Overview
The JDZ9-10 and JDZX(F)9-10G series are single-phase, dual-winding electromagnetic voltage transformers designed for accurate voltage measurement, energy metering, and relay protection in 6-12 kV indoor AC power systems. Operating on Faraday’s law of electromagnetic induction, they deliver galvanically isolated secondary signals proportional to the primary voltage, ensuring safe and reliable system monitoring.
These units feature fully enclosed epoxy resin cast construction, providing superior dielectric strength, moisture resistance, and mechanical robustness for long-term indoor switchgear operation. The compact post-type design enables easy integration into space-constrained medium-voltage panels while maintaining required electrical clearances.
Key Ratings Snapshot
| Parameter | Value |
|---|---|
| System voltage class | 10 kV (6 kV supported) |
| Rated frequency | 50 Hz (60 Hz on request) |
| Rated secondary voltage | 100 V or 100/â3 V |
| Accuracy classes | 0.2 / 0.5 (metering), 3P (protection) |
| Rated burden | Per winding, as specified (VA) |
| Burden power factor | cos phi = 0.8 (lagging) |
| Insulation level | Per standard (e.g., 12/42/75 kV) |
| Partial discharge | Per GB 1207-1997 if specified |
| Configuration variants | JDZ9-10 (basic), JDZX(F)9-10G (with residual winding) |
| Applicable standards | IEC 61869-3, GB/T 20840.3 |
Model Designation
- J : Voltage transformer (VT/PT)
- D : Single-phase configuration
- Z : Indoor support (pillar) type
- X : With residual voltage winding (earth fault detection)
- (F) : Variant designation
- 9 : Design code
- 10 : Voltage class (kV)
- G : Enhanced or modified variant
Construction
The transformer employs a high-permeability silicon steel magnetic core with precision-wound primary and secondary coils, fully encapsulated in epoxy resin. This cast construction ensures excellent insulation integrity, resistance to thermal cycling, humidity, and contamination, making it ideal for indoor environments. The post-type mounting base includes four bolt holes for secure installation in switchgear cubicles.
An integrated secondary terminal box allows dual-side cable entry for flexible wiring. Terminal markings follow standard polarity conventions (A/a positive simultaneously). The design is maintenance-free under normal conditions, requiring only periodic surface cleaning to sustain performance over decades of service.
Technical Parameters
Service Conditions
- Installation environment: Indoor only
- Altitude: <= 1000 m (high-altitude variants on request)
- Ambient temperature: -5 deg C to +40 deg C
- Relative humidity: <= 85% at +20 deg C
- Pollution degree: Class II or III per IEC 60664
- Environmental conditions: Free from corrosive gases, dust, explosive media; no severe vibration
- Rated frequency: 50 Hz (60 Hz available upon request)
Technical Data
| Type | Rated Voltage Ratio (V) |
Accuracy Class & Rated Output (VA) |
Limit Output (VA) |
Rated Insulation Level (kV) |
|||
|---|---|---|---|---|---|---|---|
| 0.2 | 0.5 | 1 | 6P | ||||
| JDZ9-10 | 10000/100 | 30 | 100 | 200 | 600 | 12/42/75 | |
| JDZF9-10 | 10000/100/100 | 20 | 20 | 80 | 2 x 300 | 12/42/75 | |
| JDZX9-10G | 10000/
3/100/√3/100/3
|
20 | 30 | 100 | 100 | 500 | 12/42/75 |
Installation & Wiring
Installation Diagram
Mount the transformer vertically using the four base plate bolt holes. Primary terminals connect directly to the busbar or switchgear conductor. Secondary wiring is routed through the integrated terminal box, which supports cable entry from either side. Maintain minimum clearance distances for insulation, heat dissipation, and safety compliance as per local regulations.
Outline Dimensions
| Model | Height (mm) | Base Width (mm) | Bolt Hole Pattern (mm) | phi Mounting Holes (mm) |
|---|---|---|---|---|
| JDZ9-10 / JDZX9-10G | Approx. 380 | Approx. 160 | 120 x 120 | 12 |
| JDZ9-6 / JDZX9-6G | Approx. 320 | Approx. 140 | 100 x 100 | 10 |
| JDZ9-3 / JDZX9-3G | Approx. 260 | Approx. 120 | 80 x 80 | 8 |
Selection & FAQs
Selection Guide
- Determine primary voltage based on system nominal (e.g., 10 kV line-to-ground or line-to-line).
- Select secondary voltage: 100 V for phase-to-phase systems, 100/â3 V for phase-to-ground applications.
- Specify accuracy class per function: 0.2 or 0.5 for revenue metering; 3P or 6P for protection relays.
- Calculate total burden (VA) for each winding including meters, relays, and wiring impedance losses.
- Choose JDZX(F)9-10G if earth fault detection via residual voltage winding is required.
Frequently Asked Questions
Q1: Can this resin insulated transformer be installed outdoors?
No, it is strictly designed for indoor installation only. The enclosure requires an environment free from corrosive gases and severe vibration. Contact us for outdoor-rated variants.
Q2: Which accuracy class is suitable for protection relays?
Select the 6P accuracy class for protection applications. This ensures reliable performance during fault conditions up to the rated limit output. Confirm specific burden requirements with our engineering team.
Q3: What is the rated insulation level for 10kV models?
The standard rated insulation level is 12/42/75 kV for 10kV systems. This covers rated short-duration power frequency and lightning impulse withstand voltages. Factory test reports are provided upon request.
Q4: Are 60Hz variants available for export projects?
Yes, 60Hz models are available upon request alongside the standard 50Hz versions. Specify your target grid frequency during the inquiry phase. We will confirm technical feasibility and lead time.
Q5: Can these transformers operate at altitudes above 1000 meters?
Standard models are rated for altitudes up to 1000 meters. High-altitude variants with enhanced insulation can be manufactured upon request. Please provide the exact site elevation for custom design.
Q6: What applications suit the JDZF9-10 voltage transformer?
This model features a 10000/100/100V ratio, making it ideal for indoor switchgear requiring measurement and residual voltage detection. It supports class 0.2 and 0.5 for precision metering. Contact sales for single-line diagram review.
Q7: How much burden can the JDZ9-10 handle at class 0.5?
The JDZ9-10 supports a rated output of 100 VA at the 0.5 accuracy class. Ensure connected metering devices do not exceed the 600 VA limit output. Contact our engineers for burden calculations.