Technical Specification
CG Power and Industrial Solutions manufactures an extensive line of Oil-Immersed Three-Phase Distribution Transformers engineered for medium-voltage electricity distribution across utility networks, industrial manufacturing complexes, oil and gas processing facilities, commercial infrastructure, and renewable energy farms. Available in ratings from 50 kVA up to 5,000 kVA with primary voltages up to 36 kV (including standard 11 kV, 13.8 kV, 22 kV, 24 kV, and 33 kV systems), these transformers deliver rock-solid reliability under harsh outdoor climatic conditions. Offered in both Hermetically Sealed Corrugated Tank configurations (where flexible cooling fins absorb oil expansion without atmospheric air exchange, eliminating moisture contamination and oil oxidation) and traditional Conservator Tank designs with silica gel breathers. Constructed with low-loss cold-rolled grain-oriented silicon steel cores and high-conductivity copper or aluminum foil windings, CG distribution transformers comply with the latest eco-design energy efficiency standards, lowering operational electricity losses while providing maintenance-free operational life exceeding 30 years.
Broad Capacity Range: Available from 50 kVA up to 5,000 kVA for pole-mounted, pad-mounted, or substation outdoor installations
Medium Voltage Coverage: Primary voltages up to 36 kV (standard 4.16 kV, 11 kV, 13.8 kV, 24 kV, 33 kV) with low voltage secondaries (220V, 380V, 415V, 480V)
Hermetically Sealed Tank Architecture: Corrugated elastic fin walls expand and contract with oil temperature, completely isolating fluid from ambient moisture and oxygen
High Energy Efficiency: Engineered to meet stringent global eco-design benchmarks (Tier 2 EU / DOE 2016 / BEE Star ratings) with ultra-low no-load losses
Product Engineering
Select kVA rating, primary/secondary voltages, tank configuration, and winding metallurgy.
Model Code
Store in an upright position on level concrete pads. Never lift the transformer by the cooling fins or high-voltage bushings; always use designated tank lifting lugs.
Check that the off-circuit tap changer handle is firmly locked into the desired tap notch before energizing. Never operate the tap changer under load.
Verify grounding continuity of the tank grounding pads to the substation earth grid before energizing primary bushings.
Traditional distribution transformers utilize a conservator expansion vessel open to the atmosphere through a desiccant silica gel breather. Over time, saturated silica gel permits ambient humidity and oxygen to infiltrate the tank, degrading oil dielectric breakdown voltage and accelerating cellulose insulation aging.
CG Hermetically Sealed Distribution Transformers eliminate this failure mode entirely. The transformer tank is completely sealed under vacuum with zero internal air cushion. Volumetric expansion and contraction of the insulating oil during load cycling is absorbed by the elastic bending of precision-formed corrugated fin radiator walls. Because the dielectric fluid never contacts atmospheric oxygen or moisture, oil dielectric strength remains pristine for decades without requiring routine sampling, filtering, or desiccator maintenance.
Eliminates regular maintenance shutdowns for oil dielectric testing and silica gel replacement
Compact physical envelope fits easily inside prefabricated compact substations (CSS) and compact package kiosks
Low operating noise levels achieved by step-lap core joints make them ideal for residential and urban utility placement
Factory leak tested with helium mass spectrometry to assure absolute hermetic enclosure integrity
For mission-critical industrial plants and distribution substations, CG hermetically sealed transformers can be outfitted with an integrated multi-function safety relay (such as DMCR or RIS). This device consolidates four critical diagnostic sensors into a single compact housing mounted directly on the tank cover.
