Overview
The JSJW-3G/JSJW-6G/JSJW-10G is a three-phase, indoor vertical oil-immersed voltage transformer designed for medium-voltage AC systems rated at 3kV, 6kV, or 10kV. It features an oil-filled insulation system that provides reliable dielectric strength and thermal stability under continuous operation.
This transformer delivers a standardized secondary output of 100V, suitable for integration with metering instruments, relay protection relays, control circuits, and voltage monitoring equipment. It complies with standard accuracy classes for measurement and protection applications in indoor substations, switchgear panels, and auxiliary power systems operating at 50Hz or 60Hz.
Key Ratings Snapshot
| Parameter | Rating |
|---|---|
| System Voltage | 3kV / 6kV / 10kV |
| Secondary Voltage | 100V |
| Frequency | 50Hz or 60Hz |
| Phase Configuration | Three-phase |
| Insulation Type | Oil-immersed |
| Installation Position | Indoor, vertical |
| Application | Metering, monitoring, relay protection, control |
| Construction Type | Five-limb core |
Model Designation
- J: Voltage transformer
- S: Three-phase structure
- J: Oil-filled / oil-immersed insulation type
- W: Five-limb (five-prop) core structure
- 3 / 6 / 10: Rated voltage grade (3kV, 6kV, or 10kV)
- G: Manufacturer-specific design variant
Construction
The JSJW-3G/JSJW-6G/JSJW-10Gfeatures a robust vertical oil-immersed construction, with windings encapsulated in high-quality insulating oil within a sealed tank. The core employs a five-limb (five-prop) magnetic circuit design, which enhances magnetic balance and reduces zero-sequence voltage errors in three-phase systems. All internal components are housed in a grounded metal enclosure suitable for indoor environments, ensuring long-term reliability and stable performance under normal operating conditions. The unit is not intended for outdoor use or compact switchgear applications where dry-type or cast-resin transformers are preferred.
Technical Parameters
Service Conditions
- Ambient temperature: -5°C to +40°C
- Altitude: Not exceeding 1000 meters above sea level
- Relative humidity: Average daily value not more than 95%, average monthly value not more than 90%
- Installation environment: Indoor, vertical installation only; free from explosive or corrosive gases and dust
- Seismic intensity: Not exceeding 8 degrees (0.2g)
Technical Parameters
The JSJW-3/6/10G is an indoor, vertical, oil-immersed three-phase voltage transformer designed for 3kV, 6kV, and 10kV systems. It features oil-filled insulation, operates within a standard ambient temperature range of -5°C to +40°C, and is suitable for installations up to 1000 meters altitude. The unit complies with relevant IEC and GB standards for voltage transformers used in metering, monitoring, protection, and control applications.
| Type | Voltage Ratio(V) |
Rated output(vA) |
Limit output(vA) |
Rated insulated level(kV) |
|||
|---|---|---|---|---|---|---|---|
| 0.2 | 0.5 | 1 | 3 | ||||
| JSJW-6 | 6000/100 | 80 | 150 | 320 | 640 | 7.2/32/60 | |
| JSJW10 | 10000/100 | 60 | 120 | 200 | 480 | 960 | 12/42/75 |
Installation & Wiring
Installation Diagram
The transformer is designed for indoor vertical installation on a flat, level surface. Mounting is achieved using four anchor bolts through the base fixing holes (4-Ø18). Ensure adequate clearance around the unit for ventilation, maintenance access, and electrical safety as per local codes. Final positioning must align with the approved foundation layout.
Wiring Diagram
Primary terminals are located on the top of the tank and must be connected according to system voltage requirements. Secondary terminals are accessible via the terminal box and should be wired strictly in accordance with the approved wiring diagram. Standard configurations may include Y/Y/△ connections based on project specifications. All secondary circuits must be grounded at a single point. Grounding of the transformer tank is accomplished through the dedicated M12 grounding bolt on the tank body.
Selection & FAQs
Selection Guide
- Select the rated voltage ratio based on system voltage: 3000/100V for 3kV, 6000/100V for 6kV, or 10000/100V for 10kV systems.
- Choose the accuracy class according to the secondary circuit function—higher classes for metering, standard classes for monitoring or indication.
- Ensure the total secondary burden (including meters, relays, wiring loss, and auxiliary devices) does not exceed the transformer’s rated output at the specified accuracy class.
- Verify installation dimensions such as height, tank diameter, base hole pattern, terminal layout, lifting points, and grounding location before ordering.
- Confirm indoor installation suitability, including ambient temperature, altitude, pollution level, and required clearances for operation and maintenance.
Frequently Asked Questions
Q1: What applications suit this three-phase voltage transformer?
It is designed for metering, monitoring, protection, and control in 3kV, 6kV, and 10kV indoor systems. The unit complies with relevant IEC and GB standards. Contact our engineering team for specific application drawings.
Q2: Can this oil-immersed transformer be installed outdoors?
No, it is strictly designed for indoor vertical installation only. The environment must be free from explosive gases, corrosive elements, and excessive dust. Verify your site conditions before ordering.
Q3: Which accuracy class is available for measurement?
The JSJW-3/6/10G offers 0.2, 0.5, 1, and 3 accuracy classes for rated outputs up to 320VA. Select 0.2 or 0.5 for precise metering applications. Confirm your required burden with our technical staff.
Q4: What international standards does this voltage transformer meet?
The unit complies with relevant IEC and GB standards for voltage transformers. Factory test reports and compliance certificates are provided upon request. Specify your exact certification requirements during inquiry.
Q5: How to order a custom voltage ratio?
Standard ratios include 6000/100V and 10000/100V. Custom primary voltage ratios are available subject to factory confirmation. Provide your exact system voltage and burden requirements to our sales team.
Q6: Is this a three-phase or single-phase unit?
The JSJW series is an oil-immersed three-phase voltage transformer. It integrates three single-phase units into a single tank for compact indoor switchgear installation. Request the general arrangement drawing from our manufacturer portal.
Q7: What is the maximum operating altitude for this transformer?
The standard design is rated for altitudes not exceeding 1000 meters above sea level. For higher elevations, derating or custom design is required. Contact us for altitude-specific technical adjustments.