Liquid-Filled Transformer Specifications
By providing you with the exact configuration your transformer requires, the Niagara Transformer Corp. minimizes the time and cost of field installation. There are no standard models at the Niagara Transformer Corp. Our design approach ensures that you receive exactly what you need at a competitive price.
We can provide transformers with the following specialized options:
20 / 37.33 MVA On-Load Tap-Changing (LTC); Mineral Oil
Mechanical
- Coordinated HV and LV termination location
- Coordinated HV and LV elevation
- Motorized tap changer
- High seismic zones
- Class I, Division 2 environments
- Special arrangement
- Special termination arrangements
- Special dimensions
- Special footprints
- Special paint color coordination
- Skid-mounted
- Retrofit accessory location
3.25 MVA Rectifier-Duty; Mineral Oil
Electrical
- Dual, primary and secondary voltages
- Nonstandard kVA
- Nonstandard voltages
- Nonstandard BIL
- Nonstandard sound levels
- Special impedance (low or high)
- Special frequencies (25 Hz, 50 Hz, etc.)
- Low operating temperature rises
21.28 MVA Substation; Envirotemp®
General Specifications
Coils
- All coils are designed based on the customer's specific application. The kVA, voltage rating, and the application dictate the use of either circular or elliptical forms with windings as follows:
- Continuous Disk - for medium to high-voltage applications where impulse strength is important.
- Barrel - for medium-voltage and medium current applications.
- Helical - for high-current applications offering high short-circuit strength and low winding eddy current losses.
- Sheet - for low-voltage, high-current applications and the elimination of axial forces on winding short circuits.
Coils can be furnished with temperature rise ratings of 55°C above ambient. Enhanced rating of units is available for 65°C rise units.
Cores
Cores are made from high-grade, non-aging, grain-oriented, cold-rolled silicone steel. They are laminated for high magnetic permeability and low hysteresis and eddy current losses.
The Niagara Transformer Corp. offers computer-generated cores designed for the customer's specific application. Wound cores for low-power and stacked cores for highpower applications are offered. Stacked cruciform cores employ step-lap mitered, mitered, or butt-cut configurations.
Insulating Fluids
The Niagara Transformer Corp. can supply every cooling fluid currently available. Mineral Oil or Envirotemp® FR3TM typically are used outdoors. Beta, Alpha, and Silicone Fluids are offered when higher fire point liquids are needed.
Tank Design
Liquid-filled tanks are welded, oil-tight steel construction with structural bases designed to permit skidding or rolling in either centerline direction. Sealed tanks are designed to withstand, without permanent deformation, pressure greater than 25% of the maximum operating pressure. Large tank designs are suitable for full vacuum processing. The Niagara Transformer Niagara Corp. can accommodate any required orientation of terminals - from simple cable terminals to inline substation configuration, to custom terminal locations.
Types of oil preservation systems include:
- Sealed Tank Construction - where the transformer is sealed airtight and a gas space of nitrogen above the oil serves as a pressure buffer.
- Inert Gas System - where the breathing of inert gas is controlled to maintain a positive pressure of nitrogen within the transformer tank.
- Conservator Style Design - where a vented reservoir tank allows for thermal expansion and contraction of the transformer liquid. Suitable for forced oil cooling designs.
Finishes
Niagara Transformer's standard paint finish is ANSI #70 Gray. We can furnish any ANSI paint color specified, or match a paint color if a paint chip is supplied. Special finishes can be supplied on request for:
- Chemical and/or corrosive environments;
- High-humidity locations;
- Offshore and coastal, salt-laden environments.
The Niagara Transformer Corp. can provide terminal locations in any ANSI segment number requested, including any of the following individually or in any combination:
- Cover-mounted;
- Full-height air terminal chambers;
- Partial-height air terminal chambers;
- Sidewall-mounted throats;
- Sidewall-mounted flanges;
- Segregated & non-segregated isolated phase bus duct.
Cooling
Additional cooling, provided by motor-driven fans mounted on the transformer base, can be added to the transformer using single-stage, forced-air cooling to increase capacity within guaranteed temperature limits for:
- Continuous operation;
- Periods of overloading;
- Seasonal changes of loading.
