HUARUI 
Oil Immersed Transformer Core and Coil Assembly
This universal oil-immersed transformer core and coil assembly is the core electromagnetic assembly for various oil-immersed distribution and power transformers. It integrates the core, high and low voltage windings, insulation support, lead taps, and overall clamping structure into a single assembly. Capacities range from 30kVA to 31500kVA, adaptable to multiple voltage levels from 6-110kV, compatible with domestic power grids and overseas 50/60Hz export projects. It can be used for new transformer installations or as a replacement for older transformers during overhauls. The entire process involves vacuum-dried oil immersion, resulting in low losses, short-circuit resistance, and low operating noise, meeting mainstream standards such as GB1094, IEC, and ANSI.
| Capacity | 30 kVA ~ 31,500 kVA |
| High Voltage | 6 kV / 10 kV / 35 kV / 110 kV and 7.2 kV / 13.8 kV / 24.94 kV / 34.5 kV |
| Low Voltage | 0.4 kV / 0.69 kV / 208Y/120V / 277/480V, etc. |
| Frequency | 50 Hz / 60 Hz (Selectable) |
| Voltage Regulation | ±2×2.5% (5 taps), Off-Circuit (No-Load) Tap-Changing |
| Connection Group | Dyn11, Yyn0 |
| Insulation Class | Class A (105℃) |
Dual energy efficiency options (high and low loss) are available, compatible with Level 1 energy efficiency and overseas DOE energy-saving standards;
Dual energy efficiency options (high and low loss) are available, compatible with Level 1 energy efficiency and overseas DOE energy-saving standards;
Vacuum oil impregnation process provides a large insulation margin, suitable for outdoor and coastal high-humidity salt spray environments;
Rationally designed heat dissipation oil circuit ensures stable temperature rise control and extends the overall lifespan of the transformer;
Size, voltage, impedance, and frequency can all be customized to suit distribution transformers, prefabricated substations, and new energy step-up transformers.
1. Core (Two Options Available)
High-Grade Grained Silicon Steel Core: 0.18~0.30mm laser-etched silicon steel, 45° fully inclined stepped five-column/three-column structure, 15%~28% lower no-load loss, low excitation current, secure clamping, shock and vibration resistant.
Iron-Based Amorphous Core (Energy-Saving Version): 0.025mm ultra-thin amorphous strip, 50%~75% lower no-load loss than ordinary silicon steel, lower temperature rise, lower noise, suitable for light-load, long-term operation.
2. High and Low Voltage Windings
All-Copper Foil Winding: T2 high-purity oxygen-free copper foil, foil-wound and argon-arc welded, balanced ampere-turns, strong short-circuit resistance;
Aluminum Foil Winding: Economical solution, lightweight, with anti-corrosion copper-aluminum transition joints.
3. Insulation System
F/H grade high-temperature resistant insulating paper, insulating cylinder, and fiberglass support strips form a complete heat dissipation and insulation channel, compatible with mineral oil and FR3 natural ester oil, with low partial discharge and aging resistance.
1. Core Material: Cold-rolled grain-oriented silicon steel sheet, amorphous alloy silicon steel sheet, silicon steel sheet magnetic flux density
2. Winding Material: Copper or aluminum
3. High and low voltage customization
4. Tap changer customization
5. Customization based on provided drawings, adapting to existing customer oil tanks
Urban and rural oil-immersed distribution transformers, European/American type box-type substations, photovoltaic energy storage step-up transformers, industrial special oil-immersed transformers, overseas export transformers, power equipment overhaul replacement parts.
