Overview
The JSZY-6/10/450-550 is an indoor three-phase epoxy cast-resin voltage transformer designed for 6kV and 10kV medium-voltage systems, corresponding to international voltage classes of 7.2kV and 12kV. It features a fully encapsulated epoxy cast-resin insulation structure, ensuring high dielectric strength and mechanical robustness for indoor switchgear applications.
This transformer delivers accurate secondary voltage signals for energy metering, relay protection, and system monitoring in 50Hz or 60Hz power networks. It complies with GB20840.1-2010 and GB20840.3-2013 standards and supports Y/△ and Y/Y/△ secondary wiring schemes, making it suitable for handcart-type switchgear where integrated three-phase voltage sensing is required.
Key Ratings Snapshot
| Parameter | Rating |
|---|---|
| System Voltage | 6kV / 10kV |
| Voltage Class | 7.2kV / 12kV |
| Frequency | 50Hz / 60Hz |
| Insulation Type | Epoxy cast-resin |
| Installation Type | Handcart switchgear |
| Phase Configuration | Three-phase |
| Wiring Schemes | Y/△, Y/Y/△ |
| Rated Insulation Level (6kV) | 7.2/30/60kV |
| Rated Insulation Level (10kV) | 12/42/75kV |
| Ambient Temperature Range | -25°C to +40°C |
| Typical Functions | Metering, protection, residual-voltage monitoring |
| Standards | GB20840.1-2010, GB20840.3-2013 |
Model Designation
- J: Voltage transformer
- S: Three-phase structure
- Z: Epoxy cast-resin insulation
- Y: Handcart / switchgear structure code, per manufacturer designation
- 6 / 10: Rated system voltage code for 6kV or 10kV applications
- 450-550: Handcart switchgear installation size code
Construction
The JSZY-6/10/450-550 features a monolithic three-phase epoxy cast-resin construction, where all primary and secondary windings are fully encapsulated in high-grade epoxy resin under vacuum conditions. This provides excellent resistance to partial discharge, moisture ingress, and mechanical stress. The core is made of grain-oriented electrical steel, optimized for low excitation current and minimal ratio error. Secondary terminals are arranged on a standardized terminal block at the bottom or rear of the unit, ensuring compatibility with common handcart switchgear wiring schemes. The entire assembly is designed for withdrawable installation in 550-series switchgear compartments, with reinforced mounting points and clear phase identification markings.
Technical Parameters
Service Conditions
- Ambient temperature: -5°C to +40°C
- Altitude: up to 1000 m above sea level
- Relative humidity: daily average not exceeding 95%, monthly average not exceeding 90%
- Installation environment: indoor, non-corrosive, free from explosive or flammable gases and conductive dust
Technical Parameters
The JSZY-6 and JSZY-10/450-550 are three-phase epoxy cast-resin voltage transformers designed for 7.2kV and 12kV systems respectively. They feature high insulation strength, operate within a standard ambient temperature range of -5°C to +40°C, and are suitable for installation up to 1000 m altitude. The units comply with relevant international standards for medium-voltage instrument transformers and support multiple secondary output configurations.
Voltage Transformer Data
| Model | Rated Voltage Ratio |
Insulation Level (kV) |
Accuracy Class / Rated Output |
Max. Output (VA) |
|---|---|---|---|---|
| JSZY-6/450-550 | 6/√3 : 0.1/√3 : 0.1/3 | 7.2/30/60kV | 0.2/3P—10/50 0.2/6P—10/50 0.5/3P—30/50 0.5/6P—30/50 |
350VA |
| 6/√3 : 0.1/√3 : 0.22/√3 : 0.1/3 | 0.5/3.0/3P—3×30/3×150/50 0.5/3.0/6P—3×30/3×150/50 |
350VA | ||
| JSZY-10/450-550 | 10/√3 : 0.1/√3 : 0.1/3 | 12/42/75kV | 0.2/3P—3×10/50 0.2/6P—3×10/50 0.5/3P—3×30/50 0.5/6P—3×30/50 |
350VA |
| 10/√3 : 0.1/√3 : 0.22/√3 : 0.1/3 | 0.5/3.0/3P—3×30/3×150/50 0.5/3.0/6P—3×30/3×150/50 |
350VA |
Installation & Wiring
Installation Diagram
The JSZY-6 and JSZY-10/450-550 three-phase epoxy cast-resin voltage transformers are designed for secure mounting on a flat surface using the base dimensions provided. Ensure adequate clearance around the unit for ventilation and maintenance access. The grounding bolt (M8 reference) must be connected to a reliable earth ground before energizing.
Wiring Diagram
The wiring diagram illustrates two common configurations: Y/△ for three-winding setups and Y/Y/△ for four-winding setups. Secondary terminals may include 1a, 1b, 1c, 2a, 2b, 2c, da, and dn depending on the selected configuration. Always verify the residual-voltage output terminal wiring prior to connecting protection relays. Confirm terminal polarity, grounding integrity, and handcart position before applying power.
Selection & FAQs
Selection Guide
- Match the voltage class: choose JSZY-6 for a 6kV system with 7.2/30/60kV insulation, or JSZY-10 for a 10kV system with 12/42/75kV insulation.
- Select the winding scheme: use Y/△ for 100/√3V measurement plus residual voltage, or Y/Y/△ when a separate 220/√3V auxiliary circuit is also required.
- Coordinate accuracy and burden: choose class 0.2 or 0.5 for measurement and 3P or 6P at 50VA for protection; confirm whether every quoted VA value is per phase or total.
- Verify handcart compatibility: treat 450-550 as an installation-size code and approve the complete mechanical drawing, contacts, interlocks, service position and test position against the switchgear.
- Confirm service conditions: validate terminal allocation, M8 earth connection, −5°C standard minimum, 1000m altitude limit, secondary fusing and any required low-temperature version.
Frequently Asked Questions
Q1: Which model is suitable for 12kV medium-voltage switchgear?
The JSZY-10/450-550 model is designed specifically for 12kV systems. It features high insulation strength and epoxy cast-resin construction. Contact us to confirm exact insulation levels for your project.
Q2: What are the indoor installation environmental requirements?
Installation must be indoors, free from explosive gases, flammable gases, and conductive dust. The ambient temperature should remain between -5°C and +40°C. Contact our engineers to verify site conditions before ordering.
Q3: Can the 0.2 accuracy class support 350VA output?
Yes, the 0.2 accuracy class supports a maximum output of 350VA for the JSZY-6 model. Select 0.2 for precise metering and 0.5 for general measurement. Specify your exact ratio requirements during ordering.
Q4: Are custom secondary voltage output ratios available?
Multiple secondary output configurations are supported, including 0.1/√3 and 0.22/√3. Custom ratio configurations are subject to factory confirmation. Please provide your specific rated voltage ratio requirements for engineering evaluation.
Q5: Do you provide factory test reports before shipment?
Standard routine tests for medium-voltage instrument transformers are conducted prior to dispatch. Specific type tests or special certification requirements are subject to confirmation. Contact our sales team for detailed test reports.
Q6: Why are these epoxy cast-resin transformers restricted to indoor use?
The JSZY series is strictly designed for indoor installation environments to prevent moisture and dust ingress. They are not rated for outdoor exposure or corrosive conditions. Please inquire about outdoor-rated models if needed.
Q7: How does high altitude affect the transformer’s performance?
Standard models are rated for altitudes up to 1000 m above sea level. For installations exceeding this altitude, derating or special design modifications are required. Contact our engineers for altitude-specific technical solutions.