Overview
The JDZ(X)7-10 / UNEZ7-6 / UNEZ7-10 is a single-phase indoor epoxy cast-resin voltage transformer designed for 6kV, 10kV, 11kV, and 12kV class medium-voltage systems. It features fully cast epoxy resin insulation, providing high dielectric strength, mechanical robustness, and moisture resistance suitable for indoor switchgear environments.
This voltage transformer supports accuracy classes of 0.2, 0.5, 1.0, and 3.0 for metering and measurement, with protection classes 3P or 6P available per project requirements. It is commonly used in voltage measurement, energy metering, relay protection, and automatic control circuits within V-V or Y-Δ wiring configurations. The design complies with IEC standards and is adaptable to international projects requiring 11kV or 12kV class documentation.
Key Ratings Snapshot
| Parameter | Rating |
|---|---|
| Voltage class | 6kV, 10kV, 11kV, 12kV |
| Rated frequency | 50Hz / 60Hz |
| Rated voltage ratio | 6/√3 : 0.1/√3 : 0.1/3; 10/√3 : 0.1/√3 : 0.1/3; 11/√3 : 0.11/√3 : 0.11/3 |
| Accuracy classes | 0.2, 0.5, 1.0, 3.0 (metering); 3P, 6P (protection) |
| Insulation level (6kV) | 7.2/32/60kV |
| Insulation level (10–12kV) | 12/42/75kV |
| Maximum output | 350VA |
| Phase configuration | Single-phase |
| Insulation type | Epoxy cast-resin |
| Installation | Indoor switchgear |
| Ambient temperature | -25°C to +40°C |
| Typical applications | Metering, protection, control, voltage monitoring |
Construction
The JDZ(X)7-10 / UNEZ7-6 / UNEZ7-10 features a monolithic epoxy cast-resin body that fully encapsulates the magnetic core and windings. This construction provides excellent electrical insulation, high mechanical strength, and resistance to humidity and contamination, making it suitable for indoor medium-voltage switchgear. The primary winding is connected directly to the system voltage, while the secondary windings deliver standardized low-voltage outputs for metering and protection devices. Secondary terminals are arranged on the front face with a protective cover to facilitate safe and convenient wiring during installation and maintenance. The compact, sealed design ensures long-term reliability under normal indoor service conditions without the need for oil or gas insulation.
Technical Parameters
Service Conditions
- Ambient temperature: -25°C to +40°C
- Installation environment: Indoor
Technical Parameters
The JDZ(X)7-10 / UNEZ7-6/10 series are indoor single-phase epoxy cast-resin inductive voltage transformers designed for 6kV, 10kV, 11kV, and 12kV class systems. They operate within an ambient temperature range of -25°C to +40°C, comply with IEC 61869-3, IEC 61869-1, GB/T 20840.3-2013, and GB/T 20840.1-2010 standards, and support rated outputs up to 350VA.
| Type | Voltage Ratio(kV) |
Rated insulation(kV) |
Accuracy class / Rated output (VA) |
Max. output (VA) |
|---|---|---|---|---|
| JDZ11-10/185 | 6/√3:0.1/√3:0.1/3 6.3/√3:0.1/√3:0.1/3 |
7.2/32/60 | 0.2/3P—15/60 0.2/6P—15/60 |
350 |
| JDZ11-10/185 | 10/√3:0.1/√3:0.1/3 11/√3:0.11/√3:0.1/3 |
12/42/75 | 0.5/3P—30/60 0.5/6P—30/60 |
Installation & Wiring
Installation Diagram
Wiring Diagram
The JDZ(X)7-10 and UNEZ7-6/10 indoor epoxy cast-resin voltage transformers are installed within indoor switchgear using the base mounting holes as detailed in the outline drawing. Prior to cabinet fabrication, verify clearances for top terminals, secondary terminal orientation, grounding point location, mounting hole spacing, wiring configuration, and adequate access space for maintenance activities. For V-V or Y-Δ wiring configurations, confirm the required number of VT units and terminal connections against the approved wiring diagram.
Selection & FAQs
Selection Guide
- Select JDZ(X)7-10 for single-phase indoor applications requiring standard low-voltage output for metering, protection, or control.
- Choose JDZX over JDZ if residual-voltage or auxiliary winding functionality is needed—confirm terminal diagrams before ordering.
- Use V-V wiring with two units or Y-Δ wiring with three units based on system voltage, grounding mode, and protection requirements.
- Verify voltage class (10kV, 11kV, or 12kV) and insulation level according to project specifications, even though the base model is labeled JDZ(X)7-110.
- Ensure secondary circuits are never short-circuited during operation; include appropriate secondary protection devices as per design.
Frequently Asked Questions
Q1: Can this voltage transformer be used in 11kV switchgear?
Yes. The JDZ(X)7-10 series is designed for 6kV, 10kV, 11kV, and 12kV class systems. Please specify your exact system voltage during inquiry.
Q2: Which accuracy class is suitable for protective relaying?
Select the 3P or 6P accuracy class for protection applications. These classes support rated outputs of 60VA. Contact us to verify specific relay burden requirements.
Q3: What are the ambient temperature limits for indoor installation?
The operating ambient temperature range is -25°C to +40°C. It is strictly designed for indoor environments only. Confirm your specific site conditions with our engineering team.
Q4: Can we request a customized rated output beyond 350VA?
Yes, custom outputs are possible. If your required data exceeds the standard 350VA maximum output, it is subject to a specific agreement between manufacturer and purchaser.
Q5: Which international standards does this epoxy cast-resin transformer comply with?
The series complies with IEC 61869-3, IEC 61869-1, GB/T 20840.3-2013, and GB/T 20840.1-2010 standards. Request the type test reports for your specific project requirements.
Q6: What type of voltage transformer is the UNEZ7-6/10 model?
It is an indoor single-phase epoxy cast-resin inductive voltage transformer. It is primarily applied in 6kV to 12kV power distribution systems for voltage measurement and protection.
Q7: How are the voltage ratios configured for the 10kV models?
Standard 10kV models feature ratios like 10/√3 : 0.1/√3 : 0.1/3. Please provide your system grounding details so we can confirm the exact ratio configuration.