There are countless Residential pad-mounted transformer types out there that exist with different functions. In terms of size, shape, design, build, and other features, it has its unique attributes as well.
But in this article, DAELIM, one of the top electrical companies in the world, will educate you on everything you need to know about one of the most common transformers today, which is the Residential pad-mounted transformer.
But first, how does a transformer work and what is it? The answer to these questions will help you digest the information that will be presented to you as we go deeper into this article.
Transformers are electrical devices that are capable of doing much work. Basically, it is a versatile electrical device that is commonly used in electrical companies to provide electricity. Furthermore, there are several kinds of transformers out there that is not only limited to such feature.
Transformers are capable of many operations including transferring electric energy from one alternating circuit to other circuits and this can be transferred to one or more circuits. This is done by increasing or reducing the voltage levels. This is also known as “stepping up” and “stepping down”.
As aforementioned, transformers are capable of doing many and different operations, which makes you question – how does it work?
Transformers can reduce conventional power circuits for the purpose of using low-voltage devices. This could be as simple as an iron, speakers, TV, and many more. Furthermore, transformers can be used to raise electric generators for electricity to be transmitted even in long distances.
When it comes to the scientific explanation of how transformers work, they work or change voltage under the influence of electromagnetic induction. For instance, as flux lines or magnetic lines build and collapse with changes in the current that is passing the primary coil, you can expect the current to be induced in another coil, which is the secondary one.
Let’s take air-core transformers as an example, they are specifically made to transfer radio-frequency currents like currents that are used for radio transmissions and they primarily consist of two coils, and it can also be more than one, and they are around in a solid insulating substance or an insulating coil form.
On the other hand, iron-core transformers serve analogous purposes in the audio-frequency range aspect.
Other kinds of transformers have similar working principles as well but have unique attributes.
Residential pad-mounted transformers are basically ground-mounted transformers that are specifically designed to supply electricity to multiple houses. Moreover, they are distribution transformers that are locked in a steel cabinet that is mounted on a concrete pad.
Pad-mounted transformers can usually be found in public, but they are not as common as pole transformers. Pole transformers are basically those barrel-looking electrical devices that you see on utility poles in the streets.
For starters, they do not have the same function as pad-mounted transformers. In fact, pad-mounted transformer specifications alone are already very different. The same goes for the size and appearance as well.
Pad-mounted transformers are basically transformers that sit on a pad that looks somewhat like a wide metal cabinet or locker. Overall, their appearance is nothing alike compared to power transformers and distribution transformers.
The pad-mounted transformer is a compact, complete set of power distribution devices composed of high-voltage, power transformers, low-voltage, and electric energy metering devices combined in one or several boxes. Compared with traditional substations, it has. It has the advantages of flexible combination form, short construction period, low operating cost, and small footprint. It is manufactured in a factory and does not require complicated on-site installation.
Therefore, Pad mounted transformer is widely used in the power supply system of residential quarters.
This type of transformer is commonly called either a padmount or pad-mounted transformer, which once again, is basically a ground-mounted electric power distribution transformer that looks like a wide metal cabinet since it is locked in a grounded metal housing.
Residential pad-mounted transformers are suitable for places that do not have the luxury of space, wherein a fenced enclosure is required. They are commonly used with underground distribution lines as well that are specifically located at service drops for the purpose of stepping down the primary voltage that is inlined with the lower secondary voltage that is supplied to utility customers.
Although they are called Residential pad-mounted transformers, this does not mean that they are only made for providing electricity to several homes, because this type of transformer will do fine in providing electricity to one house only.
Residential pad-mounted transformers have power ratings that range from 15 to 5000-kilovolt amperes, and this also depends if you have a single-phase pad-mounted transformer or a three-phase pad-mounted transformer.
But the majority of pad-mounted transformers have elbow connectors that are operated if they are only energized. This can be done if there is a hot stick, which allows convenience when it comes to regular maintenance.
Single-phase pad-mounted transformers are exceptional Residential pad-mounted transformers that are usually rated between 10-220 kVA that are designed to be compatible with various applications, which means that even though they are single-phase pad-mounted transformers, they still meet A.N.S.I and N.E.M.A standards,
Single-phase pad-mounted transformers may be filled with mineral oil or better known as transformer oil, and even fire-resistant environment FR3 fluid.
Take this DAELIM Single-phase Pad-mounted Distribution transformer as an example:
All transformers from DAELIM are expertly crafted for security purposes and the best experience for the customers. When it comes to the DAELIM Single-phase Pad-mounted Transformer, it is far from the performance of generic or unbranded single-phase pad-mounted transformers.
DAELIM has made this electrical device with the necessary upgrades in order to satisfy the user’s needs such as friendly price, the right size, versatility, longevity, enhanced kV rating, and many more attributes that are upgraded.
If ever you do not have a distribution room to place it indoors, the DAELIM single-phase pad-mounted transformer can be placed indoors. So, if space is a problem, then you won’t have to worry about that with this transformer.
However, if you are planning on using it indoors, make sure that it passes the fire code of the building you are using it in since this transformer contains oil that is highly flammable. When it comes to placing it outdoors, there will be no problems with that also.
single-phase pad-mounted transformers have green belts with them for safety purposes. The green belt helps protect the public in the event that there is a malfunction in the single-phase pad-mounted transformer.
Overall, the DAELIM single-phase pad-mounted transformer is a great electrical device that can be shipped in whatever enclosure you may want it to be in. In terms of shipping, DAELIM offers both water and air shipment of all locations for your convenience. There is an abroad team that is ready to assist you as well.
But what about three-phase pad-mounted transformers? Are they any better?
On the other hand, when it comes to three-phase pad-mounted transformers, they are still compact power centers that are commonly used for industrial applications, commercials, and other utilities. They are also designed to be durable in order to sustain itself against harsh environments since it is exposed outside.
You can find three-phase pad-mounted transformers inside and outside buildings for the purpose of energy efficiency and safety precautions.
Since three-phase pad-mounted transformers are considered fluid-filled transformers or electrical devices, they have a wide variety of configurations which means that they can be paired with many accessories for an upgrade or to meet the necessary specifications.
For starters, three-phase pad-mounted transformers start operating when a primary voltage goes in the cable that is specifically designed to resist high voltages. The voltage will then be passed to the H1-A bushing then onto the transformer’s windings to the side of the Z bars.
After passing through the side of the Z bars, the voltage will then go through the connection points that exits the cable for it to go through its final destination. In terms of electrical distribution to houses, this will serve in the range of 220V to 240V.
It is not common for pad-mounted transformer connections to come in many numbers. In fact, this is common among loop-fed pad-mounted transformers. The reason why it has many terminals is for it to be powered by two medium-voltage circuits.
Just like typical distribution transformers, these transformers are always loaded with mineral oil, which is why it is commonly found in public areas since mineral oil does not pass the fire codes of most buildings.
In terms of their core and coils, they are sheltered in a tank that is oil-filled and made out of steel with terminals for the Residential pad-mounted transformer to be made accessible in an adjacent lockable wiring cabinet setting.
It is also expected that the wiring cabinet has both high and low voltage wiring compartments for versatility.
Normally, Residential pad-mounted transformers weigh about 800lbs which is why when installing or replacing a pad-mounted transformer requires a truck with a hook in order to lift the transformer and put it into its place.
Transformers themselves are known to last very long due to their strong build and design from material to the main structure of the transformer.
Residential pad-mounted transformers have an expected life span of more than 30 years. In fact, even Residential pad-mounted transformers are still operating for more than 50 years! This means that when it comes to their longevity, you won’t have to worry about them wearing out any time soon.
In terms of passing by or standing near a Residential pad-mounted transformer, it is completely safe since there are no scientific pieces of evidence that standing near a transformer will pose an electrical health risk to you unless you accidentally bump into one.
However, for the security of pedestrians, Residential pad-mounted transformers should always be closed and locked with warning signs all over their metal enclosure. The installers will make sure there is at least 10 feet of clearance at its opening side to avoid disruption and easy access to the transformer.
A space of 5 feet for the sides will allow the space to maneuver in the case that a dangerous phenomenon occurs.
Residential pad-mounted switchgear is specifically designed to meet the requirements of the switching and isolating features of the electrical distribution system, and this goes along with 15 pre-engineered switching configurations.
Similar to the question of Residential pad-mounted transformers, they are not if not disturbed by outside elements. However, when it comes to the device catching fire that leads to an explosion, it is possible.
This could also happen for various reasons such as lightning strikes, an animal tampering with the transformer, water getting in the windings, and many more.
These are rare instances but Residential pad-mounted transformers are equipped with safety fuses as well to mitigate the damage.
The box part adopts the current domestic leading technology and technology; the outer shell is generally made of galvanized steel plate, the frame adopts standard container materials and production technology, has good anti-corrosion performance, and guarantees no rust for 20 years. The inner sealing plate adopts an aluminum alloy gusset plate, and the interlayer adopts Fire insulation material.
The temperature adjustment and dehumidification device are installed in the box, and the operation of the equipment is not affected by climatic conditions and external pollution. It can ensure regular operation in a harsh environment of -40 ~ 40 ℃. The primary equipment in the box adopts domestic technology-leading equipment such as a unit vacuum switch cabinet, dry-type transformer, dry-type transformer, vacuum circuit breaker (spring operating mechanism), etc. The product has no exposed live parts and is a fully insulated structure that can achieve zero electric shocks. In an accident, the entire station can be operated without oil, with high safety. The secondary equipment adopts a computer-integrated automation system, which can realize unattended operation.
Pad mounted transformer adopts the module method in structure, and each Pad mounted transformer can be composed of the following types.
The type of high-voltage switch connected to the power grid is divided into ring network type, dual power supply type, and terminal type;
According to the type of built-in transformer, it is divided into oil-immersed fully sealed transformer and dry-type transformer; according to the material of the box shell, it is divided into the metal shell and non-metal shell type;
According to the selection of high-voltage switch, it is divided into gas-producing load switch, compressed air load switch, vacuum load switch, and SF6 load switch; according to whether the intelligent system can be configured, it is divided into intellectual type of compact type.
Usually, the high-voltage room, transformer room, and low-voltage room are distributed before and after, and the structure is compact, which is convenient for installation, site selection, operation, and inspection.
It is especially advantageous when multiple transformers are arranged in the transformer room.
The box shell is made of galvanized steel plate and container manufacturing technology, and the appearance design is beautiful, under the premise of ensuring the reliability of the power supply.
By choosing the shell color of the Pad mounted transformer, it is easy to coordinate with the surrounding environment.
Used in densely populated areas such as urban residential quarters, it can be used as both a fixed substation and a mobile substation, which not only does not affect the coordination and beautification of the environment but also has the effect of embellishing and beautifying the environment.
According to the power supply requirements of different communities, it can be used for the ring network and the terminal. The conversion is convenient, which significantly improves the reliability of the power supply, and the impact of a single equipment failure is small; a single-phase Pad-mounted transformer does not need to be up-rod during troubleshooting or replacement. Or work on the bench, the weight is much lighter than the three-phase Pad-mounted transformer, and it does not require the cooperation of large construction equipment, so the maintenance or replacement is more convenient and quick, and the repair time can be significantly shortened.
The pad-mounted transformer is divided into European-style Pad-mounted transformers and American-style Pad-mounted transformers according to the structure. The European-style Pad-mounted transformer is flexible in design; that is, the transformer and high and low voltage switchgear are divided into a high voltage room, transformer room, and standard voltage room, which are combined in one shell, One or more transformers can be placed in a Pad-mounted transformer, and users can freely choose high and low voltage components, cabinet types, and transformer models.
If the equipment fails, it is easy to replace, but the volume is too large, the heat dissipation is complex, and the price is high. The American Pad-mounted transformer is mainly based on the transformer. The load switch and fuse are installed in the oil tank of the transformer to form an integrated arrangement. The volume is only one-third of the European Pad-mounted transformer of the same capacity, and the price is only half of the European Pad-mounted transformer.
Since the oil tank of the transformer is part of the housing of the Pad-mounted transformer, the heat dissipation conditions are good. After a comprehensive comparison of technology and economy, a Pad-mounted transformer is preferred in urban network reconstruction. The choice of the capacity of the Pad-mounted transformer significantly influences the overall investment benefit.
The compact design of the Padmount transformer requires a high degree of integration in the automation design of the device to realize functions such as communication, fault detection, remote control, telemetry, remote signaling, and reactive power compensation. It needs to adopt an intelligent system integrating protection and monitoring. The implementation of the distribution automation system is organically incorporated into the distribution automation system.
The basic configuration includes:
(1) The current accuracy of the AC sampling of the analog data acquisition and processing device should be at least level 1.0.
(2) Fault indication function A fault indicator with signal output is installed on the side of the 10kV incoming and outgoing lines, and the signal is uploaded to the communication unit. The power supply and distribution dispatching center analyze the fault point.
(3) The digital quantity acquisition and processing device should be able to collect the required digital quantity and have the signal hold function for the instantaneous signal generated by the fault indicator, as well as the self-recovery process.
(4) Communication function: It uses GPRS or CDMA wireless communication technology to communicate with the dispatch center and transmits telemetry and remote signaling.
(5) The reactive power compensation function automatically switches the capacitor according to the voltage and reactive power relationship.
According to the requirements of the reliability of power supply in different residential areas and other needs of customers, there are the following single-phase Pad-mounted transformer power supply methods to choose from.
(1) The power distribution station or outdoor ring network cabinet, high-voltage cable branch box, and ring network type single-phase Pad-mounted transformer form a chain power supply mode.
The advantage of this power supply method is that each single-phase Pad-mounted transformer has two power supplies, and the power supply reliability is high;
But the disadvantage is that the length of the high-voltage cable is long, the investment is slightly higher, the operation mode is somewhat complicated, and the interlocking problem between the two power sources needs to be solved.
The power supply mode of this single-phase Pad-mounted transformer is suitable for the single-phase Pad-mounted transformer to supply power to users with dual-circuit power supply requirements.
For example, in a residential area, the high-voltage power supply line is single-phase and is connected to the A, B phase, B, C phase, C, and A phase through two single-core cables or two-core cables. The Pad-mounted transformer uses two T Type bushing + elbow-type cable plug for ring supply connection, play the role of four-way, respectively connect to the incoming line, loop line, outgoing line, arrester position, and install a two-position low-voltage load switch at the outgoing line position to connect or Cut off the load carried by this single-phase Pad-mounted transformer or replace the two-position load switch with an elbow-type cable plug and double fuse protection. Plug and unplug directly.
(2) The power distribution station or the ring network cabinet, the high-voltage cable branch box, and the ring network type or terminal type single-phase Pad-mounted transformer with a two-position low-voltage load switch form a trunk-type power supply mode.
The characteristic of this power supply mode is that the power distribution station or the ring network cabinet outputs a single-channel power supply to the high-voltage cable branch box. The incoming line is a three-phase type, and the outgoing line is a single-phase type. In A, B, B, C, C, and A phases, the outgoing circuit is controlled within six circuits, and each circuit does not exceed 3 single-phase Pad-mounted transformers. The total number of single-phase Pad-mounted transformers carried by each branch box is. The number of units shall not exceed 18 units.
The first two single-phase Pad-mounted transformers in each outgoing line are ring network type, and the last one is terminal type.
The advantage of this method is that it can be connected in series with three Pad-mounted transformers that are closest to the actual distance on-site, saving the investment of high-voltage cables; the disadvantage is that there is only one power supply, and the power supply reliability is lower than that of the chain power supply method. Power users.
(3) The power distribution station, outdoor ring network cabinet, and ring network type or terminal type single-phase Pad-mounted transformer with double fuse protection (no-load switch) form a radial power supply mode.
The characteristic of this power supply mode is that the power distribution station outputs one primary and one backup two-way power supply to the outdoor ring central unit, and then the outdoor ring main unit (not the high-voltage cable branch box) goes out to the single-phase Pad-mounted transformer. The cable is expanded into double cable terminals (two A-phase, B-phase, C-slot respectively), divided into three single-phase outgoing lines (A, B-phase, B, C-phase, C, A-phase respectively), each outgoing line. The first two in the middle are single-phase Pad-mounted transformers of ring network type, and the last one is terminal type, with no more than three transformers per circuit.
The advantage of this method is that it can be connected in series with three Pad-mounted transformers that are closest to the actual distance on-site, saving the investment of high-voltage cables; at the same time, because the external ring network cabinet has a two-way power supply, it has both the chain mentioned above type and trunk type. The advantages of the two power supply methods: the reliability of power supply is higher than that of the trunk-type power supply method, and the investment is lower than that of the chain-type power supply method; This method is most suitable for residential quarters with multi-story buildings as the mainstay: such as residential areas developed and constructed in townships, demolition and resettlement areas, etc.
There is without a doubt that Residential pad-mounted transformers are essential to the community. This is the main reason why DAELIM manufactured several variants of Residential pad-mounted transformers.
If you are looking for a transformer that is easy to operate, compact, durable, and with excellent longevity then a Residential pad-mounted transformer is a great choice for you. Whether it is for multiple houses or only one, this pad-mounted transformer will perform outstandingly.
If you have any questions or clarifications, do not hesitate to contact DAELIM’s team of professionals for immediate assistance.
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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