Overview
The JLSZY-10 and JLSZY-6 are three-phase combined instrument transformers rated for 10 kV and 6 kV medium-voltage outdoor distribution systems, respectively. They feature a dry-type, oil-free design with epoxy resin cast insulation, integrating both current transformers (CT) and voltage transformers (VT) in a single compact unit.
These units deliver high measurement accuracy—VT accuracy classes of 0.2 (3 × 15 VA) and 0.5 (3 × 30 VA)—making them suitable for precision energy metering and protection applications. They comply with IEC 61869 and GB/T 20840 series standards and are widely deployed in outdoor substations, industrial facilities, and grid modernization projects requiring maintenance-free, pollution-resistant instrumentation.
Key Ratings Snapshot
| Parameter | Rating |
|---|---|
| System voltage class | 6 kV / 10 kV |
| Rated frequency | 50 Hz (60 Hz optional) |
| Secondary current (CT) | 5 A, 2 A, or 1 A (tapped) |
| Secondary voltage (VT) | 100 V (three-phase) |
| VT accuracy classes | 0.2 class: 3 × 15 VA; 0.5 class: 3 × 30 VA |
| CT short-circuit withstand | Ith (1 s) and Idyn (peak) per ratio |
| Insulation level (Um/Ud/Up) | 1.2/42/75 kV |
| Minimum creepage distance | 440 mm |
| Applicable standards | IEC 61869-1/-2/-3; GB/T 20840.1/.2/.3; GB 1207; GB 1208 |
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: System voltage class in kV
Construction
The JLSZY-6 and JLSZY-10 feature a three-phase combined VT+CT structure with outdoor post-type mounting. The core insulation system is fully enclosed dry-type epoxy resin cast, eliminating oil and enabling maintenance-free operation. Three single-phase voltage transformers are connected in Y/Yo configuration, delivering a standardized 100 V secondary output. Current transformers are embedded in the A-phase and C-phase, each equipped with internal adjustable taps for secondary current selection (5 A, 2 A, or 1 A). The housing is molded from high-strength, weather-resistant epoxy resin with UV and aging resistance, ensuring reliable long-term outdoor performance under polluted and humid conditions.
Technical Parameters
Service Conditions
- Installation environment: Outdoor installation (weather-resistant enclosure)
- Altitude: Not exceeding 1000 m above sea level (higher altitude applications require engineering confirmation)
- Ambient temperature: −25 °C to +40 °C
- Relative humidity: Daily average ≤ 95%, monthly average ≤ 90%
- Pollution level: Designed for moderate pollution environments with 440 mm minimum creepage distance
- Seismic resistance: Specify seismic requirements at ordering stage for high-risk zones
- Environmental conditions: Free from severe vibration, mechanical shock, explosive or highly corrosive atmospheres
Technical Parameters
The JLSZY-6/10 is a three-phase cast-resin combined instrument transformer for 6 kV and 10 kV AC systems (50 Hz), featuring epoxy resin insulation and outdoor-rated construction. It operates within an ambient temperature range of −25 °C to +40 °C and is suitable for installations up to 1000 m altitude. The unit supports primary current ranges from 5 A to 1000 A and complies with standard insulation levels for medium-voltage applications.
Voltage transformer Data
| Rated voltage ratio(V) |
Accuracy classes |
Rated output(VA) |
Rated insulation level(kV) |
|---|---|---|---|
| 6000/√3:100/√3:100/3 | 0.2 | 30 | 7.2/32/60 |
| 10000/√3:100/√3:100/3 | 0.5 | 40 | 12/40/75 |
| 11000/√3:110/√3:110/3 | 60 |
Current transformer Data
| Rated currentratio(A) |
Accuracy classes |
Rated output(vA) |
Rated short-time thermal current (Ith) |
Rated
dynamic |
Rated insulation level(kV) |
|---|---|---|---|---|---|
| 5~300/5 | 0.2S | 15 | 60I1n | 150I1n | 12/42/75 |
| 0.2 | 15 | ||||
| 0.5 | 20 |
Installation & Wiring
Outline Dimensions
The outline drawings provide critical dimensional data including overall height, width, depth, and locations of mounting holes for the JLSZY-10 and JLSZY-6 three-phase combined instrument transformers. These dimensions must be referenced to ensure proper fitment and alignment during installation on poles, platforms, or substation structures.
Selection & FAQs
Selection Guide
- Select the correct model designation (JLSZY-6 for 6 kV systems or JLSZY-10 for 10 kV systems) based on your network voltage class.
- Specify CT parameters including rated primary current, transformation ratio (for A-phase and C-phase), secondary current (5 A, 2 A, or 1 A), accuracy class, burden (VA), and short-circuit withstand capabilities (Ith and Idyn).
- Define VT requirements such as accuracy class (0.2 or 0.5) and rated burden per phase (15 VA or 30 VA).
- Confirm environmental conditions including installation altitude (above 1000 m if applicable), pollution level, seismic requirements, and ambient temperature range beyond standard limits.
- Indicate any customization needs like enhanced creepage distance for pollution resistance, special mounting or terminal configurations, or additional accessories such as power modules or upgraded enclosures.
Frequently Asked Questions
Q1: Can this combined transformer be installed at high altitudes?
Standard models are rated for altitudes up to 1000 m above sea level. For higher elevation projects, engineering confirmation is required to adjust insulation parameters. Contact our technical team for details.
Q2: What primary current ranges are available for the JLSZY-10?
The JLSZY-10 supports primary current ranges from 5 A to 1000 A for 10 kV AC systems. Specify your exact primary and secondary current requirements during the ordering stage for proper core selection.
Q3: Why must seismic requirements be specified at the ordering stage?
Standard units are designed for environments free from severe vibration and mechanical shock. For high-risk seismic zones, you must specify exact seismic resistance requirements at the ordering stage for custom reinforcement.
Q4: Which accuracy classes are offered for the voltage transformer section?
Accuracy classes and rated outputs depend on the specific voltage ratio selected. Please refer to the technical parameter table or contact our engineers to confirm the exact accuracy class suitable for your metering needs.
Q5: Are custom creepage distances available for heavy pollution environments?
The standard design includes a 440 mm minimum creepage distance for moderate pollution environments. For severe pollution conditions, custom creepage distances can be engineered. Please provide site pollution levels for factory evaluation.
Q6: How are routine factory tests handled before shipment?
Standard factory compliance documentation is provided with every unit. If your project requires specific third-party certifications or special witness testing, these must be confirmed during the initial inquiry. Contact our sales team for details.
Q7: Where is the JLSZY-6 combined transformer typically applied?
It is designed for 6 kV and 10 kV outdoor AC power systems to provide simultaneous current and voltage measurement. The weather-resistant epoxy resin enclosure ensures reliable operation in moderate pollution environments.