Overview
The JLS-6, JLSZV-10, and JLS-10 series are outdoor oil-immersed combined instrument transformers that integrate current transformers (CT) and voltage transformers (VT/PT) into a single sealed enclosure. Designed for 6 kV and 10 kV AC distribution systems, these units deliver galvanically isolated secondary signals for precise active and reactive energy metering using a three-phase V/V connection configuration.
Featuring electromagnetic CTs with toroidal cores and conventional wound VTs, the design ensures high accuracy, long service life, and reliable performance in harsh outdoor environments. The oil-immersed construction provides excellent insulation, thermal stability, and protection against moisture and contamination.
Key Ratings Snapshot
| Parameter | Value |
|---|---|
| System voltage class | 6 kV or 10 kV |
| Rated frequency | 50 Hz or 60 Hz |
| Configuration | 3-phase V/V: 2x VT + 2x CT |
| Accuracy class | 0.2 or 0.2S (metering grade) |
| Insulation medium | Oil-immersed with moisture-proof device |
| Application | Active and reactive energy metering |
| Installation environment | Outdoor (pole or platform mounted) |
| Overvoltage protection | Zinc oxide surge arrester within 1 m |
| Structural features | Compact, lightweight, high capacity |
| Secondary output | Per nameplate designation |
Model Designation
- J: Combined (integrated) transformer
- L: Current transformer component
- S: Three-phase configuration
- 6, 10: Voltage class in kV
Construction
The transformer features a rectangular, sealed oil-filled tank with integrated moisture-proof breathing device, lifting lugs, oil level indicator, grounding bolt, and drain valve. All internal componentsâtwo single-phase VTs and two CTsâare mounted on insulated supports within the tank, with terminals brought out through sealed bushings. This design ensures superior insulation performance, effective thermal management, and resistance to environmental ingress.
The oil-immersed construction enhances dielectric strength and heat dissipation, making it ideal for continuous outdoor operation in rural, industrial, and substation applications. Complete sealing and the moisture-proof device significantly extend service life compared to conventional dry-type alternatives.
Technical Parameters
Service Conditions
- Installation environment: Outdoor (pole-mounted or platform-mounted)
- Altitude: <= 1000 m above sea level (higher altitude requires engineering confirmation)
- Ambient temperature: Consult factory for location-specific requirements
- Pollution level: Specify severity for external insulation selection
- Environmental exposure: Designed for outdoor use with moisture-proof protection
Technical Data
| Voltage Class (kV) |
VT Ratio (Primary/Secondary) |
CT Ratio (Primary/Secondary) |
Accuracy Class (CT & VT) |
Secondary Output (VA) |
|---|---|---|---|---|
| 6 or 10 | As per order | As per order | 0.2 or 0.2S | As per project spec |
Installation & Wiring
Installation Diagram
The transformer must be securely mounted using designated brackets on poles or platforms. Primary connections are made via high-voltage bushings, and secondary circuits must follow standard polarity markings for V/V configuration. A zinc oxide surge arrester must be installed within 1 meter of the unit for overvoltage protection. Before energization, remove the breather plug from the moisture-proof device to activate its function.
Outline Dimensions
| Dimension | Value (mm) |
|---|---|
| Height | As per drawing |
| Width | As per drawing |
| Depth | As per drawing |
| Mounting hole spacing | As per drawing |
| Oil fill volume | As per model |
Selection & FAQs
Selection Guide
- Confirm system voltage (6 kV or 10 kV) and frequency (50/60 Hz) before selection.
- Specify CT and VT ratios based on load current and metering requirements.
- Select accuracy class 0.2S for revenue-grade metering; 0.2 for general precision applications.
- Define ambient conditions: altitude, temperature range, and pollution level for proper insulation rating.
- Ensure installation includes a zinc oxide surge arrester within 1 m of the transformer.
- Request dimensional drawings early to verify mounting compatibility and clearance.
Frequently Asked Questions
Q1: Which accuracy class is suitable for revenue metering?
The 0.2S accuracy class is recommended for revenue billing. It ensures high precision across varying load conditions. Confirm your specific secondary burden requirements with our engineering team.
Q2: Can this combined transformer be installed at high altitudes?
Standard models are rated for altitudes up to 1000 meters above sea level. For installations exceeding this limit, engineering confirmation is required to adjust insulation parameters.
Q3: How do I specify the voltage and current ratios?
Ratios are fully customized as per your project order. Provide your exact primary and secondary voltage and current requirements. Contact our engineers for burden calculation and wiring verification.
Q4: Why must I specify the pollution level for outdoor installation?
Specifying the local pollution severity ensures correct external insulation selection. The unit features moisture-proof protection for standard outdoor environments. Consult the factory for severe environmental conditions.
Q5: Are physical dimensions customizable for restricted switchgear spaces?
Yes, physical dimensions can be customized to fit specific spatial constraints. Provide your maximum allowable footprint and height. Contact our sales team for project-specific dimensional drawings.
Q6: What routine factory tests are performed before shipment?
Standard routine tests are conducted prior to dispatch to ensure compliance. Detailed test reports and specific certification documents are subject to confirmation. Contact us for the exact testing scope.
Q7: When is this 10kV combined transformer typically applied?
It is primarily used in outdoor 6kV or 10kV distribution networks for metering and protection. The unit is available in both pole-mounted and platform-mounted configurations. Ensure the voltage class matches your specific grid application.