Product Overview
The JSJW-3/6/10G indoor vertical oil-immersed voltage transformer is a three-phase medium-voltage voltage transformer designed for 3kV, 6kV and 10kV AC power systems. It converts the primary system voltage into a standardized 100V secondary voltage signal for metering instruments, voltage monitoring devices, control circuits and relay protection equipment.
Application Position
The JSJW-3/6/10G series is typically installed indoors in medium-voltage distribution rooms, metering panels, switchgear-related measurement circuits, and substation auxiliary measurement systems. Its vertical oil-immersed structure is used where oil-filled insulation and a three-phase voltage signal output are required.
Main Applications
- 3kV, 6kV and 10kV medium-voltage power distribution systems
- Indoor voltage metering and monitoring circuits
- Relay protection voltage input circuits
- Control signal input for medium-voltage electrical systems
- Substation auxiliary measurement and indication systems
- Three-phase voltage measurement where a 100V secondary output is required
Key Specifications
| Item | Specification |
|---|---|
| Model series | JSJW-3 / JSJW-6 / JSJW-10 / JSJW-3/6/10G |
| Product type | Three-phase voltage transformer / potential transformer |
| Installation | Indoor, vertical type |
| Insulation structure | Oil-immersed / oil-filled insulation |
| Rated voltage class | 3kV, 6kV and 10kV |
| Rated voltage ratio | 3000/100V, 6000/100V or 10000/100V according to system voltage |
| Rated frequency | 50Hz or 60Hz |
| Rated secondary voltage | 100V |
| Rated output | According to accuracy class and model specification |
| Pollution class | Class II, unless otherwise specified |
| Main function | Voltage metering, monitoring, control signal input, and relay protection |
Application Fit
Suitable For
- Indoor 3kV, 6kV and 10kV medium-voltage AC systems
- Three-phase voltage metering and monitoring applications
- Power systems requiring a standard 100V secondary voltage signal
- Relay protection circuits that require voltage reference input
- Projects requiring a vertical oil-immersed voltage transformer structure
Not Recommended For
- Outdoor exposed installation without a suitable protective arrangement
- Low-voltage systems below the applicable medium-voltage design range
- Compact indoor switchgear where dry-type or epoxy cast-resin PTs are specified
- Systems requiring special secondary voltage, insulation level, altitude or pollution class without confirmation
Technical Structure
| Component | Description |
|---|---|
| Core | Laminated cold-rolled silicon steel sheet core for electromagnetic voltage transformation |
| Winding | Primary and secondary windings designed for voltage conversion and signal output |
| Insulation | Oil-filled insulation system for dielectric performance and heat dissipation |
| Oil tank | Cylindrical steel oil box with vertical installation structure |
| Primary terminals | Top-mounted porcelain bushings / props for medium-voltage connection |
| Grounding | External grounding bolt provided on the tank body |
| Oil handling | Oil filling and oil draining structure provided according to product design |
Model Designation
The JSJW-3/6/10G model code can be interpreted as follows:
| Code | Meaning |
|---|---|
| J | Voltage transformer |
| S | Three-phase structure |
| J | Oil-filled / oil-immersed insulation type |
| W | Five-prop structure |
| 3 / 6 / 10 | Rated voltage grade: 3kV, 6kV or 10kV |
| G | Product variant / design code according to manufacturer specification |
General Technical Notes
- Rated frequency: 50Hz or 60Hz
- Rated secondary voltage: 100V
- Oil-immersed insulation structure
- Indoor vertical installation
- Used for metering, voltage monitoring, control signal input and relay protection
Installation and Dimensions
The following dimensions are provided as a reference for layout, foundation design, wiring arrangement and installation clearance. Final dimensions should be confirmed with the approved product drawing before installation.
Overall Dimensions
| Model | Overall
Height |
Main
Body Height |
Top
Width |
Tank
Diameter |
Base
Fixing Distance |
Mounting
Holes |
Grounding
Bolt |
|---|---|---|---|---|---|---|---|
| JSJW-6 | 705 mm | 594 mm | 418 mm | Ø368 mm | 248 mm | 4-Ø18 | M12 |
| JSJW-10 | 874 mm | 669 mm | 476 mm | Ø472 mm | 320 mm | 4-Ø18 | M12 |
Note: JSJW-3 dimensions should be confirmed according to the final approved drawing.
Terminal and Wiring Notes
- Primary terminals are arranged on the top of the transformer tank.
- Secondary terminals should be connected according to the approved wiring diagram.
- Grounding shall be completed through the grounding bolt on the tank body.
- Routine wiring diagrams may include Y/Y/△ connection arrangements depending on project requirements.
Compliance and Testing
The JSJW-3/6/10G series is designed for medium-voltage voltage transformer applications. Applicable standards, test requirements and acceptance criteria should be confirmed according to the project specification, local grid requirements and final technical agreement.
Typical Routine Tests
- Visual inspection and nameplate verification
- Ratio verification
- Polarity and terminal marking check
- Accuracy test at specified burden
- Power-frequency withstand voltage test
- Insulation resistance test
- Oil level and sealing inspection
Engineering Notes
- The secondary circuit should not be short-circuited during normal operation.
- Secondary wiring should be connected according to the approved wiring diagram and terminal markings.
- One grounding point should be applied according to project electrical safety rules.
- Check oil level, sealing condition, porcelain bushings and grounding connection during inspection.
- Installation and commissioning should be performed by qualified electrical personnel.
Selection Guide
How to Select the Rated Voltage Ratio
Select the rated voltage ratio according to the primary system voltage. For a 3kV system, select a 3000/100V ratio. For a 6kV system, select a 6000/100V ratio. For a 10kV system, select a 10000/100V ratio. The selected transformer ratio should match the rated voltage input range of the connected meters, relays and monitoring devices.
How to Select the Accuracy Class
Accuracy class should be selected according to the function of the secondary circuit. Higher accuracy classes are used for metering circuits, while standard classes may be used for general voltage indication or monitoring. When the transformer is used for billing, revenue metering or utility measurement, the accuracy class should follow the project metering specification.
How to Confirm Rated Output
The total connected secondary burden should include meters, relays, monitoring devices, wiring loss and any auxiliary equipment connected to the voltage transformer secondary circuit. The total burden should not exceed the rated output corresponding to the required accuracy class.
How to Confirm Installation Size
Before ordering, confirm the overall height, tank diameter, base fixing holes, terminal arrangement, lifting position and grounding point. The final installation space should allow safe clearance for primary terminals, secondary wiring, inspection and maintenance.
Ordering Information
Please provide the following information when ordering or requesting a quotation:
- Product model: JSJW-3, JSJW-6, JSJW-10 or JSJW-3/6/10G
- Rated primary voltage and secondary voltage ratio
- Rated frequency: 50Hz or 60Hz
- Required accuracy class
- Rated output / burden requirement
- Insulation level or system voltage class
- Wiring diagram or connection group requirement
- Installation site condition: indoor, altitude, pollution level, ambient temperature
- Quantity
- Special requirements for drawings, test reports, certificates, nameplate language, packaging or shipping