Overview
The JLS-33/35 is an outdoor oil-immersed combined transformer metering box designed for 33kV and 35kV high-voltage power systems. It integrates both current transformer (CT) and voltage transformer (PT) functions into a single three-phase two-component assembly, utilizing high-quality transformer oil for insulation and cooling, with porcelain bushings for reliable high-voltage performance.
This metering device delivers accurate active and reactive energy measurement suitable for utility revenue billing and industrial high-current applications. It complies with GB/T201-2006 standards and supports dual voltage ratios (33000/110V and 35000/100V), accommodating load currents from 5A up to 1200A across two weight variants.
Key Ratings Snapshot
| Parameter | Rating |
|---|---|
| Voltage Class | 33kV / 35kV |
| System Frequency | 50Hz |
| Current Range | 5A – 1200A |
| Voltage Ratios | 33000/110V, 35000/100V |
| Insulation Type | Oil-immersed |
| Phase Configuration | Three-phase two-component |
| Accuracy Class (Metering) | 0.2 / 0.5 |
| Ambient Temperature Range | -15°C to +55°C |
| Weight (Low Current) | 365kg (≤300A) |
| Weight (High Current) | 428kg (400–1200A) |
| Bushing Material | Porcelain |
| Applicable Standard | GB/T201-2006 |
Model Designation
- J: Combined instrument transformer (CT + PT)
- L: Outdoor installation type
- S: Three-phase two-component configuration
- 33/35: Rated system voltages of 33kV and 35kV
Construction
The JLS-33/35 features a robust oil-immersed construction with a sealed tank filled with high-grade transformer oil, providing both electrical insulation and efficient heat dissipation. The core components—current and voltage transformers—are integrated within a single housing, eliminating the need for separate CT and PT units. Porcelain bushings are used for all high-voltage connections, ensuring long-term reliability in outdoor environments. The three-phase two-component layout connects phases A and C for measurement, with phase B serving as the common reference. The enclosure is designed for direct mounting on outdoor substation structures, with provisions for secure anchoring and cable termination.
Technical Parameters
Service Conditions
- Installation position: Outdoor substation or distribution points on transformer high-voltage side
- Ambient temperature: -15°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 JLS-33/35 is an outdoor oil-immersed combined transformer metering box designed for 33kV and 35kV systems. It features oil-immersed insulation with porcelain bushings, operates within a temperature range of -15°C to +55°C, and is suitable for installations up to 4500m altitude without derating. Compliant with GB/T201-2006, it supports current ranges from 5A to 1200A.
Model Variants
| Specification | Current Range | Weight | Dimensions (W) | Application |
|---|---|---|---|---|
| Standard | 5 – 300A | 365 kg | 1300 ± 10mm | Medium current applications |
| Heavy-duty | 400 – 1200A | 428 kg | 1530 ± 10mm | High current industrial applications |
Voltage Transformer Data
| Rated Voltage (V) |
Accuracy Class |
Rated Output (VA) |
Insulation Level (kV) |
|---|---|---|---|
| 33000/110 | 0.2 | 40 | 40.5/95/185 |
| 35000/100 | 0.5 | 60 |
Current Transformer Data
| Current Ratio (A) |
Accuracy Class |
Rated Output (VA) |
Short-Time Thermal Current |
Dynamic Current |
Insulation Level (kV) |
|---|---|---|---|---|---|
| 5 – 300/5 | 0.2S | 15 | 80 × I1n | 200 × I1n | 40.5/95/185 |
| 5 – 300/5 | 0.2 | 15 | 80 × I1n | 200 × I1n | |
| 5 – 300/5 | 0.5 | 20 | 80 × I1n | 200 × I1n |
Installation & Wiring
Installation Diagram
The JLS-33/35 oil-immersed combined transformer metering box is designed for pole-mounted or platform installation on the high-voltage side of power supply transformers. Ensure adequate clearance and secure mounting according to local structural requirements. The standard version (365kg) uses three insulators with a center vertical and outer angled configuration, while the heavy-duty variant (428kg) features reinforced construction suitable for high-current applications.
Wiring Diagram
Wiring connections must follow the approved project diagram. The device includes both current transformers (CTs) and voltage transformers (PTs):
- AP1/AP2/AP3 terminals correspond to the primary windings of the PTs.
- CP1/CP2/CP3 terminals correspond to the primary windings of the CTs.
- PT secondary terminals supply voltage input to meters and monitoring equipment.
- CT secondary terminals provide current input to active and reactive energy meters.
Always verify terminal sequence before commissioning. CT secondary circuits must never be left open during operation to prevent hazardous overvoltages.
Selection & FAQs
Selection Guide
- Select the 33kV or 35kV voltage ratio and verify the two-component three-phase metering scheme.
- Choose the 5A–1200A current configuration and standard or heavy-duty structure from the load profile.
- Specify accuracy class, rated output, CT and PT burdens, and meter requirements.
- Confirm altitude, temperature, pollution, porcelain creepage, oil, grounding, lightning, and site conditions.
- Verify the 365kg or 428kg support load, width, clearances, terminal sequence, oil access, and drawing.
Frequently Asked Questions
Q1: Can the JLS-33/35 be installed at high altitudes?
Yes, it operates up to 4500m altitude without derating. It features oil-immersed insulation with porcelain bushings for outdoor substations. Confirm specific site conditions with our engineering team.
Q2: Which model variant supports currents above 300A?
Select the heavy-duty variant for 400A to 1200A applications. It weighs 428 kg with a width of 1530 ± 10mm. Contact sales for detailed dimensional drawings.
Q3: What ambient temperature range does this transformer support?
It operates reliably across a wide climate range. The unit functions between -15°C and +55°C using high-quality transformer oil for outdoor insulation. Verify local temperature extremes during your project design phase.
Q4: Are these combined transformers compliant with GB/T201-2006?
Yes, they are fully compliant with GB/T201-2006 standards. The design supports 33kV and 35kV outdoor metering systems with current ranges from 5A to 1200A. Request the official compliance certificate from your account manager.
Q5: How long is the lead time for custom orders?
Lead times depend on your specific configuration. Standard models ship per regular schedules, while custom ratios are subject to confirmation. Contact procurement for exact delivery timelines.
Q6: Why choose an oil-immersed combined transformer for metering?
It is ideal for high-voltage outdoor metering. The unit integrates current and voltage measurement with oil-immersed insulation for 33kV and 35kV substations. Contact us for application engineering support.
Q7: When should periodic oil maintenance be performed?
Maintenance should align with your substation’s scheduled outages. Perform periodic oil level checks and quality inspections while verifying grounding per local codes. Request the detailed maintenance manual from your supplier.