Overview
The JSJB-6/10G is a three-phase, indoor oil-immersed voltage transformer rated for 6kV and 10kV AC power systems. It features oil-filled insulation and provides a standardized secondary output of 100V for accurate voltage transformation in medium-voltage applications.
Designed for systems with non-directly-earthed neutral points, it meets requirements for voltage measurement, energy metering, and relay protection circuits. The unit complies with relevant IEC and national standards for accuracy, safety, and performance in indoor distribution environments such as metering panels and substation switchgear.
Key Ratings Snapshot
| Parameter | Rating |
|---|---|
| Primary Voltage | 6kV / 10kV |
| Secondary Voltage | 100V |
| Phase Configuration | Three-phase |
| Insulation Type | Oil-immersed |
| Installation Environment | Indoor |
| System Neutral | Non-directly-earthed |
| Accuracy Class (Metering) | 0.2 / 0.5 |
| Accuracy Class (Protection) | 3P / 6P |
| Frequency | 50Hz |
| Cooling Method | Natural oil convection |
| Short-Time Thermal Withstand | As per IEC 61869 |
| Degree of Protection | IP00 (indoor use only) |
Model Designation
- J: Voltage transformer
- S: Three-phase structure
- J: Oil-filled / oil-immersed insulation type
- B: Protection type / protection-related design code
- 6 / 10: Rated voltage grade: 6kV or 10kV
- G: Product variant / design code according to manufacturer specification
Construction
The JSJB-6/10G features a robust tank-type construction filled with high-quality insulating oil, providing both electrical insulation and cooling. The core and windings are fully immersed in oil within a sealed metal enclosure, ensuring stable thermal performance and long-term reliability. Primary and secondary windings are arranged concentrically around the magnetic core, optimized for low leakage reactance and high accuracy. The terminal bushings are designed for secure indoor connections, and the unit includes oil expansion compensation to accommodate thermal cycling. All materials comply with standard requirements for fire resistance and environmental safety in indoor medium-voltage installations.
Technical Parameters
Service Conditions
- Altitude: not over 1000m
- Ambient temperature: -25°C to +40°C
- Relative humidity: less than 85% at 20°C
- Vibration resistance: The product has passed direct vibration testing with an intensity of 0.4g three-sine waves, equivalent to a high seismic intensity condition according to the product sample statement.
- Installation environment: Indoor, clean and suitable for oil-immersed medium-voltage equipment.
Technical Parameters
The JSJB-6/10G is an indoor, oil-immersed three-phase voltage transformer designed for 6kV and 10kV systems, featuring Y/Y0-12 winding connection and rated secondary voltage of 100V. It operates within an ambient temperature range of -25°C to +40°C and at altitudes not exceeding 1000m, supporting applications in voltage measurement, energy metering, and relay protection.
Voltage Transformer Data
| Type | Rated Primary Voltage (V) |
Rated Secondary Voltage (V) |
Rated Output (VA) 0.5 |
Rated Output (VA) 1 |
Rated Output (VA) 3 |
Limit Capacity (VA) |
Connection Group |
Weight (kg) |
|---|---|---|---|---|---|---|---|---|
| JSJB-6 | 6000 | 100 | 80 | 150 | 320 | 640 | Y/Y0-12 | 48 |
| JSJB-10 | 10000 | 100 | 120 | 200 | 480 | 960 | Y/Y0-12 | 105 |
Installation & Wiring
Installation Diagram
The JSJB-6/10G series must be installed in accordance with the approved project drawing, foundation layout, and specified clearances. Prior to installation, verify the tank dimensions, porcelain bushing clearance, secondary terminal location, grounding point, and adequate space for maintenance.
Wiring Diagram
- Primary terminals are accessible through porcelain bushings mounted on the tank cover.
- Secondary terminals must be connected strictly according to the approved wiring diagram.
- Phase sequence on the high-voltage side shall be A-B-C and a-b-c on the low-voltage side.
- The winding connection group is Y/Y0-12 as specified in the technical data table.
- All grounding connections must comply with applicable project electrical safety rules.
Selection & FAQs
Selection Guide
- Select the model (JSJB-6, JSJB-10, or JSJB-6/10G) based on your system voltage: 6kV systems typically use JSJB-6 with 6000V primary voltage, while 10kV systems use JSJB-10 with 10000V primary voltage.
- Choose the rated output according to the total secondary burden, which includes meters, relays, monitoring devices, terminal equipment, and wiring losses—ensuring it does not exceed the transformer’s rated capacity for the required accuracy class.
- Determine the appropriate accuracy class: Class 0.5 for high-accuracy metering, Class 1 for general measurement, and Class 3 for indication or auxiliary protection functions where lower accuracy is acceptable.
- Confirm that your system uses a non-directly earthed neutral point, as this transformer series is designed specifically for such configurations.
- Specify key ordering details including connection group (e.g., Y/Y0-12), rated frequency (50Hz or 60Hz), installation environment (indoor, altitude, temperature, humidity), and any special requirements for documentation or packaging.
Frequently Asked Questions
Q1: Can this oil-immersed voltage transformer be installed outdoors?
No, it is strictly designed for indoor installation. It requires a clean environment suitable for oil-immersed medium-voltage equipment. Contact us for outdoor-rated alternatives.
Q2: What is the maximum limit capacity for the JSJB-6 model?
The limit capacity for the JSJB-6 model is 640 VA. Rated outputs are 80 VA (0.5 class), 150 VA (1 class), and 320 VA (3 class). Confirm exact load requirements with our engineering team.
Q3: Which winding connection group does this three-phase transformer use?
It features a Y/Y0-12 winding connection group. This configuration provides a rated secondary voltage of 100V for 6kV and 10kV systems.
Q4: Is this transformer suitable for high-altitude installations above 1000m?
No, the standard service condition restricts altitude to a maximum of 1000m. High-altitude derating or custom design is required for elevated sites. Please provide site elevation for factory assessment.
Q5: What factory vibration tests are performed before shipment?
The product undergoes direct vibration testing with an intensity of 0.4g three-sine waves. This ensures compliance with high seismic intensity conditions according to the product sample statement.
Q6: How much does the standard JSJB-6 unit weigh for logistics?
The standard JSJB-6 model weighs 48 kg. Ensure your installation structure and transport logistics can accommodate this physical weight.
Q7: What are the primary applications for this 10kV voltage transformer?
It is primarily used for voltage measurement, energy metering, and relay protection in 6kV and 10kV indoor systems. Verify specific protection relay compatibility with our technical support.