Overview
The JLS-35KV is an outdoor oil-immersed three-phase combined instrument transformer designed for 35 kV-class metering applications. It integrates two single-phase fully-insulated voltage transformers (VTs) and two current transformers (CTs) within a sealed, oil-filled enclosure, providing robust electrical insulation and environmental protection.
Offering accuracy classes of 0.2 / 0.2S for both voltage and current metering cores, the JLS-35KV supports revenue-grade energy measurement in rural distribution networks, industrial facilities, and compact outdoor substations. The unit complies with GB 20840 series standards for combined instrument transformers, ensuring reliable performance under harsh outdoor conditions.
Key Ratings Snapshot
| Parameter | Rating |
|---|---|
| System voltage class | 35 kV |
| Rated frequency | 50 Hz / 60 Hz |
| Configuration | 2 × VTs (V/V) + 2 × CTs |
| Voltage transformer connection | V/V (open delta) |
| Current transformer installation | Series in phases A and C |
| Accuracy classes | 0.2 / 0.2S |
| Insulation type | Oil-immersed, fully-insulated windings |
| Installation environment | Outdoor |
| Moisture protection | Enhanced barrier on tank cover |
| Applicable standards | GB 20840.4-2015, GB 20840.2-2014, GB 20840.3-2013 |
| Lightning protection | Surge arrester required within 1 m |
Model Designation
- J: Combined instrument transformer (voltage + current)
- L: Current transformer component designation
- S: Oil-immersed (liquid-insulated) construction
- 35: Voltage class (kV)
Construction
The JLS-35 features a compact rectangular oil tank constructed from high-quality steel with a weatherproof, corrosion-resistant coating suitable for outdoor service. Inside the sealed enclosure, two single-phase electromagnetic voltage transformers and two electromagnetic current transformers—either toroidal or wound-core—are securely mounted on an internal frame. All components are immersed in high-quality transformer oil, which provides dielectric insulation, thermal management, and environmental sealing.
The tank includes a seamless cover with lifting lugs, an oil level sight glass, an external grounding terminal, and an oil drain valve for maintenance. An enhanced moisture barrier on the tank cover prevents atmospheric humidity ingress, ensuring long-term reliability. Secondary terminals exit through insulated bushings, with markings compliant with GB 20840 polarity and phasing conventions.
Technical Parameters
Service Conditions
- Installation environment: Outdoor installation with direct weather exposure
- Altitude: Not exceeding 1000 m above sea level (higher altitude applications require engineering confirmation and possible derating)
- Ambient temperature: −25 °C to +40 °C (oil viscosity and insulation properties maintained across this range)
- Relative humidity: Daily average ≤ 95%, monthly average ≤ 90%
- Pollution level: Suitable for light to moderate pollution environments; heavy pollution areas may require enhanced external insulation
- Seismic conditions: Installations in seismic zones shall be confirmed during engineering design phase
- Environmental conditions: No corrosive gases or vapors that degrade oil or tank materials; no explosive atmosphere
Technical Parameters
The JLS-35 is a 35 kV class outdoor oil-immersed three-phase combined instrument transformer, integrating voltage and current transformers in a single unit. It operates within an ambient temperature range of −25 °C to +40 °C and is rated for altitudes up to 1000 m. The device complies with standard utility requirements for rural grid, outdoor substation, and industrial metering applications, supporting primary current ranges from 5 A to 1500 A.
Voltage Transformer Data
| Primary Voltage (kV) |
Secondary Voltage (V) |
Accuracy Class |
Burden (VA) |
Connection Type |
|---|---|---|---|---|
| 35 / √3 | 100 / √3 | 0.2 / 0.2S | 25 – 100 VA (per core) | V/V (two single-phase units) |
| 35 / √3 | 100 | 0.2 / 0.2S | 25 – 100 VA (per core) | Line-to-neutral equivalent (V/V configuration) |
| Other voltage ratios available upon request and engineering confirmation | ||||
Current Transformer Data
| Primary Current |
Secondary Current |
Accuracy Class |
Burden (VA) |
Installation Location |
|---|---|---|---|---|
| 5 – 1500 A | 1 A / 5 A | 0.2 / 0.2S | 2.5 – 20 VA (per core) | Phases A and C |
| Specific ratio and burden combinations subject to engineering confirmation | ||||
Installation & Wiring
Installation Diagram
The JLS-35KV transformer is designed for outdoor pole or platform mounting. It must be securely fastened to a level concrete foundation or steel structure using the provided mounting holes. Ensure proper alignment of primary and secondary terminals during installation to facilitate safe and reliable connections.
Selection & FAQs
Selection Guide
- Confirm the 35kV three-phase three-wire network and verify the V/V metering connection.
- Specify VT ratio and burden, then select the 5A–1500A CT ratio and 1A or 5A secondary.
- Choose class 0.2 or 0.2S and calculate the complete burden of each metering circuit.
- Confirm altitude, pollution, temperature, external insulation, lightning, and seismic requirements.
- Verify foundation, terminal arrangement, clearances, oil service access, grounding, lifting, and surge arrester location.
Frequently Asked Questions
Q1: What applications suit the JLS-35 combined transformer?
It is designed for rural grids, outdoor substations, and industrial metering applications. It integrates 35 kV voltage and current transformation with primary currents up to 1500 A. Contact our engineering team for specific project sizing.
Q2: Can this 35kV transformer operate in high humidity environments?
Yes, it supports daily average humidity up to 95% and monthly averages up to 90%. Ensure the installation environment lacks corrosive gases or explosive atmospheres. Confirm specific site conditions during the design phase.
Q3: How does altitude affect the JLS-35 oil-immersed transformer?
Standard ratings apply for altitudes not exceeding 1000 meters above sea level. For higher altitude applications, engineering confirmation and possible derating are required. Please provide your exact site elevation for factory evaluation.
Q4: Which primary current ranges are available for this combined unit?
The integrated current transformer supports primary current ranges from 5 A to 1500 A. Specify your exact primary and secondary current requirements during the ordering process. Custom ratios are subject to factory confirmation.
Q5: Are specific factory tests performed before shipment?
Routine testing protocols are applied to verify basic electrical performance. Specific type tests or special requirements are subject to project confirmation. Contact our sales team for detailed test documentation and certification details.
Q6: Is external insulation customizable for heavy pollution areas?
The standard unit suits light to moderate pollution environments. For heavy pollution areas, enhanced external insulation configurations are available. Specify your local pollution level to receive a customized engineering proposal.
Q7: Who manufactures this 35kV outdoor combined instrument transformer?
It is produced by specialized instrument transformer manufacturers adhering to standard utility requirements. The unit integrates voltage and current transformation for outdoor substations. Contact us for OEM inquiries and manufacturer certifications.