Overview
The JLSW3-10 is a 10 kV class outdoor oil-immersed combined instrument transformer, integrating three single-phase fully-insulated voltage transformers and three electromagnetic current transformers in a single oil-filled enclosure. Designed for three-phase A-B-C systems with Y/Y connection, it provides reliable insulation and thermal performance in outdoor environments.
It supports accuracy classes 0.2 and 0.2S for revenue-grade metering, with additional protection cores available as specified. Typical applications include outdoor substations, industrial power distribution, primary-side metering, and relay protection systems. The unit complies with GB 20840 series standards for combined instrument transformers, current transformers, and voltage transformers.
Key Ratings Snapshot
| Parameter | Rating |
|---|---|
| System voltage class | 10 kV (6 kV variant available) |
| Rated frequency | 50 Hz / 60 Hz |
| Voltage transformer configuration | 3 × single-phase fully-insulated PT, Y/Y connected |
| Current transformer configuration | 3 × electromagnetic CT (A, B, C phases) |
| Accuracy classes | 0.2 / 0.2S (metering); protection cores as specified |
| PT/CT transformation ratio | Customizable per order |
| Rated burden | As specified per core/winding (VA) |
| Insulation structure | Oil-immersed with moisture-prevention device |
| Installation environment | Outdoor (substations, industrial distribution) |
| Applicable standards | GB 20840.4-2015, GB 20840.2-2014, GB 20840.3-2013 |
| Lightning protection | Zinc oxide surge arrester required within 1 m |
Model Designation
- J: Combined instrument transformer (metering unit)
- L: Current transformer component included
- S: Voltage transformer (PT) component included
- W: Outdoor installation type
- 3: Three-phase configuration (A-B-C phases)
- 10: Voltage class (kV)
Construction
The JLSW3-10 features a compact square oil tank designed for outdoor service, combining durability with ease of maintenance. The oil-immersed insulation system ensures high dielectric strength and thermal stability, while an integrated moisture-prevention device on the tank cover blocks external humidity ingress. Three single-phase fully-insulated electromagnetic voltage transformers and three electromagnetic current transformers are securely mounted on the tank base plate and enclosed within the oil-filled assembly. The tank cover includes lifting lugs for handling, an oil level gauge for monitoring, a grounding bolt for safety, and a drain valve for servicing. All components are configured for Y/Y three-phase connection across A, B, and C phases, ensuring balanced operation in medium-voltage outdoor distribution systems.
Technical Parameters
Service Conditions
- Installation: Outdoor (substations/industrial sites/primary metering points)
- Altitude: ≤1000 m standard; higher altitude on request
- Temperature: Per GB outdoor oil-immersed limits; extremes to be specified
- Humidity: Outdoor moisture-proof/breather protected
- Site condition: Non-corrosive, non-explosive, low vibration/impact
- Lightning: ZnO arrester required within 1 m of the unit
Technical Parameters
The JLSW3-10 is a 10 kV class outdoor oil-immersed three-phase combined instrument transformer for 50/60 Hz AC systems. It features electromagnetic CTs and single-phase PTs in Y/Y configuration, with customizable transformation ratios, accuracy classes up to 0.2/0.2S, and rated burdens per secondary winding. Designed for altitudes up to 1000 m and compliant with GB 20840 series standards, it supports primary current ranges as specified at ordering.
Model Variants
| Parameter | JLSW3-6 | JLSW3-10 |
|---|---|---|
| System voltage class | 6 kV | 10 kV |
| Rated frequency | 50 / 60(Hz) | 50 / 60(Hz) |
| PT configuration | 3 × single-phase, Y/Y connection | 3 × single-phase, Y/Y connection |
| CT configuration | 3 × electromagnetic type | 3 × electromagnetic type |
| Metering accuracy class | 0.2 / 0.2S | 0.2 / 0.2S |
| PT transformation ratio | Per specification (customizable) | Per specification (customizable) |
| CT transformation ratio | Per specification (customizable) | Per specification (customizable) |
| Secondary output (PT) | Per specification (VA) | Per specification (VA) |
| Secondary output (CT) | Per specification (VA) | Per specification (VA) |
| Insulation structure | Oil-immersed with moisture prevention | Oil-immersed with moisture prevention |
| Installation | Outdoor | Outdoor |
Installation & Wiring
Installation Diagram
The JLSW3-10 10kV outdoor oil-immersed combined instrument transformer shall be installed in accordance with the dimensional drawing provided. Secure mounting must be performed using the designated base provisions to ensure mechanical stability. Primary connections for both the potential transformer (PT) and current transformer (CT) must follow the terminal markings and connection diagram. Maintain adequate clearance around the unit for insulation, heat dissipation, oil level monitoring, and maintenance access. A zinc oxide surge arrester must be installed within 1 meter of the transformer for effective lightning protection.
Selection & FAQs
Selection Guide
- Select the 6kV or 10kV version and confirm the three-phase Y/Y metering connection and system grounding.
- Specify VT and CT ratios, secondary outputs, number of cores, and terminal allocation.
- Choose class 0.2 or 0.2S and calculate the connected burden for every secondary winding.
- Confirm altitude, pollution, temperature, lightning protection, and any protection-core requirement.
- Verify certified dimensions, foundation, terminal clearances, grounding, oil inspection access, and arrester placement.
Frequently Asked Questions
Q1: Which accuracy class is available for this combined transformer?
Accuracy classes up to 0.2/0.2S are available for the instrument windings. Specify your exact transformation ratio and rated burden during ordering. Factory calibration is provided.
Q2: Can this oil-immersed transformer be installed at high altitudes?
Standard models are designed for altitudes up to 1000 meters. For installations above 1000 meters, custom derating and design modifications are subject to factory confirmation.
Q3: What surge protection is required during outdoor installation?
A ZnO surge arrester must be installed within 1 meter of the unit. Ensure the site is non-corrosive and verify low vibration conditions before installation.
Q4: How are primary current ranges customized for specific projects?
Primary current ranges are customized based on your specific project requirements at the time of ordering. Contact our sales team with your single-line diagram for exact ratio selection.
Q5: Which international standards does this 10kV combined transformer comply with?
The JLSW3-10 is fully compliant with the GB 20840 series standards. For specific IEC or IEEE certification requirements, please contact us for detailed compliance documentation.
Q6: What are the primary applications for the JLSW3-10 unit?
This 10kV outdoor combined instrument transformer is primarily used in substations and industrial sites. It integrates electromagnetic CTs and single-phase PTs. Consult our engineers for specific layout requirements.
Q7: Are there different voltage variants available from this manufacturer?
Yes, the JLSW3 series includes both 6 kV and 10 kV models. Specify your required system voltage class when requesting a formal quotation from our team.