Dry Substation (VPI)

Durable. Reliable. Engineered for Excellence.

MGM Transformers’ Dry Substation (VPI) transformers are built to meet the demands of modern applications where performance, longevity, and environmental safety are non- negotiable. Designed with precision and manufactured using cutting-edge technology, our VPI transformers offer a seamless blend of innovation and reliability.

Key Features:

Voltage ratings: 600 V to 34.5kV
Power Ratings: 500kVA to 10,000kVA
Custom high voltage/low voltage switchgear interface designs
Non-standard substation solutions for unique challenges
Low partial discharge levels for extended life
White label options available

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STANDARD FEATURES

DOE 2016 Efficiency Compliant
UL/CUL/CE/CSA listings
Aluminum or Copper Windings
50/60/400 Hz
220 °C Insulation
Vacuum Pressure Impegnated
150°, 115° or 80 °C Temperature Rise
IEEE C57.12.01
Seismically Certified per ASCE/SEI 7-05
OSHPD OSP Pre Approval

GENERAL CONSTRUCTION

Coils are Vacuum Pressure Impregnated (VPI) with solventless polyester resin, ensuring complete impregnation of the windings and insulation. The finished VPI coils are incredibly strong, readily dissipate heat and are protected against moisture, dirt, and most industrial contaminants. Winding designs vary based on voltage, BIL and application. For all units the insulation system will be 220 °C

ENCLOSURE

The standard enclosure is NEMA 1, Category C construction. Enclosures are suitable for lifting, jacking, rolling or skidding with provisions for lifting from the transformer base. High voltage and low voltage ANSI ground pads are provided.

The enclosure paint finish is neat, clean and highly resistant to corrosion. Metal surfaces are thoroughly cleaned of scale, oil, grease, rust and other foreign matter before painting. Unless specified otherwise, paint color shall be ANSI 61 (light gray). NEMA 3R outdoor enclosures available.

CORE

The transformer cores are constructed of non-aging, high grade, grain oriented silicon steel laminations with high magnetic permeability. Magnetic flux densities are kept well below the saturation point. Core laminations are free of burrs and stacked without gaps. Mitered construction cores standard for low loss and high efficiency. The core clamping brackets are designed to provide even distribution of clamping forces to the core yokes and legs.

FORCED AIR COOLING

All units rated 750 kVA and higher can have added thermostatically controlled fans to increase the output capacity of the unit and give a forced air-cooled rating of 33% above the self-cooled rating. Control wiring (wire markers included), a thermal sensor and a fan controller will be supplied.

AUDIBLE SOUND LEVELS

The transformer shall be designed to meet IEEE sound levels for dry-type transformers. As an option, transformers designed at -3dB below IEEE C57.12.01 standard sound levels are available.

PRODUCT COORDINATION

When specified, transformers can be close-coupled to a multitude of High Voltage and Low Voltage Switchgear.

TESTING

Each transformer shall receive the following standard production tests in accordance with IEEE C57.12.91

Resistance test
Polarity & phase relation test
Turns ratio test
No-load loss & exiting current test
Impedance and load-loss test
Applied potential test
Induced potential test
Additional optional tests available upon request

SPECIAL APPLICATIONS

Low loss designs
Rectifier transformer designs
Special ambient temperature designs
High overload capacity designs
Special/low sound level designs
50 Hz designs
Series/parallel windings
Retrofit to specific dimensions
K-factor ratings
Special Paint
Auto transformers
Liquid filled transformer replacement