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Three-Phase Oil-Immersed Distribution Transformer
Three-Phase Oil-Immersed Distribution Transformer is a high-efficiency electrical transformer designed for three-phase power distribution systems. It plays a crucial role in stepping down primary distribution voltages to levels suitable for industrial, commercial, and residential loads. Engineered for reliability and long service life, oil-immersed distribution transformers feature robust construction, excellent cooling performance, and superior electrical characteristics that meet international standards such as IEC 60076 and related industry specifications.
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Structure & Construction of Three-Phase Oil-Immersed Distribution Transformer
Three-phase oil-immersed transformer typically comprises three single transformer windings assembled on a common magnetic core, all submerged in insulating oil within a robust steel tank. The core is made from laminated cold-rolled silicon steel to minimize core losses, and the windings are precision configured for balanced phase distribution. High-quality sealing, bushings, and cooling attachments guarantee durability and safe operation.
Features & Advantages of Three-Phase Oil-Immersed Distribution Transformer
Efficient Oil Cooling & Insulation
Filled with high-grade mineral oil, the transformer’s core and windings are fully immersed to enhance insulation and heat dissipation. This design supports stable performance under continuous load and fluctuating temperatures, whilst reducing thermal stress on internal components.
High Reliability & Durability
The iron core is typically made of cold-rolled grain-oriented silicon steel, which provides low core losses and improved magnetic properties. Precision-wound copper or aluminum windings ensure excellent electrical conductivity and strong short-circuit withstand capability.
Fully Sealed or Conservator Tank Options
Many units adopt a fully sealed tank design, preventing moisture ingress and slowing oil aging. Vacuum oil-filling technology can further improve insulation performance and extend service life.
Flexible Voltage & Capacity Range
Typical three-phase oil-immersed distribution transformers cover broad voltage classes (e.g., up to 36–40.5 kV on the high-voltage side) and capacities from 15 kVA up to 10,000 kVA or more, making them adaptable for various distribution system requirements.
Low Loss & High Efficiency
Optimized core and winding designs reduce both no-load and load losses, improving overall transformer efficiency and lowering operational costs. Enhanced designs also minimize noise emissions.
Robust Construction & Safety
Tanks are constructed from reinforced steel with corrugated walls or radiators for effective cooling and structural strength. Accessories such as pressure-relief devices, temperature gauges, and bushings improve safety and monitoring.
Applications of Three-Phase Oil-Immersed Distribution Transformer
Three-phase oil-immersed distribution transformers are widely used in:
- Utility Power Grids – stepping down transmission voltages to the distribution network.
- Industrial Facilities – serving power loads in factories, plants, and manufacturing zones.
- Commercial Complexes – providing stable supply for buildings, malls, and campuses.
- Renewable Energy Projects – integrating output from wind, solar, and mixed generation systems.
- Urban & Rural Distribution Networks – reliable voltage transformation in municipal infrastructure.
Technical Parameters of Three-Phase Oil-Immersed Distribution Transformer
| Standard | Rated capacity(kVA) | High voltage | Tapping range | Low voltage | Connection of transformer winding | No-load loss(W) | Load Loss(W) 75℃ | No-load current(%) | Impedance voltage(%) | Exterior size | Total weight(kg) | ||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| L(mm) | W(mm) | H(mm) | |||||||||||
| IEC60076-1, IEC60076-2, IEC60076-3, IEC60076-5, IEC60076-10 | 30 | 6kV, 6.3kV, 6.6kV, 10kV, 10.5kV, 11kV, Or other | ±2×2.5%, ±5% | 0.38kV, 0.4kV, 0.415kV, 0.44kV | Dyn11, Yyn0, Yzn11 | 100 | 630/600 | 1.5 | 4.0 | 690 | 510 | 920 | 275 |
| 50 | 130 | 910/870 | 1.3 | 4.0 | 730 | 510 | 960 | 340 | |||||
| 63 | 150 | 1090/1040 | 1.2 | 4.0 | 750 | 550 | 1000 | 385 | |||||
| 80 | 180 | 1310/1250 | 1.2 | 4.0 | 790 | 620 | 1020 | 450 | |||||
| 100 | 200 | 1580/1500 | 1.1 | 4.0 | 790 | 720 | 1040 | 520 | |||||
| 125 | 240 | 1890/1800 | 1.1 | 4.0 | 840 | 800 | 1070 | 625 | |||||
| 160 | 280 | 2310/2200 | 1 | 4.0 | 1070 | 670 | 1130 | 695 | |||||
| 200 | 340 | 2730/2600 | 1 | 4.0 | 1140 | 750 | 1140 | 795 | |||||
| 250 | 400 | 3200/3050 | 0.9 | 4.0 | 1200 | 800 | 1190 | 955 | |||||
| 315 | 480 | 3830/3650 | 0.9 | 4.0 | 1300 | 860 | 1210 | 1085 | |||||
| 400 | 570 | 4520/4300 | 0.8 | 4.0 | 1380 | 900 | 1240 | 1290 | |||||
| 500 | 680 | 5410/5100 | 0.8 | 4.0 | 1450 | 950 | 1300 | 1590 | |||||
| 630 | 810 | 6200 | 0.6 | 4.5 | 1500 | 970 | 1360 | 1850 | |||||
| 800 | 980 | 7500 | 0.6 | 4.5 | 1660 | 1140 | 1400 | 2210 | |||||
| 1000 | 1150 | 10300 | 0.6 | 4.5 | 1690 | 1190 | 1530 | 2570 | |||||
| 1250 | 1360 | 12000 | 0.5 | 4.5 | 1760 | 1230 | 1600 | 3115 | |||||
| 1600 | 1640 | 14500 | 0.5 | 4.5 | 1800 | 1250 | 1660 | 3520 | |||||
| 2000 | 1940 | 18300 | 0.4 | 5.0 | 1930 | 1360 | 1490 | 4060 | |||||
| 2500 | 2290 | 21200 | 0.4 | 5.0 | 2080 | 1360 | 1570 | 5105 | |||||
