexico), South America (such as Ecuador, Chile), Europe (such as Spain, Lithuania) and some Asian countries. Daelim even has a professional installation team that can provide you with installation services.