Product Overview
The JDZ11-10A/185 / UNZ10 voltage transformer is an indoor single-phase epoxy cast-resin voltage transformer for medium-voltage switchgear, metering panels and protection circuits. It is used for voltage measurement, electric energy metering, voltage monitoring, relay protection and automatic control signal conversion in 50Hz or 60Hz power systems.
This page should be differentiated from the previous JDZ(X)7-10 / UNEZ7 page. JDZ11-10A/185 is a compact, fully enclosed epoxy vacuum cast-resin structure. The number 185 refers to the cast-resin body width in millimetres, which is an important selection point for cabinet installation and replacement projects.
The product is equivalent or closely related to UNZ10 for the same indoor fully enclosed cast-resin voltage transformer application. For international pages, the voltage class should cover 6kV, 10kV, 11kV and 12kV class. Final voltage ratio, insulation level, accuracy class and wiring method shall be confirmed by project specification and approved nameplate.
Product Type
| Item | Specification |
|---|---|
| Product name | Indoor Fully Enclosed Epoxy Cast-Resin Voltage Transformer |
| Model series | JDZ11-10A/185 / JDZ11-10/185 / JDZX11-10/185 / UNZ10 |
| Structure | Single-phase, indoor, fully enclosed epoxy vacuum cast-resin insulation |
| Casting width | 185mm body-width reference for installation and replacement selection |
| Voltage class | 6kV, 10kV, 11kV and 12kV class medium-voltage systems |
| 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 : 0.1/3 by project requirement |
| Accuracy classes | 0.2, 0.5 for metering; 3P / 6P for protection or residual-voltage output |
| Rated insulation level | 7.2/32/60kV for 6kV class; 12/42/75kV for 10kV, 11kV and 12kV class |
| Maximum output | 350VA reference |
Product Display
Applications
- 6kV, 10kV, 11kV and 12kV class indoor medium-voltage switchgear
- Electric energy metering and voltage measurement circuits
- Relay protection and voltage monitoring circuits
- Automatic control equipment and signal acquisition circuits
- Phase-to-earth voltage measurement using JDZX-type configuration
- Phase-to-phase voltage measurement using JDZ-type configuration
- Replacement projects requiring 185mm cast-resin body width
Features
- 185mm casting-width reference: The 185 dimension is the core mechanical feature for cabinet fit and replacement comparison.
- Fully enclosed vacuum casting: All windings are completely cast in epoxy resin for insulation stability, moisture resistance and mechanical strength.
- Compact and lightweight structure: The product occupies limited cabinet space and is suitable for compact indoor switchgear.
- Clear terminal marking: Primary terminals such as A and N, and secondary terminals such as a and n, are marked clearly on the cast body.
- Metering and protection outputs: The product supports 0.2/3P, 0.2/6P, 0.5/3P and 0.5/6P combinations.
- International voltage coverage: The page can include 6kV, 10kV, 11kV and 12kV class wording for IEC-oriented export projects.
Working Principle
The JDZ11-10A/185 voltage transformer operates by electromagnetic induction. The primary winding is connected to the medium-voltage system, and the secondary winding outputs a reduced standard voltage signal for meters, relays and control devices. Epoxy cast-resin insulation isolates the secondary low-voltage circuit from the primary medium-voltage circuit.
The product can be used as a single unit or in a group according to the wiring scheme. JDZ-type units are used for phase-to-phase voltage measurement, while JDZX-type units are used for phase-to-earth voltage measurement and residual-voltage output.
Service Conditions
- Installation location: indoor medium-voltage switchgear
- Rated frequency: 50Hz / 60Hz
- Altitude: not exceeding 3000m unless otherwise agreed
- Ambient temperature: -25°C to +40°C
- Relative humidity: not more than 65% at 20°C reference
- Pollution class: suitable for Class II pollution level unless otherwise specified
- Installation environment should be free from corrosive gas, severe vibration, conductive dust and abnormal condensation.
Model Designation
| Code | Meaning |
|---|---|
| J | Voltage transformer / potential transformer |
| D | Single-phase structure |
| Z | Epoxy resin cast insulation |
| X | Phase-to-earth / residual-voltage function reference depending on model configuration |
| 11 | Design sequence code for fully enclosed cast-resin structure |
| 10A | 10kV class model reference and structure variant |
| 185 | Cast-resin body width dimension reference in mm |
Technical Data
| Item | Specification |
|---|---|
| Rated voltage class | 6kV, 10kV, 11kV and 12kV class indoor systems |
| Rated insulation level | 7.2/32/60kV for 6kV class; 12/42/75kV for 10kV, 11kV and 12kV class |
| Rated frequency | 50Hz / 60Hz |
| Ambient temperature | -25°C to +40°C |
| Core material | High-quality silicon steel sheet core |
| Insulation structure | All windings vacuum cast in epoxy resin |
| Rated voltage ratio | 6/√3 : 0.1/√3 : 0.1/3; 10/√3 : 0.1/√3 : 0.1/3; 11/√3 : 0.11/√3 : 0.1/3 by agreement |
| Accuracy class | 0.2 / 3P, 0.2 / 6P, 0.5 / 3P, 0.5 / 6P |
| Maximum output | 350VA reference |
| Applicable standards | IEC 61869-3, IEC 61869-1, IEC 60044-2, GB/T 20840.3-2013, GB/T 20840.1-2010 and project-specific requirements |
Selection Table
| Model | Rated
Voltage |
Rated
Insulation |
Accuracy
Class |
Maximum Output |
|---|---|---|---|---|
| JDZX11-10/185 | 6/√3 : 0.1/√3 : 0.1/3 6.3/√3 : 0.1/√3 : 0.1/3 |
7.2 / 32 / 60kV | 0.2 / 3P: 15 / 60VA 0.2 / 6P: 15 / 60VA 0.5 / 3P: 30 / 60VA 0.5 / 6P: 30 / 60VA |
350VA |
| JDZX11-10/185 UNZ10 |
10/√3 : 0.1/√3 : 0.1/3 11/√3 : 0.11/√3 : 0.1/3 |
12 / 42 / 75kV | 0.2 / 3P: 15 / 60VA 0.2 / 6P: 15 / 60VA 0.5 / 3P: 30 / 60VA 0.5 / 6P: 30 / 60VA |
|
| JDZ11-10A/185 UNZ10 |
10 / 0.1 11 / 0.11 by agreement 12 / 0.11 by agreement |
12 / 42 / 75kV | 0.2: 15VA 0.5: 30VA 1.0: by agreement 3.0: by agreement |
350VA |
Note: Rated output and its relative accuracy class should be selected as matched options. Parameters beyond the catalogue range may be determined by technical agreement between manufacturer and purchaser.
Wiring Options
| Wiring Method | Configuration | Application Note |
|---|---|---|
| Single-phase phase-to-earth | JDZX type with A / N primary terminal arrangement | Used for phase voltage measurement and residual-voltage applications. |
| Single-phase phase-to-phase | JDZ type with phase-to-phase voltage ratio | Used for line voltage measurement, metering or protection input. |
| V-V connection | Two single-phase voltage transformers used as a group | Used for three-phase voltage measurement with two VT units. |
| Y / Y / open-delta | Three single-phase VTs with residual-voltage secondary circuit | Used where earth-fault detection or residual-voltage protection is required. |
All windings are completely vacuum cast in epoxy resin, which protects the winding from moisture and improves resistance to impact and mechanical stress. Typical terminal marking includes A / N for the primary winding and a / n for the secondary winding. Where residual-voltage output is supplied, terminals may include da / dn according to the approved wiring diagram.
| Terminal | Function | Engineering Note |
|---|---|---|
| A / N | Primary winding terminals | Clearly marked on the cast body for phase-to-earth connection. |
| A / B | Primary phase-to-phase terminals | Used for JDZ phase-to-phase voltage transformer applications. |
| a / n | Secondary voltage output | Connected to meters, relays, monitoring devices or control equipment. |
| da / dn | Residual-voltage output | Used when residual-voltage or earth-fault detection is required. |
| Grounding bolt | Protective grounding | Located near the grounding mark on the clamp or mounting structure. |
Dimensions
| Dimension Item | Reference Value | Engineering Note |
|---|---|---|
| Cast-resin body width | 185mm | Key model dimension for JDZ11-10A/185 selection. |
| Overall length | 350mm reference | Main length reference from outline drawing. |
| Body length | 290mm reference | Used for cabinet layout and replacement comparison. |
| Overall height | 269 ± 3mm reference | Confirm top terminal clearance before installation. |
| Top terminal spacing | 148 ± 0.5mm reference | Used for primary terminal clearance and connection planning. |
| Mounting base width | 185mm reference | Consistent with the compact 185mm structure. |
| Weight | Approx. 25.5kg reference | Actual value depends on final ratio and configuration. |
Standards and Compliance
The JDZ11-10A/185 / UNZ10 series voltage transformer can be specified according to IEC 61869-3 for inductive voltage transformers and IEC 61869-1 for general instrument transformer requirements. Catalogue and legacy documentation may also reference IEC 60044-2, GB/T 20840.3-2013 and GB/T 20840.1-2010.
Installation and Dimensions
The product is installed inside indoor switchgear using the lower mounting bracket or base plate. Before production, confirm the 185mm casting-width requirement, top terminal clearance, secondary terminal direction, grounding bolt position, mounting hole distance and wiring method.
Safety Notes
- Confirm voltage class, voltage ratio, insulation level, accuracy class and rated output before production.
- Confirm whether JDZ, JDZX, JDZF or JDZX-G structure is required according to wiring and residual-voltage requirements.
- Secondary circuits of voltage transformers shall not be short-circuited during operation.
- Secondary circuits should be protected by suitable fuses or miniature circuit breakers.
- Before maintenance, de-energize the primary circuit and follow lockout/tagout safety procedures.
- The grounding bolt should be connected according to the project electrical safety practice.
Selection Guide
- Confirm structure: Use JDZ11-10A/185 or UNZ10 when a compact fully enclosed single-phase VT with 185mm casting width is required.
- Confirm voltage class: Select 6kV, 10kV, 11kV or 12kV class according to system voltage and insulation requirement.
- Select connection type: Use JDZ for phase-to-phase applications and JDZX for phase-to-earth or residual-voltage applications.
- Select voltage ratio: Use 10/√3 : 0.1/√3 : 0.1/3 for phase voltage applications, or 10/0.1 for line voltage applications.
- Define accuracy: Use 0.2 or 0.5 for metering, and 3P or 6P for protection or residual-voltage functions.
- Check burden: Ensure the total burden of meters, relays and wiring does not exceed the rated output.
- Approve dimensions: Confirm casting width, mounting holes, terminal clearance and grounding position before production.