Substation transformers go out of stock fast, which is why a lot of consumers are considering compact substation transformers like the 11kv compact substation as their alternative for a unit substation transformer. But are they really worth considering? In this article, you will be given the compact substation specifications including the compact substation components.

With professional help from DAELIM, an expert compact substation transformer manufacturer from China, you will be provided with the essential details you need to know about compact substation transformers before making a purchase decision.

But before going through the compact substation specifications and compact substation components, it is best to understand first what substations are so that you can easily understand the terminologies and definitions involving compact substation transformers.

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What are Substations?

Substations are generally like actual commute or public vehicle stations. This is because like people, there is a need for a public vehicle to get to the location. When it comes to the situation of electricity, substations like compact substation transformers are commonly used for transporting electricity at long distances.

The place of the substation is where electricity is being produced, and it also can be the location where the consumer is found. When it comes to the spread of electricity, it is rated as a very fast and high voltage with low currents.


500kV Main Transformer in Hydropower Station
500kV Main Transformer in Hydropower Station

The purpose of this is to lower the eddy currents, transmission losses, heat, etc. These substations including the compact substation transformer and 11kv compact substation, are where the voltages ais being used to raise high valuer. This can be achieved with the help o step-up transformer.

After the transmission, they step down from the distribution once again. Moreover, these substations have a good spectrum of protective devices as well such as fuses and breakers. The main function of these two is to provide the security that is needed by the consumer.

Normally, these devices are designed with numerous distribution circuits that can be used for maintenance and even load shedding. Like most, transformers or substations, these are located outdoors like pole-mounted transformers and pad-mounted transformers.

However, compact substation transformers are commonly found in public with a wire fence in them. Moreover, these are protected inside the building, and the purpose of this is to limit the noise.


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What are Substation Transformers?

Substation transformers like compact substation transformers and 11kv compact substations are basically designed for the installation of three-phase transmission and distribution systems. This goes to show that these substation transformers are capable of being used both for indoor and outdoor purposes.

The best example of this are ground-mounted transformers or pad-mounted transformers. This can be both with high and low-voltage cables that enter operating compartments through enclosed sidewall mounted bushings or through cover or sidewall mounted bushings for open type transformers.


Compact Substation Transformers (2)
Compact Substation Transformers (2)

When it comes to liquid-filled filled substation transformers or oil-filled ones, these are commonly used for various applications due to the utility and industrial applications it is capable of performing. These step-down transformers are also manufactured in accordance to the I.E.E.E standards.

Substation transformers also have different types of oil for their cooling medium. For instance, silicone transformer oil, which is the alternative for mineral oil or commonly known as “transformer oil”.

In terms of the primary voltages of a substation transformer, this usually ranges from 2.4 kV to 69 kV in 225 through 20k kVA sizes, but 600V can go through 35kV through the secondary voltage ratings that are available.

Electrical substations are also part of the electrical installation that includes the terminations of the transmission or distribution lines. Moreover, this also involves the switchgear in which can also include transformers and all the necessary devices for the safety and control of the operation.

But the function also plays a vital role in this and it can be defined through transforming, conversion, distribution, or transmission substation. 

A medium voltage and low voltage transformer electrical substation is a set of devices that dedicate the transformation of the voltage that is provided by the distribution network through medium voltages into voltages that value compatible power for the supply of the low voltage lines.

Electrical substations can be divided into two types when it comes to their environment or surroundings, namely private and public substations.

What are Public Substations?

Aside from the fact that public substations are basically substations that are for outdoors only, this type of substation belongs to the electricity distribution company. Their common role is to supply power to the users through single-phase or three-phase alternating current or better known as “A.C”

This is also the typical voltage of the two types of power supply that can either be 230V or 400V. This is then divided into urban or rural substations, and it could consist of only one transformer (it could also be small),

Urban substations are typically built in brick, wherein rural ones are installed directly on the MV pylon.

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unit substation transformer
unit substation transformer

What are Private Substations?

On the other hand, private substations are also known as terminal type substations like substations that the MV line ends on the installation point of the substation itself. Moreover, they are also owned by the owner which means they can produce both civil users and industrial users from the public MV grid.

Furthermore, the user must make available to the distributing company a special room that is accessible to the staff of the company, wherein the equipment is from the company is responsible for it, Like other transformers, private substations can have different design solutions that can be ordered from the consumer. But nowadays, the use of prefabricated substations is common.

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What are Compact Substation Transformers?

Electrical unit substation transformer systems including compact substation transformers and 11kv compact substations play a crucial role in the distribution of electricity. But this is not the sole purpose of the transformer itself. As you might know, even compact substation transformers are capable of many things.

compact substation transformers even have bus bars to divide the power of the distribution. These bars of copper are linked by bolts and nuts and there are numerous circuits associated with them.

As mentioned, there are safety devices in these substations as well, such as fuses and circuit breakers. These devices are great for safeguarding the machinery on the distribution circuit.

Compact Substation Transformers (5)
Compact Substation Transformers (5)

Moreover, they are also great for high short circuit currents.

The alteration of power circuits has to be sustained at the right amount of value in the case there are reactive loads present.

When the power demand is more than the supply, the compact substation will then perform load shedding on the distribution circuits automatically.


How do Compact Substations Work?

When it comes to how compact substation transformers work, switching is a vital function of compact substations, this is because you can close down a feeding circuit when there is a demand for the load to secure the generating plants.

Moreover, switching high voltages can be dangerous, circuit breakers like oil circuit breakers and air circuit breakers are great for lowering arcs that can be utilized too.

Step up and step down of the voltage for the distribution and transmission power can be transported through high voltages at even long distances. This means the current can be low and this leads to low transmission losses.

This means the this does not offer the right current for normal consumer use, this means that there is a need to either step up or step down the voltage.

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Where are Compact Substations Commonly Used?

So where are compact substation transformers commonly used? Basically, they can be used for almost any application. The common applications for compact substation transformers are schools, facilities, streets, subdivisions, construction sites, malls, hospitals, and so on.

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How does compact substation work?

In terms of how substation operations or how a compact substation transformer works, electricity will be produced with a thermal power plant which means that this includes nuclear power plants and hydroelectric power plants.

Electricity is provided to a transmission substation that is close to a generating plant. Transmission substations raise the voltage greatly with the help of step-up transformers.

The electricity that is being supplied to the power station will be stepped down as well with help of step-down transformers.

Moreover, substations will be supplied to a substation grid. There are other voltages and transformers out there that are lowered for the grid. From that point on, the electricity will be supplied by step-down transformers that are close to residential sites.

compact substation transformers may be small but this type of substation consists of a total set of power distribution equipment that is composed of a voltage control device and a transformer.

The idea is actually quite simple, which is to operate substantial assembly that is rooted on the preferred sequence of the armoring line, pressure starting system, substation automatic system, etc.

A typical transformer has a build that is completely closed with a tempered cabinet structure. Nowadays, compact substation transformers are now widely used in power engineering construction.

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Compact Substation Specifications

When it comes to compact substation specifications, this type of transformer is not your ordinary transformer. Instead, they are somewhat like small substations that offer power directly to its user.

power transformers detail

Better Cooling System

Unlike typical transformers, the way a transformer operates is that an underground cavern is to increases the demand for its cooling capabilities. This means that these transformers are able to withstand spikes of voltages and load.

This means that traditional air-cooling is not that reliable, this is why water-cooling systems were invented.


Installing transformer banks of about three 500kV autotransformers is a common issue. This is why when it comes to space, the compact substation transformer is very useful. However, does it compromise its power? The short answer here is – No. compact substation transformers can be just as powerful as normal substation transformers under specific situations. 

Fewer Losses

The compact substation specifications when it comes to voltage levels are simply on another level because the requirements for the short-circuit strengths are great for requesting, Every single transformer should be able to withstand a certain amount of short-circuit load.

But his means that the autotransformers for underground substations can stand impedance of more or less 22 percent. Basically, this means that the unit substation transformer will operate at a normal pace even if it’s exposed to a load that is 22 percent higher than the usual rates. 

Better Control

There is without a doubt there is a high impedance that is being showcased challenges for stray loss control, and this is fully supported by a 3D magnetic model that shields its structure design especially when the tank and clamping frame increases.

Miniature Substation

What are the Components of Compact Substation Components?

Now that we have reached the compact substation components, the equipment of compact substation transformers can be closed in an indoor space. This means that even in both cases, the installation of the compact substation transformer will follow the international safety standards, and as well as the local P.P.C

Moreover, every facility must have specific requirements and needs that must be considered for every customer.

The common safety protectors for compact substation transformers are fuses and circuit breakers. Moreover, they also have load shedding, repairs, lightning arresters, high voltage busbars, and many more.

For special requirements, there could be a metering device, low voltage busbar, low voltage circuit breaker, and many more. This depends on the customer’s personal preference.

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Miniature Substation

Final Thoughts

The purpose of compact substation transformers is basically to step down high voltages from the transmission system. This means that their function is to reduce the voltage electricity so that it could be supplied to the consumers with ease.

If you are looking for a compact substation transformer that is specifically for this purpose, then there is without a doubt that compact substation transformers will be an excellent choice for you! 

For questions and clarifications, do not hesitate to contact DAELIM’s team of professionals for immediate assistance.

About Bin Dong

Hello, I am Bin, General manager of Daelim which is a leading transformer manufacturer. As a expert, I am glad to share my experience in transformer to you. I believe our professional team can always provide you with high quality service and we are ready to provide you with one stop solution. If you have problems when you are looking for the equipment, what you need to do is tell us.

Custom Compact Substation Transformer

When you need to find more than just existing transformers, Daelim’s Transformer Service Center can help you design and produce distribution transformers that meet your unique needs.

We have our own factory and a professional team of engineers, which can design and modify application requirements that meet all your conditions.

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