Power Transformers
VRT power transformers are custom-made to individual client specifications using advanced technologies for top performance and reliability.
They comply with the highest quality and industry standards.
Designed to Perform
VRT power transformers and mobile substations are designed for high performance. They have value-added features that ensure compliance with all relevant specifications; they are reliable, efficient and have a long service life.
Low Noise
VRT are engineered for low noise levels. Transformers larger than 50 MVA operate at noise levels of at least 10 dB below ANSI and it is possible to achieve levels of 46 – 50 dB for transformers below 50 MVA.
Hot Spray Galvanizing
VRT introduced hot spray galvanizing to help protect tanks and covers against corrosion in one of the harshest climatic regions of the world – the Dead Sea, an area 1,300 feet below sea level that experiences high temperatures, high air pressure, and many airborne salts. All external surfaces are sandblasted to “near white” and immediately hot spray galvanized with 3-4 mils of zinc, and then primed and painted with three 6 mil layers of epoxy paint. The interior tank and cover surfaces are usually painted white to facilitate contamination detection.
Vertical Winding
The main winding operations for power transformers are performed on vertical winding machines in sealed, dust-free chambers. The coil is manufactured in its natural working position to achieve more uniform tension, which assures a superior quality winding process.
Drying, Coil Dimensioning and Oil-Filling
VRT achieves identical coil height in its transformers through a special drying and compression process. The coils are dried under vacuum in a circular oven and pressed to the exact specified size. In a second stage, each phase coil block-assembly is dried and pressed again to assure absolute accuracy.
Each core and coil undergoes a vapor phase process in the oven.
Exclusive to VRT:
During the final drying, the moisture content of the transformer is reduced to less than 0.3%. This takes place at 110°C in a vacuum of less than 0.07 millibar. While still in the oven, oil is introduced to the tank; the unit is flushed and then new filtered oil is introduced. Finally, the transformer is removed from the oven and the oil is processed by the oil treatment plant.
Testing Facilities
The VRT high voltage laboratory extends over 1600 sq m (15,000 sq ft), and has a height of 21m (69 ft). All routine, type and special tests (except short circuit endurance tests) are conducted according to IEC, IEEE, ANSI, CSA and other applicable international standards for three-phase transformers up to 700 MVA 500 kV and single-phase transformers up to 500 MVA. A complete list of testing equipment is detailed in our prequalification documentation, which is available from your VRT representative.
