OMEK Power™ VPI Dry Type Transformer
OMEK VPI (Vacuum Pressure Impregnated) Dry type transformer adopts a special insulation craft, called Vacuum Pressure Impregnation. The coil windings are impregnated to the insulation material mixture. Through the vacuum process, winding gaps are totally impregnated. After curing, the windings of the VPI dry type transformer get a solid insulation layer.
This design gives the dry type transformer good heat dissipation and a very competitive cost. Compared with cast resin transformers, the VPI dry type transformer has better cooling efficiency and lower cost. It is also a safe indoor alternative to oil-filled transformers where fire protection is required.
- System Overview 1
Maximum Power Rating
– Up to 10,000kVA
Primary Voltage
– Up to 25kV(AC)
Temperature Rise
– 150° standard
Basic Impulse Levels
– 10 to 95kV
Insulation
– Class H – 220°C
Transformer Core
– Non-aging, grain oriented, silicon steel
Enclosure
– NEMA 1, NEMA 3R or NEMA 4
– Additional NEMA rated and specialty enclosure options available
Cooling
– Forced air, direct water or heat exchanger system
VPI/VPE Power Transformers Features
VPI provides good moisture resistance; VPE offers an even thicker, more protective coating for harsher environments.
After impregnating, the coil windings have a better heat conducting property. This lowers the dry type transformer’s temperature rise.
It has a strong arc resistance capability and coil insulation strength. High safety and reliability.
Protected by a solid insulation layer, VPI/VPE power transformer can serve a longer lifetime.
More economical than cast resin transformers while maintaining strong electrical performance.
VPI Power Transformers Structure
The wiring terminal: Clasp type makes the connection more safer and convenient.
Oriented silicon steel sheet: The core uses high quality 0.3mm lower oriented silicon steel sheet. Laminated sheets are neat and tidy. Low loss and no-load current.
VPI craft: The coils go through a high temperature hot baking process. Low noise and vibration.
Bold wire: Using the bold wire is safer, and has a long time usage.
H level insulation system: Copper windings (specific requirements can be accepted). Also has the temperature sensor and shielding layer installed.
Ground lead
Customized Solutions for You
There’re no two same projects. OMEK VPI dry type transformer has flexible adaptability. Most of the specifications can be customizable to meet your unique needs. For example, in electrical parameters, installation space and operating conditions, etc.
The VPI dry type transformer’s voltage ratio, capacity and impedance, as well as the energy efficiency level can be customized to meet your needs.
You have many protection levels you can choose from, from IP00 to IP54. Whether you need a beautiful paint shell or no shell design, we can satisfy you.
OMEK VPI dry type transformer can be customized to meet high altitude, high-humidity or corrosive atmospheric environment.
To achieve intelligent operation and maintenance, we provide options for sensors for partial discharge, load monitoring, and predictive maintenance.
Applications
FAQs
Have any questions? We’re here to help you out.
A VPI (Vacuum Pressure Impregnated) dry type transformer is a coil fully impregnated with insulating varnish under vacuum and pressure.
It provides strong moisture resistance, improved mechanical strength, and stable performance for indoor commercial/industrial power distribution.
It’s a cost-effective dry type solution with reliable cooling and easy maintenance.
VPI transformer and cast resin transformer are for different needs.
From the overall performance, we can say the cast resin transformer has higher performance than the VPI type. Because it uses epoxy resin casting craft and prove better in insulation performance and heat resistance. It is more suitable for the places that require no power outage, such as the hospitals and data centers. For normal places such as the ordinary factory production line, office buildings, a VPI dry type transformer is enough since it is cost lower than the case resin transformer.
Both VPI and VPE use varnish insulation. But their protection levels are different:
– VPI (Vacuum Pressure Impregnation): Single varnish cycle, good moisture resistance, ideal for normal indoor use.
– VPE (Vacuum Pressure Encapsulation): Multiple varnish coats and thicker encapsulation layer, giving better protection against moisture, chemicals, and salt-laden air.
VPE = enhanced protection. It is often chosen for coastal or mildly corrosive environments.
– Cast Coil (Cast Resin): Coils are fully embedded in epoxy resin, forming a hard solid block. Offers top-tier environmental, moisture, and mechanical protection.
– VPI: Coils are varnish-impregnated rather than cast solid. Better heat dissipation and maintainability, and lower cost.
Summary:
Cast coil = highest protection; VPI = economical, reliable, and easier to service.