Knowing More on A Pad Transformer
| Table of contents |
| 1. What is the pad type transformer? 2. What does a pad-mounted transformer do? 3. What is protection for pad mount transformer? 4. What is the color of the pad-mounted transformer? |
What is the pad-type transformer?
The pad-type transformer here can be understood as generally speaking, it usually refers to the special and specific shape and type of shell type that some medium and small transformers have.
These transformers are installed in outdoor places that the general public can see. Or at the door of every household. These pad-mounted transformers with enclosures have the following special features: It contains a special design structure, including especially required screws, nuts, and bolts. These will all be tamper-proof designs.
At the same time, the high and low-pressure chambers of high and low pressure are equipped with hinged doors and high and low-pressure compartments.
As well as entry to the bottom cable air compartment for the primary, or special case vents, which may have baffles here. These special properties are fundamentally different from ordinary transformers and also separate their characteristics. very representative.
The rated power of the pad-mounted transformer is usually 75KVA-7500KVA, and generally, it will be required to be equipped with a fuse and an on-load tap-changer.
Learn more: 3 Phase Pad Mounted Transformer-Daelim Belefic
So what's inside the very iconic welded enclosure?
The casing or what we call the tank contains mineral or vegetable oil, along with some iron cores and winding coils that are soaked in oil. As well as divided high and low-voltage chambers, bushings, intrusive fuses, etc. These are designed to be tamper-proof and usually have an immovable cover welded to the top of the tank. However, the design of our DAELIM is a bolt type, which is for the convenience of subsequent maintenance and repair, and reduces the operating cost of the pad-mounted transformer under the condition of ensuring safe use.
We can understand that this bolted design is a shielded design. Usually, it will protrude a few inches from the top cover of the fuel tank. At the same time, it can also be waterproof and anti-corrosion. Water droplets will flow out along the edge of the cover.
At the same time, we can also see that the front end of the shell is designed as a typical wiring cabinet, and its left and right sides are designed as lockable cabinet doors that can move left and right. When closed, the right side moves in the opposite direction. Or both sides open outwards and close inwards at the same time.
Another point is that it is recommended that the installation power company refer to the actual installation location. These are based on the insurance industry's assessment of comprehensive safety requirements to keep buildings safe and prevent fires.
These installation companies can negotiate with the owner and the construction company insurance company to finally give the design size and scheme of a suitable and safe pad-mounted transformer.
What does a pad-mounted transformer do?
In our daily life, you may notice these green or black boxes on the side of the road, the corner of the road, and the backyard of the house behind the building. They are pad transformers and play an important role in the electricity use in our daily life.
We can next describe how some pad transformers work. Mainly divided into single-phase and three-phase.
Single-phase pad-mounted transformers: Generally, the green shape is small, and the capacity is from 15KVA to 250KVA or more.
The inside is the medium and high voltage from the substation, that is, the voltage level of the utility is reduced to 240/120V, which is a very common residential household voltage.
Generally, it is output from the secondary end of the transformer, through the underground cable, and output to each household. At the same time, it is not only used for residential electricity but also supplies power to other small devices around community houses, such as traffic lights, street lights, store signs, and other devices that consume less electricity and load less.
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The other is the three-phase hanging transformer: in terms of appearance, the three-phase transformer will be applied in a larger green or gray metal casing.
Generally, the initial voltage will be 12.94KV, 13.8KV, 34.94KV, 27.6KV, etc. Then reduce to the commonly used voltage such as 120/240V, 277/480V, and 120/208V. Then it is directly supplied to the customer, and then the owner installs the secondary cable, and the secondary voltage of the transformer is input into the building through the underground equipment. Or large-scale electricity-consuming places such as shopping malls and stadiums that consume a large amount of electricity.
At the same time, whether it is three-phase or single-phase pad-mounted transformer, attention should be paid to the aesthetics of the surrounding environment during installation to ensure that inspectors can check and visit at any time.
Learn more about pad transformer: 2500 kVA Pad Mounted Transformer
What is protection for pad mount transformer?
We can study and introduce the underground power transmission and distribution system
For example, there is a three-phase pad transformer here, 1000 kVA, 13.8kv/120-208V, and there will be 2 types of protection fuses protection.
BAYO NET fuse can be considered to use ABB brand 200A, of course, the selection is based on the actual transformer parameters.
CL FUSE can consider using COOPER's 200A, of course, the selection is based on the actual transformer parameters.
The fuses here can also set the switchgear.
Much depends on your basic fuse coordination philosophy. Do you want the circuit breaker in the station to trip and save the fuse? Or do you want the fuse to blow so that the circuit breaker doesn't work?
Here we can consider using a combination of the two.
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A fuse is just a small piece of wire that will melt if the current gets too high. Just a cheap alternative to current-limiting fuses.
The main function of a fuse or CLF is to prevent the transformer from catching fire. If any of these work, it means the transformer is faulty and needs to be replaced anyway.
What is the color of the pad-mounted transformer?
Green Munsell 7GY 3.29/1.5 or ANSI 70 Built to all applicable IEEE C57.12.34.
The following standard is referenced by this specification.
American National Standard for Switchgear and Transformers - Pad-Mounted Equipment
- Enclosure Integrity, ANSI C57.12.28.
All standards referenced by this specification are the latest revision unless otherwise indicated.
Four coupons shall be supplied; two 3 x 6-inch coupons as shown in Figure 1, and two
4 x 4-inch coupons as shown in Figure 2.
Coupons shall be made from the same material, lightest gauge, and processing as used in
production. They shall be cleaned, coated, and cured using the production coating system.
Each coupon shall be stamped with the manufacturer's logo and plant designation code as shown
on Figure 1 and Figure 2. A key to plant codes shall accompany the coupons.
The edges of the coupons shall not be waxed.
The top coat color shall be Munsell GY 3.29/1.5 green unless otherwise specified. Coupons shall be coated on all surfaces.
The paint system used shall meet or exceed the Enclosure Coating System Section of the American
National Standard, ANSI C57.12.28.
The lamps used in the Ultraviolet Accelerated Weathering test shall be UVB-313
fluorescent lamps.
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What is inside a pad-mounted transformer?
It is a kind of transformer that combines high-voltage load switch, plug-in fuse, backup protection fuse, transformer body, and non-excitation switch in a sealed oil tank and uses transformer oil as the insulating medium. The high-voltage circuit and the transformer body of the combined transformer are assembled in the oil tank, and the incoming line and operation of the high-voltage circuit are carried out on the high-voltage side.
The transformer design is basically the same as the ordinary transformer design principle. The iron core material can be made of high magnetic permeability silicon steel sheet or amorphous alloy. The iron core structure can be laminated or wound iron core structure. The winding can be made of copper wire or copper foil.
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High-voltage system and outlet method. The high-voltage system wiring methods include ring network type, terminal type, and terminal double-loop type.
The ring network type is "one in and two out", one power supply line is incoming, one is outgoing from the low-voltage side of the transformer, and the other is led to another transformer or other electrical appliances to provide an application for the low-voltage side of another transformer or other devices source. The terminal type is "one in and one out", one for Shenyuan to speak the line, and one for the outlet from the low-voltage side of the pressure device.
The terminal loop type is "one input, one output, and one backup", one power input line, one output line from the low voltage side of the transformer, and the other is the backup power supply. When the main input power supply fails, the backup power supply is used.
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Customized pad transformer
DAELIM is a professional Pad Transformer Manufacturer, which can design pad transformers according to your requirements and technical parameters. The transformer brand is DAELIM Belefic. DAELIM has 20 years of experience in transformer design and export, and the market involves six major states in the world. The main markets are the United States, Canada, Mexico, Australia, Ecuador, Honduras, Chile, and other North America, South America, and Oceania.
DAELIM Pad Mounted Transformer Project Cases
DAELIM not only has the test reports of transformer products but also has the most authoritative certificates in the industry, such as UL, and CSA. The designed pad transformers fully meet the standards of IEEE/ANSI/DOE/CSA/IEC/AS. The professional transformer technical team and pre-sales service team will make you feel the importance of easy and smooth communication and technical expertise. If you have technical problems or need of pad transformer, the DAELIM team will serve you wholeheartedly.
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