Overview
The JLSZY-10 and JLSZY-6 are three-phase dry-type combined instrument transformers designed for accurate energy metering and protection in 6 kV and 10 kV outdoor medium-voltage distribution systems. These oil-free units integrate three single-phase voltage transformers in Y/Yo configuration with current transformers embedded in A-phase and C-phase, delivering simultaneous voltage and current transformation in a compact, maintenance-free package ideal for urban and rural grid applications.
Featuring fully insulated epoxy resin cast construction, the JLSZY series ensures reliable operation under harsh outdoor conditions while eliminating environmental risks associated with oil-filled alternatives. Its integrated design reduces installation footprint, simplifies wiring, and supports flexible secondary output selection to match diverse metering and protection requirements.
Key Ratings Snapshot
| Parameter | Value |
|---|---|
| System voltage class | 6 kV / 10 kV |
| Rated frequency | 50 Hz (60 Hz on request) |
| VT secondary voltage | 100 V (three-phase) |
| CT secondary current | 5 A, 2 A, or 1 A (adjustable via taps) |
| VT accuracy classes | 0.2 class: 3 x 15 VA; 0.5 class: 3 x 30 VA |
| Insulation level (Um/Ud/Up) | 1.2/42/75 kV |
| Minimum creepage distance | 440 mm |
| CT short-circuit withstand | Ith (1 s) and Idyn (peak) per ratio |
| Ambient temperature range | -25 deg C to +40 deg C |
| Mounting type | Post-type (support) |
Model Designation
- J: Combined instrument transformer (VT + CT integrated)
- L: Current transformer portion
- S: Three-phase configuration
- Z: Support (post) type installation
- Y: Voltage transformer (VT) portion included
- 6 / 10: Voltage class (kV)
Construction
The JLSZY series features a fully enclosed dry-type design with high-strength epoxy resin casting that provides superior insulation, moisture resistance, and pollution resistance. The three-phase integrated structure houses three single-phase VTs in Y/Yo connection and CTs embedded in A-phase and C-phase, all within a single weather-resistant shell. This oil-free construction eliminates maintenance tasks such as oil sampling or replacement, ensuring long-term reliability with only periodic surface cleaning required.
Terminal markings follow standard polarity conventions, with clearly labeled primary (A/B/C/N) and secondary (a/b/c/n for VT; 1K1/1K2 and 2K1/2K2 for CTs) connections. Internal adjustable taps allow selection of 5 A, 2 A, or 1 A secondary current output during commissioning to optimize compatibility with connected metering and protection devices.
Technical Parameters
Service Conditions
- Installation environment: Outdoor (weather-resistant enclosure)
- Altitude: <= 1000 m above sea level
- Ambient temperature: -25 deg C to +40 deg C
- Relative humidity: Daily average <= 95%, monthly average <= 90%
- Pollution level: Moderate (440 mm minimum creepage distance)
- Seismic resistance: Specify at ordering for high-risk zones
- Environmental restrictions: Free from severe vibration, mechanical shock, explosive or highly corrosive atmospheres
Technical Data
| Rated Primary Current (A) |
Rated Short-time Thermal Current (kA RMS) |
Rated Dynamic Current (kA peak) |
Rated Secondary Output (VA) |
|---|---|---|---|
| 5-10 | 1.0 | 2.5 | 10 |
| 10-20 | 1.5 | 3.75 | 10 |
| 15-30 | 2.4 | 6.0 | 10 |
| 20-40 | 3.0 | 7.5 | 10 |
| 30-60 | 4.5 | 11 | 10 |
| 40-75 | 8.0 | 20 | 10 |
| 50-100 | 9.0 | 22.5 | 10 |
| 75-150 | 12 | 30 | 10 |
| 100-200 | 16 | 40 | 10 |
| 150-300 | 24 | 60 | 10 |
| 200-400 | 32 | 80 | 10 |
| 300-600 | 60 | 100 | 10 |
| 400-800 | 80 | 100 | 10 |
| 500-1000 | 80 | 100 | 10 |
Installation & Wiring
Installation Diagram
The JLSZY-10 combined transformer is designed for secure post-type mounting on stable outdoor structures. Primary connections are made via overhead lines or busbars to terminals A, B, C, and N. Secondary wiring must be routed through weatherproof conduit to metering and protection panels, with proper grounding applied at one point per circuit. Adequate clearance around the unit is essential for insulation integrity, heat dissipation, and maintenance access.
Outline Dimensions
| Dimension | Value (mm) |
|---|---|
| Total height | Refer to dimensional drawing |
| Base mounting hole pattern | Refer to dimensional drawing |
| Creepage distance | 440 |
| Weight | Refer to nameplate |
Selection & FAQs
Selection Guide
- Select JLSZY-6 for 6 kV systems or JLSZY-10 for 10 kV systems based on nominal system voltage.
- Choose CT rated primary current to match expected load range; refer to technical data table for short-circuit withstand capability.
- Specify VT accuracy class (0.2 for precision metering, 0.5 for general use) and corresponding burden (15 VA or 30 VA per phase).
- Confirm CT secondary current requirement (5 A, 2 A, or 1 A) and configure internal taps during commissioning.
- For installations above 1000 m altitude, in high-pollution areas, or seismic zones, provide environmental details at ordering stage.
- Ensure secondary wiring complies with grounding and protection standardsâfuse VT outputs and never leave CT secondaries open.
Frequently Asked Questions
Q1: Can this outdoor combined transformer be installed at high altitudes?
Yes, it is suitable for standard elevations. The unit is designed for altitudes up to 1000 meters above sea level. Specify your exact site elevation during ordering for custom adjustments.
Q2: What is the maximum short-circuit thermal current rating?
It reaches up to 9.0 kA RMS. The rated short-time thermal current ranges from 1.0 kA to 9.0 kA depending on the primary current selected. Contact us with your system fault levels for precise selection.
Q3: How to order for high seismic risk zones?
Custom reinforcement is available. Standard models meet basic requirements, but high-risk zone specifications must be explicitly stated at the time of ordering. Confirm your local seismic parameters with our engineering team.
Q4: Which pollution level does the weather-resistant enclosure support?
It supports moderate pollution environments. The design features a minimum creepage distance of 440 mm to handle daily average humidity up to 95%. Ensure the installation site is free from highly corrosive atmospheres.
Q5: What secondary output is standard for this transformer?
The standard rated secondary output is 10 VA. This applies across all primary current ranges from 5A to 100A. Custom burdens are subject to confirmation during the design phase.
Q6: Where is this three-phase dry-type transformer typically applied?
It is used in outdoor power distribution networks. The JLSZY-10 model integrates voltage and current transformation for 10kV systems in moderate pollution areas. Contact our sales team for regional application guidelines.
Q7: Are you a direct manufacturer of combined transformers?
Yes, we are a direct manufacturer. We produce the JLSZY-10 three-phase dry-type outdoor combined transformer with in-house assembly and testing. Request our factory profile and quality management details for verification.