Distribution Transformers

WR distribution transformers are designed and manufactured in North America to meet the requirements of varied industrial and commercial applications. The company manufactures dry-type electrical transformers intended for installations where the reliability of the electrical power source and manufacturing quality are essential. WR equipment is notably used in mines, data centers, pulp and paper facilities, aluminum smelters, microgrids, as well as in various infrastructures such as hospitals, factories, schools, pharmacies, and supermarkets. 

The design can be adapted to the electrical and physical characteristics of the project. WR has the capability to manufacture high-power units exceeding 20 MVA, with voltages reaching up to 49 kV and insulation classes reaching up to 220 kV BIL. This manufacturing capability allows the team to focus as much on the electrical characteristics of the transformer as on its integration into the installation for which it is intended. 

Transformer construction relies in particular on copper or aluminum windings. The coils are vacuum pressure impregnated using the VPI process with a polyester resin to ensure the impregnation of the windings and their insulation. Depending on the voltage level and the required insulation class, the windings can be manufactured in layers or in discs. For certain applications, WR can also use foil for low-voltage windings to reduce losses associated with eddy currents and increase their short-circuit strength. The transformers are equipped with UL-approved 220 °C class insulation.

The core also represents an important design element. WR uses grain-oriented steel with high magnetic permeability. Magnetic flux density is kept below the saturation point to limit core losses and reduce sound levels. The steel is precision cut, carefully stacked, and coated with a corrosion-resistant finish. For larger capacity units, the design can also incorporate an air gap to promote air circulation and cooling.

Integrating the transformer into the facility can also be taken into account right from manufacturing. Busbars can be manufactured and installed to coordinate with low- or high-voltage switchgear. Transition compartments can also be added, particularly to allow top cable entry and facilitate connections. Cable supports can complete the assembly to simplify and secure the installation. Flexible braids can also be incorporated to limit vibration transmission to the switching devices connected to the transformer. 

Prior to delivery, WR transformers undergo a testing process in the company's ISO/IEC 17025 certified laboratory. Routine testing notably includes dielectric testing, excitation at rated voltage, polarity, ratio, winding resistance, as well as load losses and impedance. Additional tests can also be performed, particularly for temperature rise, basic impulse insulation level (BIL), partial discharge, or sound level. Testing is carried out in accordance with applicable standards, including IEEE C57.12.91-2011 and CSA 22.2 #47-13 for dry-type, air-cooled transformers.