Product Overview
The JSZY16-10R Voltage Transformer is a three-phase integrated, epoxy resin cast voltage transformer designed for indoor 10 kV AC power systems with a maximum system voltage of 12 kV.
The product features a compact backpack-type integrated structure and three plug-in high-voltage bushing interfaces. Built-in high-voltage fuses combine voltage transformation, electrical isolation, and primary-side overcurrent protection within a single unit.
It is mainly used for three-phase voltage measurement, energy metering, relay protection, and insulation monitoring in indoor medium-voltage switchgear. Typical applications include 10 kV distribution systems, box-type substations, switching stations, ring main units, and compact switchgear equipped with three-position switches.
Product Features
Insulation and Electrical Performance
- Three-phase integrated cast insulation:
The three-phase windings are enclosed within a single body manufactured using an epoxy resin vacuum-casting process. The solid insulation contains no internal air gaps and provides excellent dielectric performance. - Suitable for 12 kV systems:
The transformer can withstand the operating voltage, power-frequency withstand voltage, and lightning impulse withstand voltage requirements of 10 kV systems with a maximum system voltage of 12 kV. - Oil-free dry-type construction:
The product contains no insulating oil, eliminating the risks of oil leakage, oil contamination, and oil-related fire hazards. It is suitable for indoor oil-free power distribution systems. - Integrated three-phase fuse protection:
An independent high-voltage fuse is built into each phase. The corresponding fuse can operate rapidly in the event of a single-phase earth fault, phase-to-phase overcurrent, or short circuit, helping protect the transformer from damage. - Simplified primary-circuit configuration:
The integrated fuse arrangement reduces the need for external fuse assemblies, simplifies the primary circuit, saves installation space, and lowers the number of components inside the switchgear. - Multiple voltage ratios:
Standard three-phase voltage ratios such as 10/0.1 kV and 10/0.1/0.1 kV are available. - Multiple accuracy classes:
Metering accuracy classes up to Class 0.2 are available, while protection accuracy classes such as 3P and 6P can be customized. - Insulation-monitoring capability:
An optional 100/3 V secondary output can be provided for insulation monitoring and system earth-fault detection. The transformer can also be configured for three-phase five-limb connection arrangements. - Low partial discharge:
The advanced casting process limits partial discharge to no more than 10 pC, helping reduce insulation ageing and improve long-term operating reliability.
Structural and Installation Features
- Fully enclosed three-phase dry-type structure:
The three-phase windings are integrally cast into a single enclosed body with no exposed internal live components. - IP20 protection rating:
The transformer provides an IP20 protection rating and is designed for installation inside indoor switchgear and related electrical equipment. - Compact, space-saving design:
Compared with three separate single-phase voltage transformers, the integrated structure can reduce the required switchgear installation space by approximately 30%. - Backpack-type secondary terminal enclosure:
The secondary terminals are integrated into a compact rear-mounted enclosure, simplifying the overall product layout and facilitating installation in space-limited switchgear. - Three plug-in high-voltage bushing interfaces:
The high-voltage side features three tubular plug-in bushing interfaces suitable for direct connection to compatible three-position switches or cable connectors. - Simplified primary-side installation:
The plug-in connection eliminates additional primary-side wiring, reduces installation procedures, and minimizes potential connection points. - Clearly identified secondary terminals:
The three-phase secondary terminals are grouped and clearly marked. Metering, protection, and insulation-monitoring circuits can be connected separately. - Secure bolt mounting:
The metal base includes fixing holes for horizontal bolt installation inside indoor switchgear. The structure provides reliable mechanical stability and vibration resistance.
Operation and Maintenance Features
- Low-maintenance operation:
The dry-type, oil-free construction eliminates leakage and oil-related fire risks. The epoxy resin body provides high mechanical strength, impact resistance, and ageing resistance. - Convenient fuse replacement:
The built-in fuses can be replaced without special tools after the equipment has been safely de-energised, improving maintenance efficiency. - Wide operating temperature range:
The transformer can operate at ambient temperatures from -30°C to +70°C. The epoxy resin maintains stable insulation and mechanical properties without becoming brittle or deformed. - High-reliability construction:
The magnetic cores are made from high-quality laminated silicon steel sheets, while the windings are wound with enamelled copper wire. - Low operating losses:
The optimized magnetic core and winding design provides low losses, limited temperature rise, and stable measurement accuracy. - Reliable protection performance:
The transformer can withstand switching and lightning overvoltages within its specified insulation level. The built-in fuses provide reliable protection against primary-side overcurrent and short-circuit faults.
Technical Specifications
Electrical Parameters
| Parameter | Specification |
|---|---|
| Applicable System Voltage | 10 kV AC, Um = 12 kV |
| Rated Frequency | 50 Hz |
| Rated Primary Voltage | 10 kV, three-phase |
| Rated Secondary Voltage | 100 V for three-phase metering and protection; optional 100/3 V for insulation monitoring |
| Metering Accuracy Class | Class 0.2 / 0.5 / 1 |
| Protection Accuracy Class | 3P / 6P |
| Power-Frequency Withstand Voltage | 42 kV for 1 minute at the high-voltage terminal, without breakdown |
| Lightning Impulse Withstand Voltage | 75 kV peak, without breakdown |
| Partial Discharge | ≤10 pC |
| Insulation Resistance | ≥1,000 MΩ between high voltage, low voltage, and earth |
| Rated Current of Built-In Fuse | 0.5 A per phase as standard; customizable |
Structural and Material Parameters
| Parameter | Specification |
|---|---|
| Insulating Medium | Fully cast epoxy resin with integrated three-phase construction |
| Protection Rating | IP20 |
| Installation Type | Indoor post-type bolt mounting |
| Thermal Class | Class B, 130°C |
Environmental Parameters
| Parameter | Specification |
|---|---|
| Installation Altitude | ≤2,000 m; high-altitude versions available |
| Operating Temperature | -30°C to +70°C |
| Storage Temperature | -40°C to +85°C |
| Relative Humidity | ≤95%, non-condensing |
Applicable Standards
| Standard | Description |
|---|---|
| GB 1207 | Voltage Transformers |
| GB/T 20840 Series | Instrument Transformers |
| GB 15166.2 | High-Voltage Alternating-Current Fuses |
Applications
Applicable Voltage Level
The JSZY16-10R Voltage Transformer is suitable for indoor 10 kV AC power systems with a maximum system voltage of 12 kV.
Typical Applications
- Three-phase voltage measurement in KYN28 series indoor medium-voltage switchgear
- Ring main units
- Energy metering and relay protection in box-type substations
- Voltage monitoring in distribution and switching stations
- 10 kV distribution systems in industrial and mining enterprises
- Commercial buildings and industrial parks
- Three-phase voltage monitoring, control, and protection signal acquisition in power automation systems
- Compact switchgear fitted with three-position switches
- Direct connection to compatible cable connectors
- Applications requiring integrated primary-side fuse protection
Main Functions
The transformer converts the three-phase system voltage into a standardized secondary voltage, normally 100 V, at a specified ratio.
It supplies three-phase voltage signals to:
- Energy meters
- Measuring instruments
- Relay protection devices
- Monitoring equipment
- Control systems
- Insulation monitoring devices
The transformer also provides electrical isolation between the primary and secondary systems, helping protect connected equipment and operating personnel.
Each phase is equipped with a built-in high-voltage fuse. If primary-side overcurrent or a short circuit occurs, the corresponding fuse operates rapidly to isolate the fault and help protect the transformer.
Where an optional insulation-monitoring winding is provided, the transformer can also supply a residual voltage signal for system earth-fault detection.
Operating Conditions
Normal Operating Conditions
- Installation altitude: no more than 2,000 m
- Ambient temperature: -30°C to +70°C
- Severe or sudden temperature changes should be avoided
- Relative humidity: no more than 95%, non-condensing
- The environment should be free from corrosive gases
- Flammable or explosive substances are not permitted
- Severe vibration and mechanical impact should be avoided
- Significant dust and salt-spray contamination should be avoided
- Indoor post-type installation
- Direct sunlight, rain, and condensation should be avoided
Special Operating Conditions
Customized products are required for:
- Installation altitudes above 2,000 m
- Ambient temperatures outside the range of -30°C to +70°C
- Severe pollution or salt-spray environments
- Chemically corrosive environments
- Applications involving strong vibration or mechanical impact
- Non-standard voltage ratios
- Special accuracy classes
- Non-standard fuse ratings or characteristics
Installation and Maintenance
Installation Requirements
- Pre-installation inspection:
Inspect the voltage transformer and confirm that the epoxy resin body is free from cracks, bubbles, mechanical damage, and other visible defects. Check that all terminal markings are clear and that the supplied accessories are complete. Verify that the model, specifications, voltage ratio, accuracy class, and fuse parameters match the system design requirements. Confirm that the fuse on each phase is complete and undamaged. - Mounting:
Position the transformer at the specified location inside the switchgear and secure it using bolts through the mounting holes in the base. Ensure that the transformer is firmly installed without looseness or displacement. The mounting surface should be level to avoid uneven mechanical stress. - High-voltage plug-in connection:
Insert the compatible three-position switch connectors or cable connectors into the three high-voltage bushing interfaces. Confirm that each connector is fully inserted, correctly positioned, and securely engaged. The contact surfaces must provide reliable electrical contact without looseness or displacement. Maintain adequate electrical clearance between the high-voltage components, earthed parts, and other live components. - Secondary-side connection:
Connect the three-phase secondary terminals according to their markings. Metering, protection, and insulation-monitoring circuits must be wired separately and correctly. The voltage transformer secondary circuits must never be short-circuited. One point of the required secondary circuit must be reliably earthed in accordance with the system design and applicable electrical safety requirements. - Insulation inspection:
After installation, measure the insulation resistance between:- High voltage and low voltage
- High voltage and earth
- Low voltage and earth
Maintenance Requirements
- Regularly inspect the epoxy resin body for cracks, mechanical damage, discharge marks, and contamination.
- Check the high-voltage interfaces for looseness, oxidation, contamination, or abnormal heating.
- Inspect the fuse on each phase and confirm that it has not operated or sustained visible damage.
- Regularly inspect the connection between the plug-in connectors and the three high-voltage bushing interfaces.
- Confirm that all connectors remain fully inserted and securely engaged.
- Check for overheating, discoloration, oxidation, or poor electrical contact at the plug-in interfaces.
- Regularly inspect the secondary wiring to ensure that all connections remain secure and free from overheating or discoloration.
- Confirm that the secondary-circuit earthing remains reliable.
- Periodically test the insulation resistance and three-phase voltage ratio.
- Verify that the metering and protection accuracy remains within the specified limits.
- Check the operating condition of each built-in fuse.
- Clean dust and contamination from the transformer surface.
- Keep the plug-in contact surfaces free from oxidation and contamination.
- Prevent oil and corrosive substances from contacting the epoxy resin body.
- If a fuse has operated or become damaged, de-energise the equipment and replace it with a fuse of the same model and rating.
- Do not use a fuse with an unspecified or incompatible rating.
- If cracking, electrical discharge, overheating, excessive voltage-ratio error, or functional failure is detected, immediately de-energise and inspect the equipment. Replace the transformer where necessary.
Precautions
- The voltage transformer secondary windings must never be short-circuited while the primary system is energised. A secondary short circuit may produce excessive current and create a serious risk to equipment and personnel.
- During maintenance, the transformer must be completely de-energised, and the secondary circuits must be safely isolated and earthed in accordance with applicable procedures.
- Avoid impact or collision with the epoxy resin body and the three high-voltage bushing interfaces during transportation and installation. Mechanical damage may reduce insulation performance and connection reliability.
- Confirm that the high-voltage connectors are fully compatible with the three bushing interfaces before installation.
- Do not force incompatible or misaligned connectors into the high-voltage interfaces, as this may damage the transformer or connector insulation.
- Keep the plug-in contact surfaces clean and free from oxidation or contamination. Poor contact may cause overheating and electrical failure.
- Confirm the correct phase sequence during three-phase wiring. Incorrect phase connections may affect metering and protection functions.
- The equipment must be reliably earthed. The grounding terminal on the metal base must be securely connected to the switchgear grounding busbar.
- Store the product in a dry, ventilated, and shaded environment. Avoid direct sunlight, high temperatures, moisture, compression, and mechanical impact.
- Protect the built-in fuses from moisture and mechanical damage during storage.
- Fuse replacement must only be carried out after the equipment has been completely de-energised. Live replacement is strictly prohibited.
- Installation, commissioning, fuse replacement, and maintenance must be carried out by qualified electrical personnel in accordance with applicable electrical safety procedures.
Standard Supply List
| No. | Item | Function |
|---|---|---|
| 1 | JSZY16-10R Backpack-Type Three-Bushing Voltage Transformer | Main device for three-phase voltage transformation, electrical isolation, and primary-side protection |
| 2 | Mounting Bolts and Washers | Used to secure the voltage transformer during installation |
| 3 | Secondary Terminal Cover | Protects the low-voltage terminals and helps prevent incorrect connections or short circuits |
| 4 | Product Instruction Manual | Provides installation, operation, maintenance, plug-in connection, and fuse-replacement guidance |
| 5 | Product Certificate and Factory Test Report | Provides product quality and performance documentation, including three-phase voltage-ratio and accuracy test data |
| 6 | Spare Fuse, Optional | Used to replace an operated or damaged built-in fuse |
Applicable Standards and Certification
The product complies with the following standards:
- GB 1207, Voltage Transformers
- GB/T 20840.1, Instrument Transformers—Part 1: General Requirements
- GB/T 20840.3, Instrument Transformers—Part 3: Additional Requirements for Inductive Voltage Transformers
- GB 15166.2, High-Voltage Alternating-Current Fuses
The product has passed the applicable type tests, and its performance meets the operating requirements of indoor 10 kV power systems.
