An Earthing Transformer (also known as a Grounding Transformer or Neutral Grounding Transformer) is a critical protection apparatus used in three-phase power systems to provide a neutral reference point for ungrounded Delta-connected power networks or ungrounded Wye systems. Urja Techniques (India) Pvt. Ltd. manufactures high-reliability earthing transformers engineered to limit transient over-voltages, facilitate system grounding, and ensure rapid, dependable clearance of phase-to-ground faults.
Designed to withstand severe thermal and mechanical stresses during short-circuit fault conditions, our grounding transformers utilize optimized Zig-Zag (Zn) or Star-Delta (Ynd) winding configurations. Every unit is manufactured in accordance with international power standards including IEC 60076, IS 2026, and IEEE C57.32, guaranteeing continuous operating performance for utility substations, renewable energy installations, and heavy industrial facilities worldwide.
Our earthing transformers are tailored to site-specific fault current magnitudes, zero-sequence impedance requirements, and duty cycles.
| Specification Parameter | Design Range & Options |
|---|---|
| Voltage Rating Class | Up to 33 kV (3.3 kV, 6.6 kV, 11 kV, 22 kV, 33 kV) |
| Power / Fault Rating | Up to 5 MVA (50 kVA to 5000 kVA short-time / continuous rating) |
| Winding Vector Group | Zn (Zig-Zag / Interstar) or Ynd11 (Wye-Delta) |
| Cooling Type | ONAN (Oil Natural Air Natural) / OFWF / Dry Type (VPI/CRT) |
| Conductor Material | High-grade Electrolytic Copper (Copper Foil / Enamelled Wire) |
| Core Material | Low-loss, Cold Rolled Grain Oriented (CRGO) Silicon Steel |
| Fault Duration Duty | 10 Seconds, 30 Seconds, 60 Seconds, or Continuous Auxiliary Loading |
| Applicable Standards | IEC 60076-6, IS 2026, IEEE C57.32, ANSI / NEMA |
| Type Testing Credentials | Type-tested by CPRI (Central Power Research Institute) & ERDA |
Utilizes a three-phase winding connected in an interstar pattern. The Zig-Zag design offers maximum zero-sequence impedance efficiency under normal operation while presenting low zero-sequence impedance during ground faults, minimizing fault loop resistance.
Engineered for integration with Neutral Grounding Resistors (NGR) or Neutral Grounding Reactors. Controls phase-to-ground fault current to a safe, predefined level, preventing generator and transformer winding damage.
Combines grounding neutral functions with a low-voltage secondary winding (e.g., 415V / 433V) to supply local station power to substation auxiliary systems, lighting, and cooling equipment simultaneously.
Robust structural clamping and high-dielectric insulation allow windings to withstand rapid temperature rises during short-duration high-current ground faults.
Tailored core geometry and winding copper section calculations ensure precise Zero-Sequence Impedance matching site-specific protective relaying needs.
Constructed with prime-grade, highly permeable CRGO silicon steel laminations to minimize core losses and operating heat dissipation.
Engineered for extreme ambient temperatures (-25°C to +50°C), desert environments, tropical climates, and high-altitude substation sites.
Urja Techniques operates an ISO 9001:2015, ISO 14001:2015, and ISO 45001:2018 certified manufacturing facility in Mumbai, India. Every manufactured earthing transformer undergoes extensive Routine Tests and Quality Audits in accordance with IEC 60076 and IS 2026 specifications.
Winding resistance, Voltage ratio & Vector check, Zero-sequence impedance measurement, Insulation resistance, Separate-source AC withstand.
CPRI & ERDA certified Temperature Rise test, Lightning Impulse withstand test, Short-circuit dynamic withstand capability test.
With active exports reaching over 40 countries across Africa, the Middle East, Europe, and Southeast Asia, Urja Techniques delivers grounding equipment for key global industrial sectors:
Contact our engineering specialists today to discuss your project requirements, request single-line diagram (SLD) reviews, or obtain competitive FOB/CIF quotation pricing for international delivery.