Here are the key specifications and parameters for oil-immersed transformers, If you need oil-immersed transformers, please contact our company, a well-known manufacturer in China. We have various models of transformers available.

detailed information

1. Core Ratings & Electrical Parameters

- Rated Capacity (kVA/MVA): 50 kVA – 500 MVA+

- Primary Voltage (HV): 2.4 kV – 765 kV

- Secondary Voltage (LV): 120 V – 69 kV

- Frequency: 50 Hz or 60 Hz

- Vector Group: Dyn11, YNd1, Yyn0, etc.

- Impedance Voltage (%): 4% – 15% (standard: 5–8%)

- Insulation Level: BIL (Basic Impulse Level), e.g., 150 kV BIL for 33 kV class.

2. Losses & Efficiency

- No-Load Losses (Core Losses): 0.05 – 0.5% of rated power

- Load Losses (Copper Losses): 0.3 – 2% of rated power

- Efficiency: 95–99.5% (higher for larger units)

3. Cooling System

- Cooling Class (IEC):

- ONAN (Oil Natural Air Natural)

- ONAF (Oil Natural Air Forced)

- OFAF (Oil Forced Air Forced)

- Temperature Limits:

- Winding Rise: 65°C (avg) / 80°C (hotspot)

- Top Oil Rise: 60°C

4. Insulation & Oil Specifications

- Insulation Oil Type: Mineral oil, silicone fluid, or natural ester (biodegradable).

- Dielectric Strength: >30 kV (ASTM D877)

- Acidity: <0.03 mg KOH/g

- Flash Point: >145°C (mineral oil)

5. Construction & Physical Parameters

- Core Material: Grain-oriented silicon steel (CRGO).

- Winding Material: Copper or aluminum.

- Tank Type: Corrugated, radiators, or conservator with breather.

- Protection: Buchholz relay, pressure relief valve, oil temperature indicator.

- Sound Level: 50–75 dB(A) at 1m (depends on size).

6. Environmental & Safety

- Fire Point: >300°C (for less-flammable fluids).

- PCB-Free: Compliant with IEC 61619.

- Noise Standards: NEMA TR1, IEEE C57.12.90.

7. Accessories

- Tap Changer: Off-circuit (OCTC) or On-load (OLTC) ±5–15%

- Bushing Type: Porcelain or composite.

- Oil Level Gauge, Thermometers, RTD (Winding Temp).

8. Testing Standards

- Routine Tests (IEC 60076):

- Ratio, polarity, phase relation.

- No-load/load loss measurements.

- Impedance voltage.

- Dielectric tests (separate/induced AC).

- Special Tests:

- Short-circuit withstand (IEC 60076-5).

- Partial discharge (<10 pC).

9. Dimensions & Weights

- Oil Volume: 200 L – 50,000 L+

- Total Weight: 500 kg – 300 tons

- Footprint: Customized for installation.

10. Compliance Standards

- International: IEC 60076, IEEE C57.12.00

- Regional: ANSI, EN, IS, GB, JIS.

> Note: Actual specifications vary by application (distribution, power, furnace) and manufacturer. For procurement, always request detailed datasheets with test reports.