Overview
The JLSY12-35W is an outdoor oil-immersed combined transformer metering box designed for 35kV high-voltage power systems. It integrates current transformers (CTs), voltage transformers (PTs), and a meter box into a single oil-filled assembly, using high-quality transformer oil for insulation and cooling.
This three-phase three-component device delivers 0.2S class accuracy for both active and reactive energy measurement, making it suitable for utility revenue metering, industrial high-voltage supply monitoring, and anti-theft applications. It complies with GB20840.4-2015 and IEC 61869.4:2013 standards and operates reliably in ambient temperatures from -25°C to +55°C.
Key Ratings Snapshot
| Parameter | Rating |
|---|---|
| Voltage Class | 35kV |
| Insulation Level | 40.5/80/200kV |
| Current Range | 5A – 600A |
| Accuracy Class (CT) | 0.2S |
| Accuracy Class (PT) | 0.2 |
| Phase Configuration | Three-phase three-component |
| PT Connection | Star-connected |
| Insulation Type | Oil-immersed |
| Total Weight | 352kg |
| Operating Temperature | -25°C to +55°C |
| Meter Integration | Built-in active/reactive or electronic meters |
| Compliance | GB20840.4-2015, IEC 61869.4:2013 |
Model Designation
- J: Voltage transformer (PT)
- L: Current transformer (CT)
- S: Three-phase combined unit
- Y: Oil-immersed insulation
- 12: Design series number
- 35: Rated voltage (35kV)
- W: Outdoor application
Construction
The JLSY12-35W features a robust welded steel tank filled with high-grade transformer oil, providing both electrical insulation and efficient heat dissipation. The core-and-coil assembly for both CTs and PTs is fully immersed in oil, ensuring stable dielectric performance under continuous high-voltage stress. Porcelain bushings are used for all high-voltage connections, offering excellent creepage distance and weather resistance. The integrated meter compartment is sealed within the same oil-filled enclosure, protecting meters from moisture and contamination while maintaining thermal equilibrium. All terminals are accessible via insulated terminal blocks, and the unit includes oil-level indicators and pressure relief devices for safe outdoor operation.
Technical Parameters
Service Conditions
- Installation position: Outdoor substation or distribution points on transformer high-voltage side
- Ambient temperature: -25°C to +55°C
- Maximum altitude: ≤ 4500m (no derating required)
- Insulation: Oil-immersed with porcelain bushings
- Oil type: High-quality transformer oil
- Grounding: Connect grounding terminal per local electrical codes and metering standards
- Maintenance: Periodic oil level check and oil quality inspection required
Technical Parameters
The JLSY12-35W is an outdoor oil-immersed combined transformer metering box designed for 35kV systems, featuring a three-phase three-component configuration. It operates within a temperature range of -25°C to +55°C and at altitudes up to 4500m without derating. The unit complies with GB20840.4-2015 and IEC 61869.4:2013 standards and supports current ratings from 5A to 600A.
Voltage Transformer Data
| Rated Voltage (kV) |
Insulation Level (kV) |
Accuracy Class | Rated Output (VA) |
Max Output (VA) |
|---|---|---|---|---|
| 35/0.1 | 40.5/80/200 | 0.2 | 3×10 | 3×500 |
Current Transformer Data
| Current Ratio(A) |
Rated Insulation Level (kV) |
Accuracy
Class |
Rated Output (VA) |
Short-Time Thermal Current |
Dynamic Current |
|---|---|---|---|---|---|
| 5 – 600 | 40.5/80/185 | 0.2S | 3×10 | 80 × I1n | 200 × I1n |
Installation & Wiring
Installation Diagram
The JLSY12-35W oil-immersed combined transformer metering box is designed for pole or platform mounting on the high-voltage side of distribution transformers. Ensure adequate clearance around the unit for maintenance access and proper ventilation. The unit features three angled insulators on the front, two vertical side insulators with an air release valve, and six top-mounted insulator positions arranged in a rectangular layout.
Wiring Diagram
Wiring connections must follow the approved project diagram. The high-voltage terminals are labeled AP1/AP2, BP1/BP2, and CP1/CP2 for phases A, B, and C respectively—verify sequence before commissioning. The PT secondary terminals supply voltage signals to meters and monitoring equipment, while the CT secondary terminals provide current inputs to active and reactive energy meters. All CT secondary circuits must remain closed during operation to prevent dangerous overvoltages. Grounding conductors and internal meter box wiring must comply with local codes and the project-specific wiring diagram.
Selection & FAQs
Selection Guide
- Confirm the 35kV system, 40.5kV equipment class, frequency, grounding, and three-phase metering connection.
- Select the 5A–600A CT ratio from the feeder load and verify 0.2S accuracy and 3×10VA output.
- Confirm the 35/0.1kV PT ratio, class 0.2 accuracy, output, and complete secondary burden.
- Define altitude, temperature, pollution, porcelain creepage, oil, lightning, grounding, and seismic requirements.
- Verify the 352kg support load, clearances, terminal sequence, oil and pressure devices, lifting, and drawing.
Frequently Asked Questions
Q1: What is the maximum installation altitude for this 35kV combined transformer?
It operates at altitudes up to 4500m without derating. Designed for outdoor substations with ambient temperatures from -25°C to +55°C. Contact us for higher altitude requirements.
Q2: Which accuracy class does the voltage transformer provide for metering?
The VT provides a 0.2 accuracy class with a rated output of 3×10 VA. This ensures precise metering for 35kV systems. Confirm specific secondary burden requirements with our engineering team.
Q3: How should the grounding terminal be connected during installation?
Connect the grounding terminal strictly according to local electrical codes and metering standards. The unit features oil-immersed insulation with porcelain bushings for secure outdoor operation. Verify grounding specifications with your site engineer.
Q4: What international standards does this oil-immersed transformer comply with?
The JLSY12-35W complies with GB20840.4-2015 and IEC 61869.4:2013 standards. It is a three-phase combined transformer rated for 35kV systems. Request the compliance documents from our sales team during procurement.
Q5: Can the current transformer rating be customized for specific projects?
Yes, it supports current ratings ranging from 5A to 600A. Custom ratios are subject to factory confirmation based on your single-line diagram. Please provide exact parameters for a formal quotation.
Q6: Where is this three-phase combined transformer typically applied?
It is applied in outdoor substations and distribution points on the 35kV high-voltage side. This combined transformer integrates voltage and current metering functions. Browse our product category for related 35kV equipment.
Q7: What maintenance is required for the oil-immersed insulation system?
Periodic oil level checks and oil quality inspections are required. The unit uses high-quality transformer oil to maintain dielectric strength. Refer to the operation manual for detailed maintenance intervals.