Overview
The JLSZW-6 and JLSZW-10 series are three-phase dry-type combined instrument transformers designed for outdoor medium-voltage AC distribution systems. These units integrate voltage and current measurement functions into a single compact, galvanically isolated assembly, delivering standardized secondary signals for accurate energy metering, monitoring, and supervisory control applications.
Engineered with epoxy resin vacuum-cast construction, the transformers offer superior environmental durability, moisture resistance, and long-term reliability in harsh outdoor conditions across urban, rural, and industrial power networks.
Key Ratings Snapshot
| Parameter | Value |
|---|---|
| System voltage class | 6 kV (JLSZW-6) / 10 kV (JLSZW-10) |
| Rated frequency | 50 Hz (60 Hz on request) |
| VT configuration | Two single-phase VTs in V/V connection |
| CT configuration | CTs on phase A and phase C |
| VT secondary voltage | 100 V line-to-line |
| VT output (Class 0.2) | 2 x 15 VA |
| VT output (Class 0.5) | 2 x 30 VA |
| CT secondary current | 5 A, 2 A, or 1 A |
| CT accuracy classes | 0.2, 0.2S, 0.5 (metering/protection) |
| Insulation level (JLSZW-10) | 12/42/75 kV (Um/Up/Ud) |
Model Designation
- J: Voltage transformer (VT) function included
- L: Current transformer (CT) function included
- S: Three-phase configuration
- Z: Support (pillar) type mounting structure
- W: Outdoor installation type
- 6 / 10: Voltage class in kV
Construction
The transformer features fully-enclosed epoxy resin vacuum-cast construction, ensuring void-free insulation, excellent dielectric stability, and robust resistance to moisture ingress, UV degradation, salt spray, and atmospheric pollution. The high-quality aging-resistant insulating material provides long-term mechanical integrity and anti-pollution performance for reliable outdoor service.
Integrated mounting provisions and tapped secondary windings enhance installation simplicity and metering accuracy. The compact design reduces footprint while supporting pole or platform mounting in outdoor substations and overhead distribution terminals.
Technical Parameters
Service Conditions
- Installation environment: Outdoor, weather-resistant enclosure
- Altitude: <= 1000 m (higher on request with correction)
- Ambient temperature: -25 deg C to +40 deg C
- Relative humidity: Daily avg <= 95%, monthly avg <= 90%
- Environmental exposure: Rain, wind, solar radiation, pollution
- Seismic intensity: <= 7 degrees (higher available on request)
Technical Data
| Rated Primary Current (A) |
Rated Secondary Current |
Accuracy Class (Examples) |
Rated Burden (VA) |
|---|---|---|---|
| 5 to 600 | 5 A | 0.2, 0.2S, 0.5 | 2.5, 5, 10, 15 (as specified) |
| 10 to 600 | 2 A | 0.2, 0.2S, 0.5 | 2.5, 5, 10 (as specified) |
| 10 to 600 | 1 A | 0.2, 0.2S, 0.5 | 1.25, 2.5, 5 (as specified) |
Installation & Wiring
Installation Diagram
Proper installation ensures safety, performance, and compliance with local utility requirements. The combined transformer must be securely mounted using the designated support structure for pole or platform applications. Primary connections are made via overhead line terminals or bolted busbar fittings, with adequate clearance maintained for insulation, heat dissipation, and live-line working distances.
Outline Dimensions
| Dimension | Value (mm) |
|---|---|
| Height | Per factory drawing |
| Width | Per factory drawing |
| Depth | Per factory drawing |
| Phase spacing | As ordered (e.g., 340 mm) |
| Mounting hole pattern | Per ordered configuration |
Selection & FAQs
Selection Guide
- Determine system voltage class (6 kV or 10 kV) to select JLSZW-6 or JLSZW-10.
- Select CT primary current based on feeder/load rating and expected operating range.
- Choose VT and CT accuracy classes (e.g., 0.2, 0.2S, 0.5) per metering or protection needs.
- Calculate total burden (VA) for connected meters, relays, and wiring losses to specify rated output.
- Verify insulation level and creepage distance against pollution severity and altitude.
- Confirm CT short-circuit withstand (Ith/Idyn) matches system fault levels if required.
Frequently Asked Questions
Q1: Which accuracy class is suitable for revenue metering?
Select the 0.2S accuracy class for revenue metering applications. This ensures high precision across varying load conditions. Specify your exact burden requirements during order placement.
Q2: Can this combined transformer operate in high-altitude environments?
Standard models are rated for altitudes up to 1000 meters. For higher elevations, derating corrections are required. Please provide your specific site altitude for factory evaluation.
Q3: What is the insulation level for the JLSZW-10 model?
The insulation level is 12/42/75 kV for Um/Up/Ud respectively. It also features a minimum creepage distance of 440 mm. Confirm specific pollution level requirements with our technical department.
Q4: Are secondary current and burden ratios customizable?
Yes, secondary currents of 5A, 2A, or 1A are available. Rated burdens can be tailored to your specific project needs. Submit your single-line diagram for exact factory configuration.
Q5: What factory tests are performed before shipment?
Detailed testing protocols and type test certificates are subject to confirmation. Please contact our sales team to verify the specific factory test reports available for your project.
Q6: Where is this outdoor combined transformer typically applied?
It is primarily used in outdoor 10kV power distribution networks for simultaneous voltage and current measurement. The weather-resistant enclosure ensures reliable operation in harsh environmental conditions.
Q7: How does the dry-type design benefit outdoor installation?
The dry-type epoxy insulation eliminates oil leakage risks and reduces maintenance requirements. It provides excellent resistance to rain, solar radiation, and temperature variations.