Overview
The JLSZY-35W is a three-phase three-component combined transformer rated for 35kV medium-voltage distribution systems. It features an integrated design combining current transformers (CT) and voltage transformers (PT/VT) in a single outdoor-rated epoxy cast-resin assembly, providing accurate current and voltage signals for high-voltage energy metering.
Designed for utility and industrial revenue metering, it supports active and reactive energy measurement with enhanced insulation performance suitable for 40.5kV class applications. Commonly deployed at outdoor 35kV metering points—including pole-mounted installations, compact substations, and user-side high-voltage metering systems—it complies with relevant IEC and GB standards for accuracy and insulation coordination in outdoor environments.
Key Ratings Snapshot
| Parameter | Rating |
|---|---|
| System Voltage | 35kV |
| Insulation Level | 40.5kV |
| Primary Current Range | Up to 1200A |
| Secondary Current | 5A or 1A |
| Secondary Voltage | 100/√3 V or 100 V |
| Accuracy Class (CT) | 0.2S / 0.5S |
| Accuracy Class (PT) | 0.2 / 0.5 |
| Frequency | 50 Hz |
| Phase Configuration | Three-phase, three-component |
| Installation Type | Outdoor |
| Anti-Resonance Protection | Integrated |
| Insulation Material | Epoxy cast-resin |
Construction
The JLSZY-35W is constructed as a monolithic epoxy cast-resin assembly, integrating three current transformers and three voltage transformers into a single outdoor housing. The core and windings are fully encapsulated in high-grade epoxy resin, providing excellent mechanical strength, moisture resistance, and long-term dielectric stability. The primary terminals are designed for direct connection to 35kV overhead lines or cable terminations, while the secondary wiring is routed to a sealed terminal box with IP54 protection. An integrated anti-resonance device is embedded within the voltage transformer section to suppress ferroresonance under switching or fault conditions. All external surfaces feature UV-resistant coating suitable for prolonged outdoor exposure.
Technical Parameters
Service Conditions
- Installation position: Outdoor pole-mounted, outdoor metering box, compact substation or user-side metering point
- Ambient temperature: -25°C to +55°C
- Maximum altitude: ≤ 4500m (no derating required)
- System voltage: 35kV (40.5kV maximum insulation level)
- Grounding: Connect grounding terminal per local electrical codes and metering standards
- Anti-resonance device: Ensure proper connection of integrated anti-resonance device in neutral circuit
Technical Parameters
The JLSZY-35W is a three-phase, three-component outdoor epoxy cast-resin combined transformer designed for 35kV systems. It operates within an ambient temperature range of -25°C to +55°C and at altitudes up to 4500m without derating. The unit complies with GB20840.4-2015 and IEC 61869.4:2013 standards and supports primary current ratings from 5A up to 1200A.
Voltage Transformer Data
| Type (Ratio) |
Rated Insulation Level (kV) |
Accuracy Class / Rated Output |
Max. Output (VA) |
|---|---|---|---|
| 35/√3 / 0.1/√3 / 0.1/3 kV | 40.5/95/200 | 0.2 / 3P — 3×40 VA | 600 VA |
Current Transformer Data
| Rated Primary Current (A) |
Rated Insulation Level (kV) |
Accuracy Class / Rated Output |
Short-Time Thermal Current |
Dynamic Current |
|---|---|---|---|---|
| 5 – 600 | 40.5/95/185 | 0.2S — 3×15 VA | 80 × In | 200 × In |
| 750 – 800 | 40.5/95/185 | 0.2S — 3×15 VA | 80 kA | 200 kA |
| 1000 – 1200 | 40.5/95/185 | 0.2S — 3×15 VA | 80 kA | 200 kA |
Installation & Wiring
Installation Diagram
The JLSZY-35W transformer is designed for pole-mounted or platform installation in 35kV three-phase systems. Ensure adequate clearance around the unit for maintenance and safety, and secure it firmly using the provided mounting points. Follow local utility regulations for height, orientation, and grounding during installation.
Wiring Diagram
The wiring diagram shows terminal markings for both current transformers (CTs) and voltage transformers (PTs). Confirm the correct phase sequence at terminals AP1/AP2, BP1/BP2, and CP1/CP2 before energizing. CT secondary windings must never be left open-circuited during operation. PT secondaries supply voltage signals to metering and monitoring equipment, while CT secondaries provide current inputs to active and reactive energy meters. All grounding and meter box connections must adhere strictly to the approved project wiring diagram. Additionally, verify that the anti-resonance device is correctly installed in the neutral circuit to prevent ferroresonance.
Selection & FAQs
Selection Guide
- Select for 35kV systems (40.5kV class) based on system voltage requirements.
- Choose CT primary current from 5A to 1200A, segmented into 5–600A, 750–800A, and 1000–1200A ranges according to load conditions.
- Specify CT secondary current as either 5A or 1A depending on metering equipment compatibility.
- Use 0.2S CT accuracy class for high-precision revenue metering applications.
- Select PT ratio as 35/√3 / 0.1/√3 / 0.1/3 kV to match network voltage and meter input specifications.
Frequently Asked Questions
Q1: Can this 35kV combined transformer be installed outdoors?
Yes, it is designed for outdoor pole-mounted or compact substation installation. It operates in ambient temperatures from -25°C to +55°C. Ensure proper grounding per local electrical codes.
Q2: Which accuracy class does the voltage transformer provide?
The unit features a 0.2 accuracy class for metering and 3P for protection. It delivers a rated output of 3×40 VA with a maximum output of 600 VA. Contact us for specific calibration certificates.
Q3: Is derating required for the 35kV transformer at high altitudes?
No derating is required for altitudes up to 4500m. The epoxy cast-resin design maintains full insulation levels of 40.5/95/200 kV in these conditions. Specify your exact site altitude during ordering.
Q4: What international standards does this combined transformer comply with?
The JLSZY-35W complies with GB20840.4-2015 and IEC 61869.4:2013 standards. It is a three-phase, three-component outdoor unit rated for 35kV systems. Request the type test report from our sales team.
Q5: Can the primary current rating be customized for our project?
Yes, primary current ratings can be selected from 5A up to 1200A. Custom ratios are subject to factory confirmation based on your single-line diagram. Please provide your exact technical requirements for a quote.
Q6: What is the primary application of the JLSZY-35W transformer?
This combined transformer is used for 35kV outdoor metering and protection. It integrates CT and VT functions into a single epoxy cast-resin unit. Contact us to verify suitability for your specific substation layout.
Q7: How do we handle ferroresonance in this 35kV system?
The JLSZY-35W includes an integrated anti-resonance device. You must ensure the proper connection of this device in the neutral circuit during installation. Consult the wiring diagram for specific grounding terminal details.