Technical Specification
CG Power and Industrial Solutions Limited (formerly Crompton Greaves) is a globally recognized pioneer in Extra High Voltage (EHV) and Ultra High Voltage (UHV) power transmission infrastructure. Engineered to ensure rock-solid grid stability across national interconnections, thermal/hydro power generating stations, and heavy industrial mega-substations, CG Power Transformers are manufactured in ratings up to 765 kV voltage class and capacities up to 1,000 MVA. Built with high-permeability, laser-scribed grain-oriented silicon steel (CRGO) cores and continuously transposed conductors (CTC) to slash no-load and load losses, these transformers deliver market-leading efficiency and low total cost of ownership. Every unit undergoes rigorous 3D finite-element electromagnetic and thermal modeling to ensure superior dynamic withstand against severe transmission network short-circuits. Outfitted with high-reliability On-Load Tap Changers (OLTC), condenser or polymer high-voltage bushings, automated ONAN/ONAF/OFAF radiator cooling banks, and integrated digital online monitoring systems (DGA and fiber-optic winding temperature sensors), CG EHV transformers are the premier choice for regional utilities and heavy industrial complexes across the Americas.
Ultra-High Voltage Class: Engineered for transmission grids and power plants up to 765 kV class and single/three-phase capacities up to 1000 MVA
Superior Short-Circuit Strength: 3D finite-element analysis verified windings withstand severe external network faults and electrodynamic forces
Low Loss Core Design: Step-lap mitered core built from top-tier domain-refined grain-oriented silicon steel (CRGO) minimizes hysteresis and eddy losses
On-Load Tap Changing (OLTC): High-speed vacuum or resistor-type tap changers provide smooth, uninterrupted voltage regulation under load
Engineering & Sizing
Select primary/secondary voltage ratings, MVA capacity, cooling mode, and online diagnostic options.
Model Code
Heavy transport logistics require route surveys for bridge weight ratings and over-dimensional clearance. Units are shipped nitrogen-filled without oil.
Oil filling must be executed under high vacuum (< 1 mbar) with oil filtration and dehydration machines to eliminate moisture and air pockets.
Perform field ratio, winding resistance, insulation resistance, frequency response analysis (SFRA), and dielectric dissipation factor tests prior to initial energization.
Extra High Voltage transmission grids face extreme electrodynamic stresses caused by sudden line faults, lightning surges, and continuous switching transients. CG Power Transformers are engineered to withstand these operational hazards through conservative structural margins, disc-interleaved winding designs, and high-density pressboard insulation clamping systems.
The core architecture utilizes step-lap mitered lamination joints manufactured from cold-rolled grain-oriented (CRGO) electrical steel with localized domain refinement. This geometry eliminates magnetic flux bottlenecks at corner joints, resulting in exceptionally quiet acoustic decibel levels, minimal magnetizing inrush current, and market-leading no-load efficiency.
Windings dried under vapor-phase vacuum chambers to achieve residual moisture content below 0.5%
Tank designed to withstand full internal vacuum during oil filling and seismic acceleration levels exceeding 0.5g
Equipped with sudden pressure relief valves, Qualitrol™ electronic temperature indicators, and Buchholz protection relays
Available with environmentally friendly, high fire-point ester dielectric fluids (FR3 / MIDEL) for sensitive ecological corridors
To optimize asset longevity and transition from calendar-based maintenance to predictive condition-based maintenance, CG EHV transformers can be equipped with an integrated digital monitoring suite.
