Overview
The JLS-6 and JLS-10 are three-phase outdoor oil-immersed combined instrument transformers designed for 6 kV and 10 kV medium-voltage distribution systems. These units integrate current transformers (CT) and voltage transformers (VT) within a single sealed, oil-filled enclosure, providing reliable insulation and thermal performance in harsh outdoor environments.
Built to metering accuracy classes 0.2 or 0.2S, they support precise active and reactive energy measurement in rural networks, industrial substations, and distribution upgrades. The design complies with Chinese national standards GB 20840.1–20840.4 series and requires a zinc oxide surge arrester within 1 m of installation for overvoltage protection.
Key Ratings Snapshot
| Parameter | Rating |
|---|---|
| System voltage class | 6 kV or 10 kV |
| Rated frequency | 50 Hz or 60 Hz |
| Configuration | Three-phase V/V (2× VT + 2× CT) |
| Accuracy class | 0.2 or 0.2S |
| Insulation medium | Oil-immersed with moisture-proof device |
| Application | Active and reactive energy metering |
| Installation environment | Outdoor |
| Applicable standards | GB 20840.1-2010, GB 20840.2-2014, GB 20840.3-2013, GB 20840.4-2015 |
| Overvoltage protection | Zinc oxide surge arrester required within 1 m |
Model Designation
- J: Combined (integrated) transformer
- L: Current transformer component
- S: Three-phase configuration
- 6, 10: Voltage class in kV
Construction
The transformer features an oil-immersed design with a sealed rectangular tank suitable for outdoor pole or platform mounting. It incorporates an integrated moisture-proof breathing device to prevent humidity ingress, ensuring long-term insulation integrity. The tank includes lifting lugs for handling, an oil level indicator for visual monitoring, a drain valve for maintenance, and a grounding bolt for safety. Internally, two single-phase voltage transformers and two current transformers are mounted on insulated supports, with all primary and secondary terminals routed through sealed bushings. This construction delivers stable thermal performance, environmental resistance, and compliance with outdoor operational demands.
Technical Parameters
Service Conditions
- Installation environment: Outdoor installation (pole-mounted or platform-mounted)
- Altitude: Not exceeding 1000 m above sea level (higher altitude requires engineering confirmation and specification adjustment)
- Ambient temperature: Consult factory for specific installation location requirements
- Pollution level: Specify pollution severity for proper selection of external insulation
- Environmental conditions: Designed for outdoor exposure; moisture-proof device protects against humidity ingress
Technical Parameters
The JLS-6 and JLS-10 series are three-phase outdoor oil-immersed combined instrument transformers rated for 6 kV and 10 kV AC distribution systems. They feature electromagnetic voltage and current transformers in V/V connection, comply with GB 20840 standards, and support metering accuracy classes 0.2 and 0.2S. Designed for ambient temperatures per site-specific consultation and altitudes up to 1000 m, they accommodate a range of primary current ratings suitable for energy metering applications.
Model Variants
| Model | Voltage | Configuration | Insulation Type |
|---|---|---|---|
| JLS-6 | 6KV | Three-phase V/V connection with two single-phase VTs and two CTs | Oil-immersed |
| JLS-10 | 10KV | Three-phase V/V connection with two single-phase VTs and two CTs | Oil-immersed |
| JLSZV-10 | 10KV | Three-phase V/V connection with two single-phase VTs and two CTs | Oil-immersed |
Voltage Transformer Data
| Type (Ratio) |
Rated Voltage (kV) |
Secondary Voltage (V) |
Accuracy
Class |
Rated Output (VA) |
Burden (VA) |
|---|---|---|---|---|---|
| Custom | 6 / √3 or 10 / √3 | 100 / √3 | 0.2 | 30–100 | Per project specification |
Current Transformer Data
| Primary Current |
Secondary Current |
Accuracy Class (Protection/ Measurement) |
Rated Output (VA) |
Short-Time Thermal Current |
Dynamic Current |
|---|---|---|---|---|---|
| 5–600A | 1 or 5A | 0.2 / 0.2S | 5–30 | 25 × In for 1 s | 62.5 × In |
Installation & Wiring
Installation Diagram
The JLS-6 and JLS-10KV oil-immersed combined transformers are designed for three-phase outdoor installation. Mount the unit securely using the designated mounting brackets as shown in the dimensional drawing. Connect primary conductors to the high-voltage terminals or bushings, ensuring proper torque and connection integrity. Maintain adequate clearance around the transformer for insulation, heat dissipation, maintenance access, and oil level inspection. Install a zinc oxide surge arrester within 1 meter of the transformer for effective overvoltage protection. Prior to energization, remove the breather plug from the moisture-proof device to enable proper breathing function.
Selection & FAQs
Selection Guide
- Select JLS-6 or JLS-10 and verify that the two-VT, two-CT V/V scheme matches the three-phase three-wire network.
- Specify the VT ratio and burden, then select the 5A–600A CT ratio and 1A or 5A secondary.
- Choose class 0.2 or 0.2S and calculate the burden of meters, terminals, fuses, and cable loops.
- Confirm outdoor insulation, pollution, altitude, temperature, grounding, and surge-arrester requirements.
- Verify the pole or platform structure, clearances, oil access, terminal diagram, breather, and certified drawing.
Frequently Asked Questions
Q1: Which AC distribution systems can use the JLS-6 and JLS-10 transformers?
They are designed for 6 kV and 10 kV outdoor AC distribution systems. They feature a three-phase V/V connection with oil-immersed insulation. Confirm your specific system voltage with our engineering team.
Q2: How do altitude and pollution levels affect outdoor installation?
Standard installation is limited to altitudes not exceeding 1000 m above sea level. Specify the local pollution severity to ensure proper external insulation selection. Engineering confirmation is required for higher altitudes.
Q3: What accuracy classes are supported for energy metering applications?
These combined instrument transformers support 0.2 and 0.2S accuracy classes for precise metering. They comply with GB 20840 standards. Specify your required accuracy class during the ordering process.
Q4: Can you describe the internal configuration of the JLS-6 model?
The JLS-6 features a three-phase V/V connection utilizing two single-phase voltage transformers and two current transformers. It is fully oil-immersed. Request detailed dimensional drawings from our sales team.
Q5: Are compliance certificates provided for these instrument transformers?
They comply with GB 20840 standards for combined instrument transformers. Specific test certificates and compliance documentation are subject to confirmation. Please reach out to our procurement team for detailed certification requirements.
Q6: Why use the JLS series for outdoor metering applications?
They provide integrated current and voltage transformation for 6 kV and 10 kV AC distribution systems. The oil-immersed design ensures durability for pole-mounted or platform-mounted installations. Consult the factory for specific ambient temperature limits.
Q7: When is factory consultation required for ambient temperature limits?
Consultation is required because ambient temperature conditions vary by specific installation location. The moisture-proof device protects against humidity ingress during outdoor exposure. Contact our technical team to verify your local environmental parameters.