Overview
The JLSZY-35 series is a high-precision outdoor combined instrument transformer integrating voltage (PT) and current (CT) measurement in a single epoxy resin housing. Designed for 35 kV three-phase AC systems at 50 Hz, it delivers galvanically isolated secondary signals for revenue metering, energy monitoring, and relay protection in substations and industrial distribution networks.
This maintenance-free unit eliminates oil-related risks while ensuring reliable performance under harsh outdoor conditions through UV-resistant, pollution-tolerant cast-resin construction suitable for long-term deployment.
Key Ratings Snapshot
| Parameter | Value |
|---|---|
| System Voltage Class | 35 kV |
| Rated Frequency | 50 Hz (60 Hz on request) |
| PT Voltage Ratio | 35000/100 V |
| CT Current Ratio | 5~200/5 A |
| PT Accuracy Class | 0.2 or 0.5 |
| CT Accuracy Class | 0.2S or 0.2 |
| PT Rated Burden | 30 VA (0.2) / 50 VA (0.5) |
| CT Rated Burden | 10 VA |
| Insulation Level (Um/Ud/Up) | 42/95/195 kV |
| Short-Circuit Withstand (CT) | Ith: 100xI1n; Idyn: 2.5xIth |
Model Designation
- J: Combined instrument transformer
- L: Current element (CT component)
- S: Voltage element (PT component: three-phase)
- Z: Cast-resin (epoxy) insulated structure
- Y: Outdoor (hu wai) application type
- 35: Voltage class (kV)
Construction
The JLSZY-35 features a post-type outdoor design with fully enclosed epoxy resin casting that integrates both PT and CT elements into one robust mechanical assembly. The housing offers excellent resistance to UV radiation, moisture ingress, surface contamination, and thermal aging, ensuring stable dielectric performance and mechanical strength over decades of outdoor service.
Maintenance-free operation is achieved through the elimination of oil-filled components, reducing environmental risk and lifecycle costs. Secondary terminals are housed in a weather-sealed compartment with clear polarity markings, and the unit mounts securely to concrete or steel platforms via base fixing holes.
Technical Parameters
Service Conditions
- Installation environment: Outdoor (pole-mounted or platform-mounted)
- Altitude: <= 1000 m (higher altitude requires engineering confirmation)
- Ambient temperature: -25 deg C to +40 deg C
- Relative humidity: Daily average <= 95%, monthly average <= 90%
- Environmental exposure: UV, rain, pollution; no explosive/corrosive atmospheres
- Seismic resistance: <= 8 degrees (Chinese code) or per regional requirement
Technical Data
| Model | Rated Voltage Ratio (V) |
Accuracy Class |
Rated Output (VA) |
Limiting Output (VA) |
Thermal Stability (Ith) |
Dynamic Stability (Idyn) |
Insulation Level (kV) |
|---|---|---|---|---|---|---|---|
| JLSZY-35 | 35000/100 | 0.2 | 30 | 500 | 100 x I1n | 2.5 x Ith | 42/95/195 |
| JLSZY-35 | 35000/100 | 0.5 | 50 | 500 | 100 x I1n | 2.5 x Ith | 42/95/195 |
| JLSZY-35 | 5~200/5 | 0.2S | 10 | – | 100 x I1n | 2.5 x Ith | 42/95/195 |
| JLSZY-35 | 5~200/5 | 0.2 | 10 | – | 100 x I1n | 2.5 x Ith | 42/95/195 |
Installation & Wiring
Installation Diagram
The JLSZY-35 must be securely mounted on a concrete foundation or steel platform using the provided base fixing holes. Primary high-voltage connections are made via outdoor-rated connectors suitable for 35 kV service. Secondary wiring exits through sealed cable glands in the weatherproof terminal compartment. A zinc oxide surge arrester must be installed within 1 meter of the unit for effective lightning protection coordination.
Outline Dimensions
| Dimension | Value (mm) |
|---|---|
| Total Height | 1250 |
| Base Mounting Hole Pattern | 200 x 200 |
| Bolt Hole Diameter | phi 18 |
| Primary Terminal Height | 1100 |
| Secondary Compartment Size | 200 x 150 x 100 |
Selection & FAQs
Selection Guide
- Determine PT ratio based on system nominal voltage (typically 35000/100 V for 35 kV networks).
- Select CT primary current rating according to feeder load and expected operating range (5~200 A standard).
- Choose accuracy classes: 0.2S/0.2 for revenue metering; 0.5 for general monitoring.
- Verify total secondary burden (meters + relays + cable losses) does not exceed rated VA.
- Confirm CT short-circuit withstand (Ith/Idyn) exceeds system fault level.
- Specify non-standard conditions (altitude >1000 m, extreme temperature, heavy pollution) during ordering.
Frequently Asked Questions
Q1: Which accuracy class is required for revenue metering?
Select the 0.2S accuracy class for revenue billing applications. It provides a 10 VA rated output and ensures high precision across varying load conditions. Contact our engineering team for specific ratio configurations.
Q2: Can this 35kV combined transformer operate in high-altitude areas?
Standard models are rated for altitudes up to 1000 meters. For installations exceeding this elevation, engineering confirmation is required to adjust insulation parameters. Please provide your exact site altitude during inquiry.
Q3: What are the thermal and dynamic stability ratings?
Thermal stability is rated at 100 times the rated primary current, while dynamic stability is 2.5 times the thermal stability current. These parameters ensure robust performance during short-circuit events. Verify specific short-circuit durations with our technical team.
Q4: How are these outdoor transformers tested before shipment?
Each unit undergoes routine factory testing, including insulation resistance, ratio, and polarity checks. Special type tests are available subject to specific project requirements. Request the detailed test certificate package with your purchase order.
Q5: Are there specific international certifications for these 35kV epoxy resin transformers?
Our combined transformers comply with standard IEC and GB manufacturing guidelines. Specific international certifications are subject to confirmation based on your target market. Contact our sales department for compliance documentation.
Q6: Where is the JLSZY-35 combined transformer typically applied?
This outdoor epoxy resin combined transformer is primarily used in 35kV AC power networks for energy metering and relay protection. It is suitable for pole-mounted or platform-mounted installations in standard environments.
Q7: Is the insulation level adequate for outdoor 35kV networks?
Yes, the insulation level is rated at 42/95/195 kV for power frequency, lightning impulse, and switching impulse respectively. This ensures reliable dielectric performance. Confirm specific pollution level requirements with our engineers.