Engineered for Harsh Environments & Zero Atmospheric Contamination
URJA Techniques (India) Pvt. Ltd. engineers and manufactures custom hermetically sealed oil-immersed transformers rated up to 3150 kVA in the 33 kV voltage class. Built with completely leak-proof corrugated tanks or nitrogen-cushioned chambers, these units are specifically designed for continuous operation without requiring conventional conservator tanks or routine desiccant maintenance.
Preserved Dielectric Strength Without Conservators
In standard oil-immersed transformers, the expansion and contraction of insulating liquid causes breathing of atmospheric air, leading to moisture accumulation, oxidation of transformer oil, and gradual breakdown of cellulose insulation. URJA's hermetically sealed transformers eliminate this degradation cycle entirely.
By sealing the transformer tank completely from the surrounding atmosphere, dielectric properties remain stable over decades. Thermal expansion is compensated by the dynamic elasticity of precision-folded corrugated fin walls or an engineered inert gas headspace, significantly extending operating life in high humidity, coastal, desert, and chemical plant environments.
Design Specifications & Technical Parameters
Every hermetically sealed unit is individually engineered to comply with IEC 60076, ANSI C57, and IS standards, matching the exact climatic and load criteria of your utility or industrial project.
| Power Rating | Up to 3150 kVA (Custom engineered configurations available on request) |
|---|---|
| Voltage Class | Primary voltages up to 33 kV; Secondary voltages customized to 400V, 415V, 433V, 6.6kV, or 11kV |
| Dielectric Cooling Medium | High-grade inhibited/uninhibited mineral insulating oil or synthetic/natural ester fluid (Fire point > 300°C, Flash point > 275°C) |
| Expansion Compensation | Elastic corrugated tank walls (fin flexibility) or permanent dry nitrogen cushion headspace |
| Cooling Classification | ONAN (Oil Natural Air Natural) / KNAN (for ester dielectric fluids) |
| Core Material | Low-loss, high-permeability Cold Rolled Grain Oriented (CRGO) silicon steel laminations with step-lap mitered joints |
| Winding Material | High-conductivity Electrolytic Copper (Cu) or Electrical Grade Aluminium (Al) with Class A thermal insulation |
| Vector Group & Frequency | Dyn11, Dyn5, YNd11 or custom configurations; 50 Hz / 60 Hz operations |
| Applicable Standards | IEC 60076, IEEE/ANSI C57, IS 2026, IS 1180, BS 171 |
| Corrosion Protection | Shot-blasted steel enclosure treated with epoxy-primer and polyurethane or C5-M marine-grade offshore multi-coat finish |
Why Procurement Teams Specify URJA Sealed Units
Zero Maintenance
No conservator tank, no silica gel breathers to monitor or replace, and zero need for periodic oil sampling or de-sludging under typical duty.
Compact Footprint
The absence of an overhead conservator allows for reduced overall height, making these units ideal for compact package substations and indoor vaults.
Severe Ambient Resilience
Fully encapsulated tanks isolate the core and coils against saline coastal fogs, abrasive desert dust, chemical vapors, and tropical humidity.
Typical Project Sectors & Deployment Sites
Our hermetically sealed units provide uninterrupted step-down transformation across mission-critical facilities worldwide: