Overview
The JLS-6 and JLS-10 are three-phase outdoor oil-immersed combined instrument transformers rated for 6 kV or 10 kV medium-voltage distribution systems. These units integrate current transformers (CT) and voltage transformers (VT) within a single sealed, oil-filled enclosure, utilizing a V/V connection configuration to deliver accurate metering signals.
Designed for revenue-grade active and reactive energy metering, they meet accuracy classes 0.2 or 0.2S and comply with Chinese standards GB 20840.1-2010 through GB 20840.4-2015. Typical applications include rural distribution networks, industrial substations, and modernization projects replacing separate CT/VT installations in outdoor environments.
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 |
| 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-type or platform mounting. It incorporates an integrated moisture-proof breathing device to prevent humidity ingress, ensuring long-term insulation integrity and thermal stability. The tank includes lifting lugs for handling, an oil level indicator, a grounding bolt, and a drain valve. 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 provides robust environmental protection and reliable performance in harsh outdoor conditions.
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. Operating conditions include altitudes up to 1000 m and ambient temperatures per site-specific engineering consultation.
Model Variants
| Type (Ratio) |
Rated Voltage (kV) |
Rated Primary Current (A) |
Rated Secondary Current (A) |
Accuracy Class (Protection/ Measurement) |
Burden (VA) |
|---|---|---|---|---|---|
| JLS-6 | 6 | 5–600 | 1 or 5 | 0.2 / 0.2S | 10–30 |
| JLS-10 | 10 | 5–600 | 1 or 5 | 0.2 / 0.2S | 10–30 |
Voltage Transformer Data
| Type (Ratio) |
Rated Voltage (kV) |
Rated Secondary Voltage (V) |
Rated Output (VA) |
Accuracy Class (Protection/ Measurement) |
Burden (VA) |
|---|---|---|---|---|---|
| JLS-6 / JLS-10 | 6 / 10 | 100 / √3 | 30 | 0.2 | 10–30 |
Current Transformer Data
| Current Range |
Rated Current Ratio (A) |
Rated Secondary Current (A) |
Accuracy Class (Protection/ Measurement) |
Burden (VA) |
Short-Time Thermal Current |
Dynamic Current |
|---|---|---|---|---|---|---|
| 5–600 A | 5/1, 5/5, …, 600/1, 600/5 | 1 or 5 | 0.2S | 10–30 | 25 kA / 1 s | 62.5 kA |
Installation & Wiring
Outline Dimensions
Suitable for 6 kV and 10 kV voltage systems. Specific outline dimensions and mounting hole locations are provided in the dimensional drawing above.
Selection & FAQs
Selection Guide
- Select voltage class based on system requirements: JLS-6 for 6 kV or JLS-10 for 10 kV networks.
- Specify voltage transformer ratio (primary/secondary) and current transformer ratio (rated primary/secondary) according to metering and protection needs.
- Define accuracy class for both CT and VT sections—typically 0.2 or 0.2S—for compliance with local utility standards.
- Confirm secondary output values for both CT and VT to ensure compatibility with connected metering or relay equipment.
- Provide installation environment details including ambient temperature range, altitude, and pollution level to ensure reliable outdoor performance.
Frequently Asked Questions
Q1: What is the primary connection type for these combined transformers?
The JLS-6 and JLS-10 feature a V/V connection for both electromagnetic voltage and current transformers. This configuration is standard for 6 kV and 10 kV AC distribution systems.
Q2: Can these oil-immersed transformers be installed at high altitudes?
Standard models are rated for altitudes not exceeding 1000 m above sea level. For higher elevations, engineering confirmation and specification adjustments are required from the factory.
Q3: Which accuracy classes are supported for metering applications?
These combined instrument transformers support 0.2 and 0.2S measurement accuracy classes. Contact the factory to specify your exact metering requirements during the selection process.
Q4: How do we specify external insulation for polluted environments?
You must specify the exact pollution severity level for your installation site. The factory will then select the appropriate external insulation design based on these conditions.
Q5: What standards do these 6kV and 10kV transformers comply with?
The JLS series fully complies with GB 20840 standards. Please contact our sales team for specific factory test reports and detailed compliance certificates.
Q6: Are these units designed for indoor or outdoor switchgear?
They are specifically designed as three-phase outdoor oil-immersed combined transformers. They are suitable for pole-mounted or platform-mounted installations and include moisture-proof devices.
Q7: What are the available primary current ratings for JLS-6?
The JLS-6 model supports rated primary currents ranging from 5 A to 600 A. Secondary currents can be configured for 1 A or 5 A outputs.