Overview
The JSJW-6 and JSJW-10 are three-phase, five-limb oil-immersed voltage transformers (also known as potential transformers or PTs), designed for 6kV, 10kV, 11kV, and 12kV class AC power systems operating at 50Hz or 60Hz. These units utilize a sealed oil tank filled with No. 25 transformer oil, porcelain bushings, and a laminated silicon-steel core to provide reliable dielectric strength, thermal stability, and long-term insulation performance.
Available in accuracy classes 0.2, 0.5, 1, 3, and 6P, the JSJW series supports energy metering, voltage monitoring, relay protection, and residual-voltage detection via an open-delta da/dn winding. It complies with international standards including IEC 61869-3, IEC 60044-2, and GB1207-2006, making it suitable for utility and industrial applications where oil-immersed PTs are specified over cast-resin alternatives.
Key Ratings Snapshot
| Parameter | Rating |
|---|---|
| Rated voltage class | 6kV, 10kV, 11kV, 12kV |
| 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 |
| Insulation medium | No. 25 transformer oil |
| Insulation level (6kV class) | 7.2/32/60kV |
| Insulation level (10–12kV class) | 12/42/75kV |
| Residual-voltage winding | da/dn open-delta output |
| Core structure | Five-limb laminated silicon steel |
| Antipollution class | Class II |
| Installation type | Stand or lying type |
| Applicable standards | IEC 61869-3, 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 designations for 11kV and 12kV class projects, subject to insulation and ratio confirmation
Construction
The JSJW series features a sealed oil tank housing a laminated silicon-steel core, primary and secondary windings, and a dedicated residual-voltage winding for earth-fault detection. Porcelain bushings mounted on the tank cover provide primary terminal connections, while a grounding bolt ensures safety. The unit includes oil drain and filling components, lifting lugs for handling, and a robust mounting base. Filled with No. 25 transformer oil, the oil-immersed insulation system delivers high dielectric strength, effective heat dissipation, and long-term insulation stability. The hermetically sealed tank minimizes moisture and contaminant ingress, enhancing operational reliability in both indoor and outdoor environments under standard service conditions.
Technical Parameters
Service Conditions
- Ambient temperature: -5°C to +40°C
- Altitude: Not exceeding 1000 m above sea level
- Relative humidity: Average daily value not more than 95%, average monthly value not more than 90%
- Installation environment: Indoor installation, free from severe vibration, shock, and explosive or corrosive gases
Technical Parameters
The JSJW-6 and JSJW-10 are three-phase oil-immersed voltage transformers designed for 6kV and 10kV systems respectively. They feature cast-resin insulation, 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 standards and support multiple accuracy classes with rated outputs ranging from 60VA to 480VA depending on model and configuration.
| Type | Rated voltage Tation(V) | Rated output(vA) | Limit output(vA) | Rated insulated level(kV) | |||
|---|---|---|---|---|---|---|---|
| 0.2 | 0.5 | 1 | 3 | ||||
| JSJW-6 | 6000/100 | 60 | 80 | 150 | 320 | 640 | 7.2/32/60 |
| JSJW10 | 10000/100 | 60 | 120 | 200 | 480 | 960 | 12/42/75 |
| JSJW-11 | 11000/100 | ||||||
| JSJW-12 | 12000/100 | ||||||
Installation & Wiring
Installation Diagram
The JSJW-6 and JSJW-10 voltage transformers can be installed in either stand (vertical) or lying (horizontal) configurations. Stand-type units are mounted via four Φ18 holes at the base, with mounting references of 248mm for JSJW-6 and 320mm for JSJW-10. Lying-type installation is used where vertical clearance is limited or site layout requires a horizontal tank orientation.
Wiring Diagram
The wiring diagram shows standard terminal markings for three-phase oil-immersed voltage transformers. Primary windings are connected to system voltage (e.g., 6kV or 10kV), while secondary windings provide output voltages such as 100V, 100/√3 V, or 100/3 V for metering, measurement, or protection circuits. The da/dn open-delta terminals are provided for residual voltage output used in earth-fault detection schemes. Ensure correct polarity and phase sequence during connection.
Selection & FAQs
Selection Guide
- Select the voltage ratio and connection scheme together. Distinguish line-to-line 6000/100V or 10000/100V service from phase-to-earth √3 ratios with a 100/3V residual winding.
- Choose JSJW-6 or JSJW-10 from insulation coordination. Published levels are 7.2/32/60kV and 12/42/75kV respectively; 11kV/12kV variants are by agreement.
- Match accuracy class to rated output. Use the model-specific 0.2, 0.5, 1, 3 or 6P value and do not confuse the 640VA/960VA limit with accuracy-rated burden.
- Define the residual-voltage circuit. Confirm da/dn voltage, open-delta connection, relay burden, grounding and system neutral conditions.
- Approve oil and installation details. Resolve oil specification, sealed-tank maintenance, vertical/horizontal orientation, four Ø18 holes, lifting, clearances, fuses, phase sequence and terminal diagram.
Frequently Asked Questions
Q1: Can the JSJW-6 be installed in outdoor environments?
No, this voltage transformer requires indoor installation. The environment must be free from severe vibration, shock, and corrosive gases. Contact us for outdoor-rated alternatives.
Q2: Why does the class 3 accuracy offer the highest output?
Class 3 accuracy permits a higher thermal burden limit, supporting up to 480VA for the JSJW-10. Lower classes like 0.2 and 0.5 restrict outputs to 60VA and 120VA. Confirm your burden requirements with our engineering team.
Q3: What is the maximum altitude for operating this 10kV PT?
The maximum installation altitude must not exceed 1000 meters above sea level. Higher altitudes require derating or special factory design. Please specify your site elevation during inquiry.
Q4: Are these three-phase transformers compliant with international PT standards?
Yes, the JSJW-6 and JSJW-10 models comply with international PT standards. They feature rated insulated levels up to 12/42/75kV for 10kV systems. Request specific compliance certificates for your region.
Q5: How can I request custom rated voltages for non-standard systems?
Custom rated voltages are subject to factory confirmation. Standard models are 6000/100V and 10000/100V. Contact our sales team with your specific system parameters for feasibility.
Q6: When should I choose the JSJW-10 over the JSJW-6 model?
Choose the JSJW-10 for 10kV systems requiring up to 480VA at class 3 accuracy. The JSJW-6 is designed for 6kV networks with a 320VA class 3 output. Consult our engineers for system matching.
Q7: Which power systems utilize the JSJW-10 three-phase voltage transformer?
This transformer is applied in 10kV indoor power distribution networks. It provides voltage signals for measurement, protection, and control circuits. Contact the manufacturer for detailed application cases.