JSZY-6, JSZY-10/450-550 Three-Phase Epoxy Cast-Resin Voltage Transformer

Product Overview

JSZY-6/10/450-550 is an indoor three-phase epoxy cast-resin voltage transformer designed for 550 handcart switchgear and medium-voltage distribution systems. It is suitable for 50Hz / 60Hz power systems and provides secondary voltage signals for energy metering, voltage monitoring and relay protection.

This model should be positioned differently from compact single-phase JDZ-type VTs and anti-ferroresonance JSZJK-type VTs. JSZY-6/10/450-550 is best described as a handcart switchgear voltage transformer with an integrated three-phase cast-resin structure, suitable for withdrawable switchgear where mechanical fit, secondary terminal arrangement and wiring scheme compatibility are important.

Product Display

Application Position

The JSZY-6/10/450-550 transformer is normally installed in indoor handcart switchgear or removable voltage transformer compartments. It provides voltage signals for metering instruments, protection relays and power monitoring devices. The product supports Y/△ connection and Y/Y/△ connection schemes according to the secondary winding configuration.

Main Applications

• Indoor 6kV and 10kV medium-voltage switchgear
• 7.2kV and 12kV class withdrawable handcart switchgear
• Voltage measurement and energy metering circuits
• Relay protection voltage input circuits
• Residual-voltage or open-delta monitoring circuits
• Three-phase integrated VT applications where handcart installation is required

Key Specifications

Application Fit

Suitable For

• 550 handcart switchgear or withdrawable voltage transformer compartments
• Indoor 6kV and 10kV medium-voltage systems
• Projects requiring a three-phase integrated VT instead of separate single-phase units
• Metering and protection schemes requiring Y/△ or Y/Y/△ wiring
• Switchgear designs requiring fixed mechanical dimensions and clear secondary terminal access

Not Recommended For

• Outdoor exposed installations without suitable enclosure protection
• Compact fixed cabinets where a handcart-type VT structure cannot be installed
• Applications requiring oil-immersed insulation
• High-frequency electronic transformer applications
• Systems above the listed 7.2kV / 12kV insulation classes without technical confirmation

Installation Conditions

• Installation location: indoor handcart switchgear or protected indoor cabinet
• Rated frequency: 50Hz / 60Hz power-frequency AC system
• Ambient temperature: -25°C to +40°C
• Mechanical fit: confirm handcart width, base length, secondary terminal position and insertion clearance
• Electrical clearance: confirm primary terminal clearance according to the switchgear design
• Maintenance: inspect resin surface, secondary terminals and grounding point during routine maintenance

Technical Structure

The JSZY-6/10/450-550 series uses an integrated three-phase epoxy cast-resin structure. Its body, terminal arrangement and mounting base are designed around handcart switchgear installation, making it different from ordinary fixed indoor voltage transformers.

Model Designation

• J = Voltage transformer
• S = Three-phase structure
• Z = Epoxy cast-resin insulation
• Y = Handcart / switchgear structure code, subject to manufacturer designation
• 6 / 10 = Rated system voltage code for 6kV or 10kV applications
• 450-550 = Handcart switchgear structure or installation size code

Technical Data

The following data is organized from the JSZY-6/10/450-550 sample. For international product pages, the 6kV and 10kV versions should be expressed as 7.2kV class and 12kV class respectively.

Technical notes:

• One transformer is supplied with one selected accuracy class and rated output combination.
• The 0.1/√3 output is typically used for metering or voltage monitoring.
• The 0.22/√3 output can be selected when the project requires additional secondary voltage output.
• The 0.1/3 output can be used for residual-voltage or open-delta protection functions.
• If required data exceeds the listed scope, parameters should be confirmed by agreement between manufacturer and purchaser.

Installation and Dimensions

Dimension Reference

Terminal and Wiring

• The drawing shows Y/△ connection for three-winding configuration.
• The drawing also shows Y/Y/△ connection for four-winding configuration.
• Secondary terminals may include 1a, 1b, 1c, 2a, 2b, 2c, da and dn depending on the selected configuration.
• Confirm residual-voltage output terminal wiring before connecting protection relays.
• Terminal polarity, grounding and handcart position should be checked before energizing.

Compliance and Testing

The product information references GB20840.1-2010 and GB20840.3-2013. For export projects, final standard references should be confirmed according to the buyer’s specification and project technical agreement.

Typical Routine Tests

• Visual inspection and nameplate verification
• Ratio verification
• Polarity and terminal marking check
• Accuracy test at specified rated burden
• Power-frequency withstand voltage test
• Induced withstand voltage test where applicable
• Insulation resistance test
• Secondary terminal and wiring verification
• Grounding point inspection

Engineering Notes

• Use JSZY-6/450-550 for 6kV systems and JSZY-10/450-550 for 10kV systems.
• For international pages, express the voltage classes as 7.2kV and 12kV according to insulation level.
• This model is specifically suited for handcart switchgear, so mechanical fit is as important as electrical specification.
• Confirm whether the switchgear requires Y/△ or Y/Y/△ wiring before production.
• Check the 65kg weight and front terminal position before approving the handcart compartment design.
• Do not describe this product as a high-frequency transformer; it is a 50Hz / 60Hz power-frequency VT/PT.

Selection Guide

Select by switchgear structure: Choose JSZY-6/10/450-550 when the project uses 550 handcart switchgear or withdrawable VT compartments. For fixed cabinet installation, confirm whether another fixed-type VT is more suitable.

Select by voltage class: Use JSZY-6/450-550 for 6kV systems and JSZY-10/450-550 for 10kV systems. On export pages, express them as 7.2kV and 12kV class products.

Select by wiring scheme: Use Y/△ wiring when the project needs a standard three-winding configuration. Use Y/Y/△ wiring when additional secondary output or more complete monitoring/protection configuration is required.

Select by secondary function: Confirm whether the system needs metering output, protection output, 0.22/√3 output or 0.1/3 residual-voltage output before confirming the technical table.

Select by inquiry clarity: A clear inquiry should include model, system voltage, voltage ratio, wiring scheme, accuracy/output combination, insulation level, handcart size and quantity.

FAQs