COIL
Power Transformer Manufacturer
Engineered to
Hold the Grid.
0.5 MVA to 500 MVA. Distribution to EHV transmission. Built for utility grids, industrial plants, and urban substations that cannot afford downtime.
Core Type
CRGO Laminated
Efficiency: 99.4%
Every unit spec'd
to the last milliohm.
From core lamination to final SFRA sweep — each transformer leaves our facility with a complete type-test dossier and factory acceptance test report.
Voltage Range
11 kV – 500 kV
MVA Range
0.5 – 500 MVA
Cooling Class
ONAN / ONAF / OFAF
Tap Changer
OLTC / DETC
Manufacturing Walk
From ore to operating voltage —
four bays, zero shortcuts.
The magnetic heart of every transformer.
Cold-rolled grain-oriented steel, stacked to micron tolerances.
CRGO silicon steel laminations are cut to profile and stacked in a step-lap configuration that reduces no-load losses by up to 15% versus conventional butt-lap joints. Each core is banded, torque-checked, and swept for hot spots before the first conductor turn is wound.
Core Material
CRGO M3 / M4 Grade
No-Load Loss
≤ 0.18 W/kg at 1.7T
Stacking Factor
≥ 97.5%
Configuration
Step-Lap, 5-step
Where current becomes field.
Oxygen-free copper conductor. Wound under tension, insulated in Kraft.
HV and LV windings are executed on precision CNC winding machines. Conductor transpositions are designed to minimize eddy-current losses. Nomex-reinforced Kraft paper insulation is applied between layers. Each winding is vacuum-dried and impulse-tested before core assembly continues.
Conductor
OFC Continuously Transposed
Insulation
Kraft / Nomex Hybrid
Turn Ratio Accuracy
± 0.1%
Impulse Test
1.2/50 µs, Full Wave
Mechanical integrity before oil fill.
Core-coil assembly lowered into fabricated steel tank under clean-room conditions.
The assembled core-coil unit is inspected for dimensional conformance, then lowered into a blast-cleaned, painted steel tank. Conservator, buchholz relay, and OLTC are fitted. The unit is vacuum-processed to remove moisture, then filled with inhibited mineral oil or synthetic ester dielectric fluid.
Tank Material
IS 2062 Structural Steel
Dielectric Fluid
Mineral / Ester (IEC 60076-14)
Vacuum Processing
< 0.5 mbar residual
Cooling
ONAN / ONAF / OFAF
No exceptions. No waivers.
Every unit exits with a complete KEMA-witnessed test dossier.
Routine tests — ratio, impedance, no-load and load loss, insulation resistance — are performed on every unit. Type tests including temperature rise, lightning impulse, and short-circuit withstand are performed at NABL/KEMA-accredited facilities. The complete test report ships with every transformer.
Routine Tests
IEC 60076-1 Full Suite
Type Tests
KEMA Witnessed
Short-Circuit
IEC 60076-5 Verified
Delivery
16–52 Weeks, Ex-Works
Standards & Certifications
The standards that
grid operators require.
Every Coil transformer is designed and tested to international standards. Type-test certificates are available for review during technical evaluation. No unit ships without a complete test dossier — routine tests performed on-site, type tests at KEMA-accredited external laboratories.
Power Transformers
Design, manufacturing, testing and commissioning for voltage up to 765 kV
International Electrotechnical Commission
Short-Circuit Withstand
Ability to withstand short-circuit mechanical and thermal stresses without deformation
KEMA Accredited Laboratory
Liquid-Immersed (Ester)
Requirements for transformers using natural and synthetic ester dielectric fluids
International Electrotechnical Commission
Renewable Integration
Specific requirements for wind, solar, and hybrid renewable energy transformers
International Electrotechnical Commission
Indian Standard
Parts 1–5: General requirements, temperature rise, insulation levels, short-circuit
Bureau of Indian Standards
Independent Witness Testing
Full type test suite witnessed and certified by KEMA at NABL-accredited facility
KEMA / DNV