Substations have been around for many decades, and as time continues to move forward, more and more versions and modifications are being done to this electrical device. Mini substations are designed to be smaller than regular substations with a less kVA rating (kilovolt ampere). Mini substations are normally designed to have transformers that have oil in them. But nowadays, with the introduction of dry-type transformers, substations and mini substations have turned the market.
With less risk and safer for public usage, there are now many types of substations and mini substations out there that serve different purposes with new mechanisms and functions.
In this article, DAELIM, one of the best mini substation manufacturers in China, has been specializing in mini substations for over 15 years. will help you understand the many different types of substations and mini substations in the market, and we will be focusing on mini substation prices and their structure, we will also give you an example: 315 kVA mini substation.
For starters, the basic definition of mini substations is that they are the smaller version of regular substations. However, in terms of performance, both have distinct differences.
Mini substations have a smaller build design with a lower kVA rating (kilovolt ampere), thus making mini substation prices less expensive compared to typical substations. But prices may vary depending on the manufacturer.
Mini substations are essential for transmissions and distribution systems due to their regulatory functions.
They can also be used as transformers because of their transforming voltages capability. They can convert voltages that are at high levels to low voltages. In addition to that, they can also do the same to low voltage levels, and turn them to high-voltage levels.
Electrical current can pass through mini substations at different voltage levels between power generation stations and the consumers (houses, buildings, etc.).
This function alone is a heavy contributor to the mini substation’s price.
But mini substations may or may not include transformers to transform voltage levels. The primary function of this is to turn voltage levels to their assigned levels.
For instance, high transmission voltages, lower distribution voltages, and the interconnection of two transmission voltages.
Substations and mini substations are generally composed of switchgear, protective parts, control panels, and they may or may not have a transformer.
For wide substations, these substations utilize or make use of circuit breakers to stop short circuits or overloading currents that can happen on the network.
On the other hand, mini distribution substations can use recloser circuit breakers for safety purposes, as well as fuses. This is because substations usually do not have any generators. But there is most likely a power plant nearby.
Aside from power plants, the presence of other electrical devices may be possible as well such as voltage regulators, reactors, capacitors, etc.
Substations and mini substations can be placed on land and underground. For substations and mini substations that are on the surface, they are normally enclosed in tall fences. There are also outdoor and indoor substations and mini substations.
Each of which serves different functions and purposes. For instance, indoor substations are commonly found in urban locations to avoid disturbing the public from loud noise. Although this can be modified as well.
Other than that, they are used in urban areas because it protects the switchgear from natural disasters and other outside elements.
It is essential to install an earthing or grounding system to the substation to avoid injuring people that are in the vicinity during or if ever a short circuit in the transmission system occurs.
Ground faults or earth faults from mini substations and substations can cause a ground potential rise. The currents that are flowing in the ground or earth’s surface can cause objects to receive the currents and potentially pass through more objects.
For humans, you can get electrocuted by this, which can be dangerous if the voltage levels flowing in the ground are high.
This is the reason why substations and mini substations have fences around them that are precisely grounded to keep this hazard as far as possible from the public and to passers-by.
When it comes to choosing the area of where to place your substation or mini substation, keep in mind that there are several factors you must consider first before proceeding.
For starters, the space of the area should have sufficient space. As mentioned this is also one of the contributors to the 315 kVA Mini substation price. The purpose of finding the right area is for the installation of the mini substations.
Although they are much smaller than regular substations, they can still run into space issues if the land area is small.
The right area is also necessary for clearances for safety purposes. Furthermore, this helps with the access as well for maintenance for other big electrical devices, such as transformers.
The consumption of space in urban areas can be expensive, but gas-insulated switchgear can help you prevent paying those expenses.
For applications or projects that are near shorelines or beaches, it is most likely that the installation setup will be elevated. This is to keep the electrical device protected against these outside elements.
In addition to the space that is already consumed, the area of designation must have extra room as well. This is primarily for expansion purposes because of the load growth of the mini substation.
Mini substations are commonly centered or aligned to the distribution area as well for fast distribution.
Normally, if the mini substation is in a public place, they are fenced and safely distanced from passers-by. The purpose of this it keep people away from injuries caused by electrocutions.
This is also to keep the electrical system from misoperation and disturbances.
There are cases that installations will not proceed due to improper planning between the consumer and manufacturer, which is why planning should be the first step in the process of purchasing a substation or mini substation.
The layout should be in a one-line diagram form, which means it is the simplified form of switching. In addition to that, it protects the arrangement as well. Including the incoming supply or distribution lines and outgoing feeders.
Electrical companies follow this protocol for the preparation of one-line diagrams, along with the principal elements such as lines, transformers, fuses, circuit breakers, etc.
These are arranged on the page similarly to the formation of other electrical devices.
Usually, incoming lines consist of a disconnect switch and a circuit breaker. There are some cases that some lines that will not have any of both.
The purpose of disconnect switches is to isolate since it does not have the ability to interrupt load currents automatically.
These can be used as a protective device to stop fault currents, and they can be used to switch loads as well.
On top of that, it can cut off a line when power is passing is going in the wrong direction.
When there is a large fault current passing through the circuit breaker, this will be easily detected with the use of current transformers, which are transformers that are specifically made for that.
The magnitude of the current transformer output will be used to activate the circuit breaker, the result of this will disconnect the load supplied by the circuit breaker from its feeding point.
This isolates the fault point from the rest of the system and enables the rest of the system to operate with only minimal impact. These two switches and circuit breakers can be operated in the mini substation, or from a supervisory control center.
Overhead transmission lines, and propagation of lightning and switching surges might result in insulation failures to the mini substation, which is critical damage to the electrical device.
Line entrance surge arrestors are commonly used to protect substations from this type of damaging element.
Once it passes the switching components, the lines will then be given a voltage connection to the buses, and this can be one or more.
These are common sets of busbars that are normally in three since the universal electrical power distribution use for this application are three-phase distribution electrical devices.
The consumption of the switches, buses and circuit breakers will affect the cost and reliability of the mini substation.
Substations and substations also make use of various buses such as double bus, and ring buses. The failure of a circuit breaker does not disturb the power of other circuits.
Parts of the substation can be de-energized for maintenance and repairs.
Mini substations feeding a single industrial load can have fewer switching provisions, especially for installations that only require a little amount of time and effort.
Having buses that are prepared to meet various voltage levels. For transformers, they can be connected between voltage levels as well.
Normally, the setup will have a circuit breaker, and transmission lines. This is for safety purposes if ever a transformer encounters a fault or a short circuit.
Substations or mini substations always have a control circuit to operate various breakers to open. This is in the case when a component fails.
Back in the early days of the development of substations and mini substations, they required manual adjustments and collection of data for load, energy consumption, and unexpected fluctuations.
As time went on, the complexity of distribution networks also grew. This became economically necessary to automate supervision and better control of the substation from an attended point.
This allows improved coordination in the event that there is an accident
There are mini substations that use communication wires for this.
There are different kinds of cables that can be applied to the Supervisory Control and Data Acquisition (SCADA) for substations. For instance, Fiber optic cables are compatible, as well as power-line carriers, and microwave radios.
Unlike before, standardized communication protocols are utilized to get multiple electronic devices to connect or communicate with each other, including supervisory control centers.
Distributed automatic controls at mini substations are one of the factors of smart grids.
The electrical devices that are in and around mini substations can be interconnected by air-insulated bare conductors that are connected to support structures.
The air space that is needed increases together with system voltage and with the lightning surge voltage rating as well.
Mini distribution substations are commonly associated with switchgear that is metal-enclosed. There are no live conductors exposed for this as well.
In terms of high-voltage applications, gas-insulated switch gears are used to reduce to use the space that is required around live buses.
Instead of bare conductors, buses are constructed into tubular containers that are filled with sulfur hexafluoride.
This gas has a higher insulating value compared to air, which allows the dimensions of the equipment to be reduced.
The apparatus can also make use of other insulation materials like mineral oil or transformer oil, paper, polymer insulators, etc.
Most mini substations have a lower price compared to regular substations, including the 315 kVA mini substation price. But factors like location, installation, and specifications will be a heavy contributor to the price.
315 kVA mini substations are commonly designed with steel enclosure housing. Somewhat looking like a container that you regularly see on docks, airports, etc.
The steel enclosure housing protects the components inside, such as the MV ring main switch, step-down transformer, and a voltage distribution compartment.
The step-down transformer voltage’s usually range from 11,000/420 volts, 22,000/420 volts, or 33, 000/420 volts.
Below are the common specifications of 315 kVA mini substations. If there is something you want to tweak, upgrade, or modify, DAELIM can take care of your personal preferences.
Substations including mini substations are primarily controlled and owned by electrical companies. For other users that own buildings, factories, etc. There is a high chance of them owning one as well.
But focusing on electrical company uses, these substations rely on a control system for the purpose of having it remotely supervised and operated.
Although they are small, mini substations are considered versatile devices that serve different purposes and unique functions.
For electrical companies, they are normally used to step down or decrease high voltage levels to make distribution easier. By distribution, refers to the supply of electricity being delivered to houses and other constructions through their connected distribution lines.
As mentioned, the size and kVA rating of mini substations are significantly lower than of regular substations. In addition to that, they have less in the way of the secondary distribution equipment, which is another heavy contributor to the mini substation’s price.
But for mini substations, it is expected that they will have weaker systems in terms of the protection for their controls.
But still, they still have similar functions as with regular substations, except of the fact that they are smaller with a less kilovolt ampere rating.
Mini substations still consist of power transformers, metering, circuit breakers, etc.
But enough of mini substations, what about substations?
Substations are commonly used as interference between parts of transmissions systems, and distribution grids.
These fenced-off areas step down voltages in transmission lines that are more suitable for distribution grids.
Substations have normally had circuit breakers as well. This keeps the circuit breakers from damaging the distribution system, and they can be used to control the path of the current flow in different directions.
When it comes to voltage fluctuations that are caused by increased loads, they deal with it with filter voltage fluctuations.
For this section, this applies to substations as well. In fact, these types are more popular on substations compared to mini substations.
But mini substation prices are significantly lower, but again this solely depends on the manufacturer,
Substations and mini substations are classified by their functions, mechanisms, and roles.
Below are their common types.
Based on its name alone, the function of this mini substation is to specifically decrease high voltage levels or transmission levels to distribution voltages.
Or it can be lowered to what is known as sub-transmission voltages, this is commonly used for industrial purposes.
On the contrary, the output will be directed to a mini distribution substation or a regular distribution substation.
You might have heard of step-down mini substations, this type of mini substation is one of the famous types available in the market.
Step-down mini substations are usually located at different points in an electrical network. They can connect different parts of the network as well that are a source of distribution lines or sub-transmission.
Step-down mini substations have the ability to change transmissions voltages to sub-transmission voltages.
These converted voltage lines can also provide a source for mini distribution substations. There are cases as well that the power is tapped from the transmission line to utilize the industrial capacity.
Mini step-up substations are the complete opposite of step-down transformers, and they are more popular than step-down transformers. So you can expect the price of this mini substation to be higher.
The purpose of this mini-substation is to raise the voltage levels from generators at power plants for electricity to be passed or transmitted smoothly.
Although mini substations are already small, there are just some cases that specific areas that have less space than even mini substations cannot fit in.
One of the best ways to counter this is to install the mini substation underground. This decreases the requirement of space and the small open space above can be used for other construction purposes.
The main purpose of underground distribution mini substations is to provide the best conventional mini substation by not interfering with space above land.
Both substations and mini substations have this version on them, and this type simply refers to mini substations that have wheels on them while containing breakers, bus work, and as well as a transformer.
The bus work is mounted on a semi-trailer that is designed to be pulled by a car or truck.
This type of substation of the mini substation is great for traveling, and it can be used as a backup as well in case of electrical shortages from natural disasters.
Mobile mini substations are also known to have lesser permanent installations, and they can be built in several units as well to meet travel limitations.
The mini substation price for this type is higher than both of the examples above because this substation has the ability to lower sub-transmission voltage. Step-down mini substations may be able to lower voltage levels to sub-transmission levels but only with a limit.
The purpose of this is to supply electricity to the buildings of the area that it is capable of reaching (long distances).
Mini distribution substations are commonly associated with distribution transformers before the power is transferred to the load.
The majority of these electrical devices are commonly located underground.
Just in case you have any confusion about the terms above, below are their definitions.
Transformers are electrical devices that use the working principle of electromagnetic induction to transmit alternating currents, or better known as AC, from circuit to circuit.
This often changes the electric current and voltage.
However, transformers do not pass direct currents or DC. But DC can be used to take out a signal while keeping the part that adjusts the AC voltage.
Transformers can be considered as the key to changing the voltages to lessen energy waste in electrical transmissions.
For transformers, they have the ability to transform voltages of electrical signals from power plants by stepping up or increasing the voltage. But transformers are definitely not limited to that as they can decrease or step down voltages in substations and mini substations as well.
Electrical transmissions are one of the processes of transferring generated electricity to the distribution grid that is found in rural areas.
Transformers play a vital role in this process because they are primarily used to increase voltage levels. The purpose of this is to smoothly deliver electricity to buildings at long distances.
There is also an electrical transmission system that is associated with power plants, along with the distribution systems and mini substations to arrange an electrical grid.
The electrical grid is considered as society’s electricity standard.
Power plants are usually located can be located in remote areas or densely populated areas.
As mentioned, the electrical grid is considered as society’s electricity standard, but there is more to it.
They are specifically designed to provide electricity from generation to customers for normal usage.
These have been continuously modified as well from a small design to now capable of stretching to thousands of kilometers. This connects a lot of houses and other buildings effectively.
The electrical is composed of a lot of interconnections but most of them usually have three main sections which are transmission, distribution, and electricity generation.
This is actually the final step for distributing electricity to homes and other buildings.
To begin with, the distribution grid’s substation or mini substation must be stepped-down first for safety purposes.
Wires will lead off from the near power lines and connect to individual buildings such as houses, apartments, villages, etc. But first, this goes through an electric meter to measure to see how much a certain building consumes electricity.
The electricity will pass through a service panel, this is the panel in which circuit breakers and fuses can be found. The service panel contains all the wires that run to different electrical appliances – All homes are connected to a circuit breaker or fuse.
In this section, you will find the factors that are the major contributors to a mini substation’s price.
As mentioned in one of the sections above, the price of the mini substation will also depend on what type of mini substation it is.
There are specific substations that are more expensive than others due to their function. For instance, mini distribution substations are more versatile compared to regular step-down mini substations and step-up transformers.
When it comes to the brand or company, the more popular it is, the more reliable they are. So, you can expect their prices to be significantly higher compared to mini substations that have no brand at all that are low-quality.
Speaking of quality, there are high-quality and low-quality mini substations out there in the market. Of course, low-quality ones have a lower rate, in exchange for bad quality and weak sustainability, which only leads to expensive maintenance that can probably cost you more.
Whereas high-quality mini substations have excellent sustainability and less maintenance. They are also safer because low-quality mini substations can be of great hazards due to their unknown build and design.
Installation is also a major contributor to the price because the company will have to make time to install the mini substation, and this could range from hours to days, which means the company will put in a lot of effort in installation.
This is why installation costs can be high.
Indoor mini substations are generally mini substations that can be used or place indoors. This substation has low voltage requirements inside establishments.
Outdoor mini substations are mini substations that are specifically for outdoor purposes only, this type of mini substation is usually protected in a metal fence or enclosure to avoid outside elements from disturbing its operation.
They are known to be easy to repair compared to indoor mini substations. However, due to their exposure outside, a lot of protection should be added in order to secure it from outside elements such as natural disasters, lightning, debris, animals, etc.
This leads to the cost expenses, you can expect that you will have to spend more money on outdoor mini substations for added protection since they are exposed outside.
But since outdoor mini substations are expected to take a beating from outside elements, markets have made their parts widely avaible. So, you dont have to worry about finding their parts from different countries or places.
On the contrary, outdoor mini substations are the substations that are installed for high voltage requirements outside buildings or establishments.
Indoor mini substations are substations that can be placed inside buildings or establishments without any danger because for one – it passes the fire code of most buildings. They are easier to maintain as well since they are inside buildings.
However, they do require regular maintenance due to their components – even if they are safely secure inside buildings.
There are several elements that indoor mini substations are better at, and there are elements the favor outdoor substations.
For instance, when it comes to fault clearing, this process is much easierer to do in indoor mini substations than outdoor mini substations.
Substations and mini substations normally consist of switching, control equipment, and transformers.
For large substations, usually have circuit breakers to disrupt short circuits or overload currents. These sometimes happen on the network which is why circuit breakers play a vital role in substations and mini substations.
Mini distribution substations also use recloser circuit breakers to protect the distribution circuits. This can be done with fuses as well.
Substations and mini substations do not usually have any generators with them, but the majority of power plants have substations or mini substations near them.
Other electrical devices are also associated with mini substations that may be located in the vicinity such as voltage regulators, reactors, capacitors, etc.
There are mini substations that can be located underground and on the surface as well. For surface mini substations, they are usually enclosed with cages or enclosures to prevent outside elements from disrupting their operation.
Some mini substations can also be placed inside buildings. In fact, high-rise buildings may consist of several indoor mini substations.
These types of mini substations are usually located in urban areas to mitigate the noise from the transformers because depending on what type of transformer it is, it can be very noisy and unpleasant to hear to the public.
An earthing system is necessary for accurate calculations to protect passers-by in the event that there is a short circuit in the transmission system. Ground faults at mini substations can cause a ground potential to rise.
Currents that are flowing in the ground during a fault can result in metal objects with new voltage levels than the ground under someone’s feet.
This touch potential will present a hazard of electrocution. This is why metallic fences should be properly grounded to protect people from this dangerous occurrence.
There are several mini substations and regular substations out there in the market that can be above-ground. This includes metal towers, tubular metal structures, and a utility pole.
There are other variants available as well.
However, this build requires more space in return for low-cost supports for the transmission lines and apparatuses. Some substations and mini substations are kept in suburban areas if appearance is one of the factors for the purchase decision.
Indoor mini substations may or may not have gas-insulated switchgear (depending on what you prefer). For lower voltages, the switchgear will be metal-enclosed.
Substations and mini substations in urban and suburban areas are usually constructed outside to blend in with their environment.
A small substation is good for outdoor applications, and they are typically covered with a metal enclosure to keep the passers-by away from the electrical devices. Each electrical device can be close to one another for smaller footprint size reasons.
Indoor mini substations are known to have a complex construction while outdoor mini substations have a less complicated build and design.
This is because there are added protective parts and layers to indoor mini substations for maximum protection and security for indoor usage.
Indoor mini substations can install up to 66kV voltage levels while outdoor mini substations can install 66kV voltage levels and more.
So, outdoor mini substations have a higher reach in terms of voltages.
Based on the names that they are given, indoor mini substations are specifically for indoor use only, and outdoor mini substations should only be operated outdoors.
When it comes to the selection of its area, mini substations can easily fit in smaller spaces compared to its bigger regular version.
However, there are still specifications that need to be met in order for it safely operate.
For instance, sufficient land area is vital for the installation process of the mini substation. There should be a path or way as well for large electrical devices like transformers.
Gas-insulated switchgear greatly helps you when it comes to saving money. Mini substations that are located in coastal areas ate usually affected by floods and other natural disasters that are associated with strong winds, rain, etc.
This means that they require an elevated structure to keep the device from malfunctioning against these elements. The area of the mini substation must also have room for expansion, this is because of load growth or transmission additions.
Environmental effects should be considered as well because of disrupting elements like a flood, debris, etc. Can have a drastic effect on the mini substation.
It is important that the area of the mini substation must be reasonably centered to the area of distribution as well to be served.
The site must be placed with hazards and barriers as well to avoid people from coming in. Injuries from electrical shock or arcs can be highly dangerous and life-threatening, which is why placing barriers around the area is highly recommended.
When it comes to space consumption, both may be mini substations but outdoor mini substations are slightly bulkier than indoor mini substations. But nonetheless, they are pretty average-sized mini substations compared to their bigger version which is the normal substation.
Both types can expand their installations. However, indoor mini substations are difficult to expand installation. Whereas, outdoor mini substations are much easier to expand their installation.
The cost of indoor mini substations is significantly lower than outdoor mini substations. This is because you have to add protection to outdoor mini substations since they are exposed outside where rain, natural disasters, and other phenomenons can damage the mini substation.
Fault clearing can be very hassle, but indoor mini substations, are very easy to clear. On the other hand, outdoor mini substations can be very hard to deal with in terms of clearing their faults.
Despite that indoor mini substations are safely settled inside buildings, they do require regular monitoring or maintenance. In fact, they are actually considered a high-maintenance electrical device.
For outdoor mini substations, they may be exposed to outside elements but their structure makes them durable enough for less maintenance.
Aside from the monitoring, you will have to look into the replacements and repairing as well. Indoor mini substations are harder to repair and replace compared to outdoor mini substations. Sometimes, parts are not widely available as well.
Of course, indoor mini substations require less protection since they are safely settled in buildings, but outdoor mini substations require a lot of protection.
Almost anything can be considered as an enemy to outdoor mini substations. Dust, debris, lightning, animals, you name it. But there can be several ways to prevent outside disruptions, such as by adding a cage or protective shield around the outdoor mini substation.
One of the reasons why indoor mini substations can be placed inside buildings is because they pass the fire code of most buildings, whereas outdoor mini substations are considered dangerous to be placed near buildings.
They are simply not suitable and compatible for this exposure.
For outdoor mini substation structures, they usually include wood poles, metal structures, and lattice metal towers. But depending on the variant, this could vary.
Steel lattice towers give low-cost support for transmission lines. For low-profile mini substations, they can be classified in suburban areas wherein the appearance weighs more.
Indoor mini substations can be gas-insulated switchgear at high voltages or metal-enclosed at low voltages.
Both urban and suburban mini indoor substations may be finished externally to blend with their surroundings.
The majority of compact substations are usually outdoor substations that are built in a metal cage or enclosure. In this setting, each item is significantly closer to the other, which creates a smaller footprint size of the substation.
The first thing to do when it comes to planning a substation or mini substation layout is the preparation of a one-line diagram. This shows the simplified form of switching and protection of the arrangement required.
In addition to that, this includes the incoming supply lines and outdoing fees or transmission lines.
Electrical utilities normally practice this to prepare one-line diagrams with the lines, circuit breakers, switches, breakers, and transformers that are arranged on the page. that is similar to the way apparatuses should be laid out in a mini substation.
Following the common design, incoming lines usually have a disconnect switch and as well as a circuit breaker. There are even times that the lines will not have both.
The function of the disconnect switch is to give isolation since it cannot interrupt the load current.
For the circuit breaker, it is a device that is used for protection, to interrupt fault currents automatically. They can be used to turn on and off switch loads of a line just in case power is flowing in the wrong path.
In the event that a large fault current passes through the circuit breaker, this will be detected by current transformers.
The magnitude of the current transformer outputs can be utilized as a trigger for the circuit breaker, which results in a disconnection of the load that is being supplied to the circuit breaker from the feeding point.
This will isolate the fault point from the rest of the system. Moreover, this allows the rest of the system to continue operating with less impact. Switches and circuit breakers can be both operated locally or remotely.
As mentioned in the introduction, DAELIM has been specializing in mini substations for 15 years and has manufactured hundreds of mini substations for clients around the world. DAELIM’s mini substations promote efficient use, sustainability, versatility, and convenience.
DAELIM offers different types of transformers with indoor and outdoor variants for your convenience. Along with fair quotes, DAELIM is known to have excellent customer service before, during, and even after deals.
For inquiries, questions, or concerns, you may contact DAELIM’s team of professionals.
Substations and mini substations have different prices, and depending on the manufacturer’s quote, mini substations can be more expensive than regular substations. There are a lot of factors to consider for the right quote.
But to get the best out of your money, make sure to only make business with reliable manufacturers that offer fair quotes with excellent customer services.
Mini substations are great for applications that have less space, they are just as efficient as regular substations but they do lack in size and kVA rating.
Regardless, they have different types as well so you can choose whichever fits your purpose, whether indoor or outdoors.
Should you have further questions or concerns, you may contact DAELIM for fast accommodation.
ELECTRIC, WITH AN ENGE-- DAELIM BELEFIC