Overview
The JDJJ2-35/JDJJF2-35L is a 35kV outdoor single-phase oil-immersed voltage transformer designed for high-voltage measurement and protection applications. It uses an oil-immersed insulation system that ensures superior thermal dissipation, making it suitable for continuous operation under heavy electrical loads in harsh outdoor environments.
Available in accuracy classes 0.2, 0.5, 1.0, and 3P, the series supports both precision metering and protective relaying needs. The JDJJ2-35 offers a standard ratio of 35/√3 : 0.1/√3 : 0.1/3 kV with 800VA thermal limit output, while the JDJJF2-35L adds a residual voltage winding for ground fault detection. Compliant with GB20840.3-2013 and IEC61869-3:2011, it operates reliably across a wide temperature range (-40°C to +40°C) in polluted or extreme climates.
Key Ratings Snapshot
| Parameter | Rating |
|---|---|
| System Voltage | 35 kV |
| Insulation Type | Oil-immersed |
| Primary Voltage | 35/√3 kV |
| Secondary Voltages (JDJJ2-35) | 0.1/√3 kV, 0.1/3 kV |
| Secondary Voltages (JDJJF2-35L) | 0.1/√3 kV, 0.1/√3 kV, 0.1/3 kV |
| Accuracy Classes | 0.2, 0.5, 1.0, 3P |
| Thermal Limit Output (JDJJ2-35) | 800 VA |
| Thermal Limit Output (JDJJF2-35L) | 600 VA |
| Phase | Single-phase |
| Installation Environment | Outdoor |
| Operating Temperature | -40°C to +40°C |
| Standards | GB20840.3-2013, IEC61869-3:2011 |
Construction
The JDJJ2-35/JDJJF2-35L features a robust oil-immersed construction with a fully enclosed oil tank that prevents moisture ingress and oil oxidation, significantly extending service life. The core and windings are immersed in high-grade insulating oil, which provides excellent dielectric strength and efficient heat transfer during continuous high-load operation. The porcelain bushings are designed for outdoor use with increased creepage distance to withstand moderately to heavily polluted environments. All external hardware is corrosion-resistant, and the unit is mounted on a welded steel base for secure foundation installation. This construction ensures long-term reliability in extreme ambient conditions from -40°C to +40°C without performance degradation.
Technical Parameters
Service Conditions
- Installation position: Outdoor substations, switching stations, or transmission networks
- Ambient temperature: -40°C to +40°C
- Altitude: ≤ 1000m (standard), higher altitude available on request
- Insulation: Oil-immersed (superior thermal dissipation)
- Frequency: 50Hz or 60Hz
- Phase configuration: Single-phase (use three units for three-phase systems)
- Enclosure: Fully enclosed oil box (prevents oil aging)
- Maintenance: Periodic oil testing and seal inspection required
Technical Parameters
The JDJJ2-35/JDJJF2-35L series are outdoor oil-immersed single-phase voltage transformers rated for 35kV systems. They operate within an ambient temperature range of -40°C to +40°C, at altitudes up to 1000m (with options for higher), and comply with GB20840.3-2013 and IEC61869-3:2011 standards.
| Type | Rated
Voltage (kV) |
Accuracy class /
Rated output (VA) |
Max.
output (VA) |
Rated
insulation (kV) |
|---|---|---|---|---|
| JDJ2-35 | 33/0.1 | 0.2-50 0.5-150 1.0-300 |
800 | 40.5 / 80 / 185 |
| 35/0.1 | ||||
| JDIF2-35L | 35/0.1/0.1 | 0.2/0.5-20/30 | 600 |
Installation & Wiring
Outline Dimensions
Overall dimensions are consistent across models: height is 1055±5mm and base width is 435mm. The JDJJ2-35 weighs 103kg, while the JDJJF2-35L weighs 110kg. Mounting is provided on a 400×250mm pattern. Maintain a minimum clearance of 600mm around the unit for maintenance access and oil sampling.
Wiring Diagram
The JDJJ2-35 and JDJJF2-35L support multiple wiring configurations: Y/Δ (three windings) for standard voltage transformation and ground fault detection, or Y/Y/Δ (four windings) for comprehensive metering and protection. Primary terminals A, B, C connect to the 35kV system. Secondary outputs include a, b, c, n for metering and protection circuits, and da, dn for open-delta ground fault detection. The JDJJ2-35 provides 5-M10 secondary terminals, while the JDJJF2-35L provides 7-M10 terminals in the bottom terminal box. Ensure correct polarity and phase sequence during installation.
Selection & FAQs
Selection Guide
- Choose the correct model: Select JDJJ2-35 for standard voltage measurement (800VA thermal limit) or JDJJF2-35L if ground fault detection is needed via its residual voltage winding (600VA thermal limit).
- Match accuracy class to application: Use 0.2 for revenue metering, 0.5 for monitoring, 1.0 for general measurement, and 3P for protection circuits.
- Verify burden compatibility: Ensure the connected load (meters, relays) does not exceed the rated output to maintain specified accuracy and avoid overheating.
- Confirm environmental suitability: The transformer is rated for ambient temperatures from -40°C to +40°C and altitudes up to 1000m; verify these match your site conditions.
- Evaluate maintenance resources: Oil-immersed units require periodic oil testing and seal inspections—ensure your team can support this maintenance schedule.
- Consider thermal performance needs: For continuous heavy-load operation, the oil-immersed design offers better heat dissipation than cast-resin alternatives.
Frequently Asked Questions
Q1: Which accuracy class is suitable for revenue metering?
The 0.2 class is recommended for revenue metering applications. It provides 50VA rated output at this accuracy level per IEC61869-3:2011. Contact us for factory calibration certificates.
Q2: Can this 35kV voltage transformer operate in extreme cold?
Yes, it operates reliably in ambient temperatures from -40°C to +40°C. The fully enclosed oil box prevents oil aging and ensures superior thermal dissipation. Confirm specific cold-climate oil grades with our engineers.
Q3: How do I configure this for a three-phase system?
This is a single-phase transformer, so you must use three units connected appropriately for three-phase systems. It is designed for outdoor substations and switching stations. Verify connection diagrams before installation.
Q4: What international standards does this outdoor transformer comply with?
The JDJJ2-35 series complies with IEC61869-3:2011 and GB20840.3-2013 standards. Rated insulation levels are 40.5/80/185kV. Request the specific type test reports for your project during procurement.
Q5: Are higher altitude versions available for mountainous substations?
Standard models are rated for altitudes up to 1000m. Higher altitude configurations are available upon request to ensure proper dielectric performance. Specify your exact site elevation for factory confirmation.
Q6: Where are these oil-immersed voltage transformers typically applied?
They are primarily used in outdoor substations, switching stations, and transmission networks for voltage measurement. The oil-immersed design provides excellent thermal dissipation for continuous 35kV system operation.