Overview
The JDZJ series single-phase epoxy resin voltage transformers (including JDZJ-3, JDZJ-6, and JDZJ-10 models) are precision electromagnetic devices engineered for accurate voltage measurement, energy metering, and relay protection in 3â10 kV indoor AC power systems operating at 50 Hz. Based on Faraday’s law of electromagnetic induction, these transformers deliver galvanically isolated secondary voltages proportional to the primary input, ensuring reliable performance in medium-voltage distribution networks.
Epoxy resin cast construction provides excellent moisture resistance, mechanical strength, and long-term insulation stability, making these units ideal for compact indoor switchgear installations requiring dual functionality for both metering and protection circuits.
Key Ratings Snapshot
| Parameter | Value |
|---|---|
| System voltage class | 3 kV, 6 kV, or 10 kV (indoor) |
| Rated frequency | 50 Hz |
| Voltage ratio | 3000/â3:100/â3:100/3 6000/â3:100/â3:100/3 10000/â3:100/â3:100/3 |
| Accuracy classes | 0.5 / 1 / 3 |
| Rated output (VA) | Up to 80 (0.5), 150 (1), 300 (3) per model |
| Maximum output (VA) | 200 (JDZJ-3), 400 (JDZJ-6), 500 (JDZJ-10) |
| Insulation level (kV) | 3.5/23/40, 6.9/32/60, 12/42/75 |
| Construction | Epoxy resin cast, single-phase, dual winding |
| Seismic capacity | 0.4g (intensity IX) |
| Applicable standards | GB 1207 / IEC 61869-3 / IEC 61869-1 |
Model Designation
- J: Voltage transformer (VT)
- D: Single-phase configuration
- Z: Indoor support (pillar) type
- J: Epoxy resin cast insulation structure
- 3 / 6 / 10: Voltage class in kV
- (W): Optional enhanced environmental variant
Construction
The JDZJ series features a fully enclosed epoxy resin cast design with a laminated ring-type magnetic core and concentrically arranged primary and secondary windings. This construction ensures superior dielectric strength, resistance to humidity and contamination, and robust mechanical integrity for long-term indoor service. The compact vertical post-type form factor optimizes space in switchgear panels while maintaining required electrical clearances.
Dual secondary windings allow simultaneous connection to metering and protection circuits without performance compromise. All internal components are completely encapsulated in high-grade epoxy resin, eliminating air gaps and preventing partial discharge under normal operating conditions.
Technical Parameters
Service Conditions
- Installation environment: Indoor (moderate pollution)
- Altitude: <= 1000 m above sea level
- Ambient temperature: -5 deg C to +40 deg C
- Relative humidity: <= 85% at +20 deg C
- Seismic capacity: 0.4g horizontal acceleration
- Environmental conditions: Free from corrosive gases, explosive media, severe vibration or shock
Technical Data
| Parameter | JDZJ-3(W) | JDZJ-6(W) | JDZJ-10(W) |
|---|---|---|---|
| Rated voltage ratio | 3000/â3/100/â3/100/3 | 6000/â3/100/â3/100/3 | 10000/â3/100/â3/100/3 |
| Rated frequency (Hz) | 50 | 50 | 50 |
| Rated output (VA) 0.5 class 1 class 3 class |
30 50 80 |
50 80 200 |
80 150 300 |
| Maximum output (VA) | 200 | 400 | 500 |
| Insulation level (kV) Um / Ud / Up |
3.5 / 23 / 40 | 6.9 / 32 / 60 | 12 / 42 / 75 |
| Burden power factor | cos phi = 0.8 (lagging) | cos phi = 0.8 (lagging) | cos phi = 0.8 (lagging) |
Installation & Wiring
Installation Diagram
Primary terminals (A, X) are located at the top of the unit for connection to the medium-voltage busbar. Secondary terminals (a, x for each winding group) are accessible via screw terminals at the base. The transformer is mounted vertically using the base fixing holes. Ensure proper grounding of one secondary terminal per applicable standards.
Outline Dimensions
| Model | Total Height (mm) | Base Width (mm) | Mounting Hole Spacing (mm) | phi Primary Terminal (mm) |
|---|---|---|---|---|
| JDZJ-3(W) | 320 | 120 | 90 | 12 |
| JDZJ-6(W) | 410 | 140 | 110 | 14 |
| JDZJ-10(W) | 520 | 160 | 130 | 16 |
Selection & FAQs
Selection Guide
- Select voltage class (3/6/10 kV) matching your system nominal voltage.
- Choose accuracy class 0.5 or 1 for revenue metering; class 3 is suitable for protection relays.
- Verify total secondary burden (VA) does not exceed rated output at specified accuracy class.
- Confirm insulation level meets local switchgear dielectric coordination requirements.
- Specify (W) variant only if enhanced pollution or environmental performance is needed.
Frequently Asked Questions
Q1: What is the highest system voltage for the JDZJ-10W voltage transformer?
The JDZJ-10(W) model supports a highest equipment voltage (Um) of 12 kV. It features an insulation level of 12/42/75 kV. Please confirm your exact system parameters with our engineers.
Q2: Can this cast epoxy resin voltage transformer be installed outdoors?
No, it is strictly rated for indoor installation in moderate pollution environments. The operating ambient temperature must remain between -5°C and +40°C. Contact us for outdoor-rated alternatives.
Q3: Which accuracy class provides the highest rated burden for the 10kV model?
The 3-class accuracy offers the highest rated output at 300 VA for the JDZJ-10(W) model. The maximum output capacity reaches 500 VA. Specify your burden requirements during ordering.
Q4: What routine factory tests are performed on these voltage transformers?
Routine factory tests are subject to confirmation based on your specific order requirements. Standard checks typically include ratio and insulation resistance verification. Contact us for the detailed test report template.
Q5: Can this 50Hz single-phase transformer be customized for 60Hz power systems?
The standard JDZJ series is rated for 50Hz operation. Custom 60Hz configurations are available subject to factory engineering confirmation. Please provide your exact frequency and voltage ratio requirements.
Q6: What is the primary application of this single-phase voltage transformer?
It is primarily used for voltage measurement and relay protection in indoor 3kV to 10kV switchgear. The cast epoxy resin ensures high dielectric strength. Contact sales for project-specific applications.
Q7: How does this epoxy voltage transformer perform in high-vibration environments?
It is designed for environments free from severe vibration or shock, with a seismic capacity of 0.4g horizontal acceleration. For high-vibration sites, please contact our technical team for specialized solutions.