Overview
The JSJW-6 / JSJW-10 is a three-phase, five-limb oil-immersed voltage transformer (potential transformer) designed for 6kV, 10kV, 11kV and 12kV class AC power systems operating at 50Hz or 60Hz. It features a sealed oil tank, porcelain bushings, laminated silicon-steel core, and No. 25 transformer oil as the insulating medium, ensuring high dielectric strength, effective heat dissipation, and long-term insulation stability.
This PT supports accuracy classes of 0.2, 0.5, 1, 3 and 6P, making it suitable for energy metering, voltage monitoring, relay protection, and residual-voltage detection in utility and industrial applications. It complies with international standards including IEC 61869-3, IEC 61869-1, IEC 60044-2, and GB1207-2006, and is preferred in projects where oil-immersed insulation is specified over cast-resin alternatives.
Key Ratings Snapshot
| Parameter | Rating |
|---|---|
| Product type | Three-phase, five-limb oil-immersed PT |
| Rated voltage class | 6kV, 10kV, 11kV, 12kV (by confirmation) |
| Rated voltage ratio | 6000/100V, 10000/100V, 10/√3 : 0.1/√3 : 0.1/3 or project-specified |
| Rated frequency | 50Hz / 60Hz |
| Accuracy classes | 0.2, 0.5, 1, 3, 6P |
| Residual-voltage winding | da/dn open-delta output |
| Insulation medium | No. 25 transformer oil |
| Insulation level (6kV class) | 7.2/32/60kV |
| Insulation level (10–12kV class) | 12/42/75kV |
| Antipollution class | Class II |
| Installation form | Stand type or lying type |
| Applicable standards | IEC 61869-3, IEC 61869-1, IEC 60044-2, GB1207-2006 |
Model Designation
- J: Voltage transformer / potential transformer
- S: Three-phase structure
- J: Oil-immersed insulation structure
- W: Five-limb / five-post core structure
- 6 / 10: Catalogue voltage grade reference in kV
- JSJW-11 / JSJW-12: International voltage-class designation for 11kV and 12kV class projects, subject to insulation and ratio confirmation
Construction
The JSJW series PT consists of a sealed oil tank, porcelain bushings, laminated silicon-steel core, primary and secondary windings, residual-voltage winding, grounding bolt, oil drain and filling components, and a mounting base. Porcelain bushings are mounted on the tank cover and connected to the primary terminals. Lifting lugs are provided for safe handling and installation.
The oil-immersed insulation system, using standard No. 25 transformer oil, ensures reliable dielectric strength, efficient heat dissipation, and long-term insulation stability. The sealed tank design minimizes exposure of internal components to moisture and contaminants, thereby reducing insulation ageing and enhancing operational reliability in both indoor and outdoor environments.
Technical Parameters
Service Conditions
- Ambient temperature: -5°C to +40°C
- Altitude: Not exceeding 1000 m above sea level
- Relative humidity: Average value not more than 95% at 25°C
- Installation environment: Indoor, non-corrosive, non-explosive, free from severe vibration and shock
Technical Parameters
The JSJW-6 and JSJW-10 are three-phase oil-immersed voltage transformers designed for indoor use in AC 50 Hz systems. They feature cast-resin insulation construction, operate within a temperature range of -5°C to +40°C, and are suitable for installations up to 1000 m altitude. These units comply with international PT terminology standards and support rated outputs from 60 VA to 960 VA depending on model and accuracy class.
Voltage Transformer Data
| Model | Rated Voltage Ratio |
Accuracy Class Rated Output (VA) |
Limit Output (VA) |
Rated Insulation Level (kV) |
|---|---|---|---|---|
| JSJW-6 | 6000 / 100V or 6/√3 : 0.1/√3 : 0.1/3 |
0.2: by agreement 0.5: 80VA 1: 150VA 3: 320VA 6P: by agreement |
640VA | 7.2 / 32 / 60kV |
| JSJW-10 | 10000 / 100V or 10/√3 : 0.1/√3 : 0.1/3 |
0.2: 60VA 0.5: 120VA 1: 200VA 3: 480VA 6P: by agreement |
960VA | 12 / 42 / 75kV |
| JSJW-11 | 11000 / 110V or 11/√3 : 0.11/√3 : 0.11/3 by agreement |
0.2 / 0.5 / 1 / 3 / 6P by technical agreement |
By agreement | 12 / 42 / 75kV by confirmation |
| JSJW-12 | 12000 / 110V or 12/√3 : 0.11/√3 : 0.11/3 by agreement |
0.2 / 0.5 / 1 / 3 / 6P by technical agreement |
By agreement | 12 / 42 / 75kV by confirmation |
Installation & Wiring
Installation Diagram
The JSJW-6 and JSJW-10 voltage transformers are installed either in a vertical stand type configuration or horizontal lying type arrangement depending on site constraints. Stand type units are mounted via four Φ18 holes at the base with specified mounting references (248mm for JSJW-6, 320mm for JSJW-10). Lying type installation is used where vertical clearance is limited.
Wiring Diagram
The wiring diagram shows standard terminal markings for primary and secondary windings. Primary terminals are labeled A, B, C and N. Secondary metering windings are marked as a, b, c and n, while protection windings (if present) follow the same phase sequence. Residual (open-delta) output terminals are designated da and dn for earth-fault detection applications. Ensure correct polarity and phase alignment during connection.
Selection & FAQs
Selection Guide
- Select JSJW oil-immersed PTs for applications requiring voltage measurement, energy metering, voltage monitoring, residual-voltage detection, and relay protection in medium-voltage systems.
- Choose JSJW over cast-resin types (e.g., JSZW or JDZ) when oil insulation, sealed tank construction, and utility-style design are preferred.
- Confirm voltage class—catalogue models include JSJW-6 and JSJW-10, but 11kV and 12kV ratings can be supported with verified voltage ratio, insulation level, and project standards.
- Specify if a residual-voltage winding is needed for earth-fault detection via open-delta connection at da/dn terminals.
- Verify transformer oil type—standard is No. 25 transformer oil; special requirements must be agreed upon before ordering.
Frequently Asked Questions
Q1: Can the JSJW-10 voltage transformer be installed outdoors?
No, it is strictly designed for indoor installation. The environment must be non-corrosive, non-explosive, and free from severe vibration. Contact us for outdoor-rated alternatives.
Q2: Which accuracy class provides the highest output for JSJW-10?
The 3.0 accuracy class provides the highest standard rated output at 480 VA. For the 0.2 class, the output is 60 VA. Confirm exact requirements with our engineering team.
Q3: What is the rated voltage ratio for the JSJW-6 model?
The JSJW-6 offers a standard ratio of 6000/100V or 6/√3 : 0.1/√3 : 0.1/3. Its rated insulation level is 7.2/32/60 kV. Specify your exact primary voltage during inquiry.
Q4: Are specific factory tests performed before shipping?
Standard routine tests are conducted to ensure compliance with international PT terminology standards. Special type tests are subject to confirmation. Request the test report format from our team.
Q5: How long is the standard delivery time for bulk orders?
Lead times depend on order quantity and current production schedules. Delivery details and specific certification requirements are subject to confirmation. Contact our sales team for an accurate quote.
Q6: Where are these three-phase voltage transformers typically applied?
They are designed for AC 50 Hz indoor power systems up to 1000 m altitude. These units measure voltage and provide signals for metering and protection.
Q7: Which model supports a higher limit output capacity?
The JSJW-10 model supports a higher limit output of 960 VA compared to the 640 VA limit of the JSJW-6. Verify your total connected burden before finalizing the selection.