How to Choose Pad Mounted Transformer?

In the construction of engineering projects, the optimal allocation of power resources is the key for the project to meet the start-up requirements.

The pad mounted transformer can realize power modularization in engineering construction, rapid power supply, and its equipment is easy to install and dismantle, which meets the power supply requirements of modern construction sites.

Therefore, it can be seen that the pad mount transformer plays a great role in the construction site of power engineering.

In terms of safety, the transformer enables the construction personnel to avoid the working environment of strong voltage and ensures the construction safety of the construction personnel.

Can you paint pad mounted transformers

Three Phase Pad Mounted Transformer

Rated Power:75~2500 kva No-load Loss:180~2680W On-load Loss:1250~27786W

Single Phase Pad mounted transformer

Rated Power:15~167 kva No-load Loss:50~350W On-load Loss:195~1410W

Table of Contents

When selecting a pad mounted transformer, the power load should be calculated according to the planned construction module, and the capacity of the transformer should be selected according to the corresponding value of the load. For the main contract section, the capacity of the transformer should be increased.

When calculating large-capacity loads, multiple transformers should be used to reduce damage to their wires.

The weight of a single pad mounted transformer should also be controlled. In order to facilitate the deployment and installation during on-site construction, its weight should be controlled within 5 tons to meet the requirements of rapid response.

The grounding resistance of each pad mounted transformer should be less than 4 ohms, and its neutral point and grounding zero line must be well grounded to ensure the safety of electricity use.

application of pad mounted transformer

In order to prevent the phenomenon of partial load in the power supply at the construction site, the cross-sectional area of the neutral line and the neutral line of the transformer should be greater than half of the phase line.

The Padmount Transformer has high requirements on temperature. To control the temperature rise of the transformer, the temperature cannot exceed the temperature specified by the manufacturer.

The shell of the transformer should be made of steel, and its top cover should be easy to disassemble, so as to facilitate the maintenance of the transformer and other related work.

How to Buy a Pad-Mounted Transformer in the USA?

Daelim pad-mounted transformer is a power transformer that complies with IEEE/ANSI/DOE/CSA standards and adopts the latest energy-saving technology. It is available in three-phase and single-phase styles.

They can choose copper or aluminum winding materials. The coil is purchased in a circular layout. The rated power range is: 75~5000 kVA.

Daelim pad-mounted transformer main power cord is linked by elbow connector, built-in fuse and switch settings.

At the same time, Daelim provides at least two years of warranty service for the pad-mounted transformer.

Daelim has professional installation teams in many countries to ensure a smooth and professional installation after your purchase is completed.

Power distribution transformers that are pad-mounted are installed in an underground steel cabinet and placed on a concrete slab.

Due to the secure confinement of all electrified connection points in a grounded metal housing, a padmount transformer can be put in locations that do not allow for a fenced enclosure.

These transformers are used to reduce the primary voltage on a utility line from its higher secondary voltage for customers.

A single transformer may serve a single huge structure or a large number of residences.

Pad-mounted transformers are available in power ratings ranging from 15 to 5000 kVA and frequently contain integrated fuses and switches.

Primary power cables may be linked using elbow connectors that activate when energized with a hot stick, allowing for greater repair and maintenance flexibility.

pad-mounted transformer in usa

Step One: Search for the Best Pad-mounted transformer Supplier

When it comes to purchasing a Pad-Mounted transformer, buyers have various alternatives.

However, with so many intricate components of power distribution to consider, finding one that is completely compatible with your equipment and adheres to the facility’s safety standards is no easy task.

To begin, transformers are devices that are used to transmit electricity and/or rectify voltage from an input line (supply line) to an output line (output).

Pad-Mounted Transformers come in a variety of sizes, features, capacities, and applications.

Daelim three phase pad mounted transformer warehouse

Step Two: Choose the Best Suitable Design

Transformers for pad mounting are available in a variety of electrical and mechanical forms.

Transformers mounted on pads are used in medium-voltage distribution systems up to approximately 35 kV.

Low-voltage windings are specified by the customer and may be single-phase or three-phase.

Due to the fact that pad-mount transformers are almost always oil-filled, they must be mounted outdoors only.

Metal tanks contain the Padmount Transformer’s core and coils, which can be accessed through a locked wiring cabinet next to the tank.

The wiring cabinet is divided into compartments for high and low-voltage wiring.

Underground high and low voltage wires enter the terminal compartments immediately.

The tank’s top is protected by a lid held by a carriage bolt-nut assembly.

On two sides of the wiring cabinet, there are sidewalls with doors that swing inward to reveal the high and low voltage wire compartments.

Pad-mount transformers employ self-protecting fuses that include a bayonet mount fuse in a high voltage compartment and a backup high energy current-limiting fuse in series to guard against secondary faults and Pad Mounted transformer overload.

The field-replaceable bayonet mount fuse protects against secondary faults and Pad-Mounted transformer overload.

Due to the fact that the backup current-limiting fuse activates only during transformer failure, it cannot be field replaced.

Additionally, these Pad-Mounted transformers meet the criteria for standard low voltage fusing.

By utilizing polymeric cable and load break elbows, switching and isolation can be performed in a “dead front” environment, in which all terminations are entirely screened and waterproof.

Transformers with single- and three-phase pad mounting are used in underground industrial and residential power distribution systems where a safe, reliable, and visually pleasing Pad-Mounted transformer design is required.

Due to their enclosed design, pad-mount transformers can be installed in public places without the requirement for protective fences.

Pad-mount transformers are typically positioned on roadway easements in residential areas and service many residences.

There are now small single-phase designs with the Pad-Mounted transformer already installed on the polypad base that allow them to be erected on firm ground, connected and switched on, in contrast to classic pad-mount transformers which are permanently fixed to concrete “pads.”

Step Three: Look for the Best Place To Install

An underground utility distribution Pad-Mounted transformer, known as a padmount transformer, is often housed in a metal cabinet on a small concrete pad.

Typically, these distribution transformers are found in residential developments.

A grounded metal enclosure encasing all active contact points allows this transformer to be located in residential areas without the need for fence, unlike utility substation transformers.

Pad “Service drop” points on utility distribution lines are used to connect mounted transformers that lower the principal voltage on the utility distribution line before it reaches a customer’s home or business.

Numerous pad mounted transformers may serve a single huge structure or a large number of households.

Pad-Mounted Transformers must be installed in accordance with applicable fire codes.

Indoor installations must adhere to the National Electrical Code (NEC®) criteria for enough space and proper overcurrent protection, as stated by the listing body with jurisdiction over the installation.

Unless otherwise indicated, these transformers are designed to operate at elevations up to 3300 feet at an average ambient temperature of 30°C and a maximum ambient temperature of 40°C.

Contact an expert prior to using a conventional Pad-Mounted transformer at higher elevations.

Step Four: Know the Specifications and Technical Information

A typical enclosure consists of a tank for immersing the pad-mounted transformer’s core/coil assembly in oil or the like, and a wire cabinet with high and low voltage wiring compartments for containing the pad mount transformer’s high and low voltage bushings, respectively.

To restrict unauthorized access to the device’s core/coil assembly contained within the enclosure’s tank, the most frequent prior art approach is to weld a cover over the tank’s top.

They are typically available in power levels ranging from 75 to 5000 kVa and frequently contain built-in fuses and switches.

Step Five: Read The Manual

Pad Mounted transformers should be situated in conformity with specified standards regarding exterior building walls.

These recommendations are based on the insurance industry’s recommended practices for the outdoor placement of one of these Pad Mounted transformers.

The building owner and/or tenants’ fire insurance carrier, as well as the local inspection authority, may impose restrictions on the equipment’s closeness to any section of the structure.

It is the Customer’s responsibility to determine the proposed location’s acceptability to authorities other than the Company.

Step Six: Mount the Transformer

A level concrete platform should be used to mount the Pad Mounted transformer.

The pad should be robust enough to withstand the transformer’s weight. The site must be sufficiently prepared to prevent the Padmount Transformer from tilting more than two degrees from vertical.

Internal components may protrude from the oil and/or cables, exerting mechanical strain on the bushings and bushing gaskets, if the tilt is greater than two degrees.

Excessive tilt (more than two degrees) can result in the transformer having a lower dielectric strength than the basic insulation level (BIL) specified on the nameplate.

Reduced BIL can cause an internal dielectric breakdown, increasing the likelihood of an explosion, tank rupture, or fire.

To ensure complete cabinet security, the Pad Mounted transformer tank and cabinet base are equipped with cleats that secure the transformer to the pad.

If gaps remain between the cabinet and pad after clearing the cabinet, the installation will lack the necessary security to prevent public tampering. Fill the gaps with a durable mortar sealant.

Step Seven: External Inspection

Pad Mounted Transformers that are new or that are being activated following a period of storage should be properly inspected prior to being connected to the power distribution system to identify any damage that happened during storage.

Inspect the Pad Mounted transformer’s exterior for nicks, dents, and scratches. Repair any damage to weather-resistant finishes as soon as possible.

Seals on the tank cover and manhole/handhole cover, as well as all gaskets or seals on bushings, gauges, fuses, and operating devices, should be inspected for signs of insulating liquid seepage.

Before the Padmounted transformer is placed in operation, repair any leaking or incorrectly tightened gaskets and seals.

Under typical circumstances, the Pad Mounted transformer leaves the manufacturer with a modest positive pressure in the oil tank.

However, depending on the changing air conditions, the unit may arrive in a vacuum (negative pressure).

While this is not causing for alarm, the prolonged lack of either negative or positive pressure may suggest a leak at a gasket seal or tank seam, necessitating additional inspection.

Remove the pressure release valve and pressurize the headspace to check for leaks.

The pressure used in the test should not exceed 7 psig.

Maintain the established pressure for at least four hours to check that all seals are functioning properly.

Step Eight: Internal Inspection

If the exterior check reveals no signs of damage, no pre-service interior inspection may be necessary.

If an inspection of the Pad Mounted transformer’s interior is required, it must be opened by removing the manhole/handhole or tank lid.

Pre-service interior checks should be limited to documenting faults or damage that may impair the pad mount transformer’s operation.

Moisture on the underside of the tank cover or manhole cover, loose, displaced, or damaged components, broken or loose connections, and polluted insulating fluids should all be inspected.

Installing an electrical Pad Mounted transformer on-site can be challenging, much more so if this is your first time or you are unfamiliar with electrical transformers.

To begin, the electrical transformer must be handled cautiously to avoid internal damage, which would result in inoperable power equipment.

It is critical to observe all safety procedures and to provide protective equipment to the construction worker who will be handling the transformer.

These suggestions apply to both dry-type and liquid-filled Pad Mounted transformer installations.

It is critical that you understand which acceptance tests must be performed.

All relevant acceptance tests should be conducted in accordance with ANSI/IEEE and NEMA standards.


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