Product Overview
The JDZ(X)8-3 / JDZ(X)8-6 / JDZ(X)8-10 indoor epoxy cast-resin voltage transformer, also called a potential transformer (PT), is a single-phase fully enclosed PT designed for voltage measurement, energy metering, voltage monitoring and relay protection in medium-voltage power systems. It is suitable for 50Hz or 60Hz systems and can be specified for 3kV, 6kV, 10kV, 11kV and 12kV class indoor switchgear projects when the voltage ratio, insulation level and project standard are confirmed.
This product should be differentiated from JSJW oil-immersed PTs and JSZW three-phase PTs. The JDZ(X)8 series uses a single-phase epoxy cast-resin fully enclosed structure, with the iron core and windings cast together into one compact body. It is small, lightweight and suitable for flexible outlet arrangements, including single-phase line wiring, two-PT three-phase wiring and three-PT wiring with residual-voltage output.
Product Type
| Item | Specification |
|---|---|
| Product name | Indoor Single-Phase Epoxy Cast-Resin Voltage Transformer / Potential Transformer |
| Model series | JDZ8-3 / JDZ8-6 / JDZ8-10 / JDZX8-3 / JDZX8-6 / JDZX8-10 |
| Transformer type | Single-phase, fully enclosed, epoxy cast-resin inductive PT |
| Structure | Iron core and windings cast together in epoxy resin; outlet box for secondary terminals |
| Rated voltage class | 3kV, 6kV, 10kV, 11kV and 12kV class indoor systems by project confirmation |
| Rated voltage ratio | 3000/100V, 6000/100V, 10000/100V, or 10000/√3 : 100/√3 : 100/3 depending on model and wiring scheme |
| International ratio options | 11000/110V or 11000/√3 : 110/√3 : 110/3 by agreement for 11kV systems |
| Rated frequency | 50Hz / 60Hz |
| Accuracy classes | 0.2, 0.5, 1 and 6P |
| Residual-voltage winding | Available on JDZX type for open-delta residual-voltage protection schemes |
| Limit output | 300VA reference |
| Rated insulation level | 3.6/25/40kV for 3kV class; 7.2/32/60kV for 6kV class; 12/42/75kV for 10kV, 11kV and 12kV class |
| Typical use | Voltage metering, voltage monitoring, control signal acquisition and relay protection |
| Applicable standards | IEC 61869-3, IEC 61869-1, IEC 60044-2, GB1207-1997 and project-specific requirements |
Product Display
Model Designation
- J: Voltage transformer / potential transformer
- D: Single-phase structure
- Z: Epoxy cast-resin insulation
- X: Residual-voltage winding / phase-to-earth PT structure reference
- 8: Design sequence code
- 3 / 6 / 10: Catalogue voltage grade reference in kV
- JDZ8: Basic single-phase PT for phase-to-phase or line voltage measurement
- JDZX8: PT with residual-voltage winding, suitable for phase-to-earth and open-delta protection schemes
Service Conditions
- Installation location: Indoor medium-voltage switchgear
- Rated frequency: 50Hz / 60Hz
- Ambient temperature: -5°C to +40°C, or project-specific indoor service condition
- Altitude: Standard installation up to 1000m unless otherwise agreed
- Humidity and pollution: Indoor clean electrical room or switchgear compartment, free from severe condensation and conductive dust
- Installation site: Free from corrosive gas, explosive medium, severe vibration and insulation-damaging chemical contamination
- Special environments: Tropical, coastal, high-altitude or high-humidity projects require confirmation of creepage distance, insulation coordination and anti-condensation measures
Construction
The JDZ(X)8 series is a fully enclosed epoxy cast-resin PT. The iron core and windings are cast together into a single compact body, which improves mechanical strength and helps protect the internal insulation from moisture and pollution. The secondary outlet is wrapped by a terminal box, and the outgoing lines can be arranged in different directions according to the wiring layout.
The product is designed for flexible single-phase PT schemes. JDZ8 models are suitable for basic voltage transformation, while JDZX8 models include residual-voltage winding functions for protection applications. This makes the series suitable for single-phase line wiring, two-PT three-phase wiring and three-PT wiring with residual-voltage output.
Applications
- 3kV, 6kV, 10kV, 11kV and 12kV class indoor medium-voltage switchgear
- Voltage measurement and electric energy metering circuits
- Voltage monitoring, signal acquisition and automatic control systems
- Relay protection circuits requiring standard PT secondary voltage
- Single-phase line measurement using one JDZ8 PT
- Three-phase voltage measurement using two JDZ8 PTs
- Residual-voltage and earth-fault detection using three JDZX8 PTs
Technical Data
The following technical table is organized from the catalogue data and written in international PT terminology. For 11kV / 12kV class projects, the final ratio and insulation level should be confirmed by the local grid standard and project specification.
| Model | Rated
Voltage |
Accuracy
Class |
Limit Output |
Rated
Insulation |
|---|---|---|---|---|
| JDZ8-3 | 3000 / 100V | 0.2: 15VA 0.5: 30VA 1: 60VA 6P: 50VA |
300VA | 3.6 / 25 / 40kV |
| JDZ8-6 | 6000 / 100V | 7.2 / 32 / 60kV | ||
| JDZ8-10 | 10000 / 100V 11000 / 110V by agreement |
12 / 42 / 75kV | ||
| JDZX8-3 | 3000 / √3 : 100 / √3 : 100 / 3 | 3.6 / 25 / 40kV | ||
| JDZX8-6 | 6000 / √3 : 100 / √3 : 100 / 3 | 7.2 / 32 / 60kV | ||
| JDZX8-10 | 10000 / √3 : 100 / √3 : 100 / 3 11000 / √3 : 110 / √3 : 110 / 3 by agreement |
12 / 42 / 75kV |
Note: Rated output and accuracy class shall be selected as matched options. Final data shall follow the approved nameplate, routine test report, drawing or technical agreement.
Wiring Options
The JDZ(X)8 series supports several single-phase PT wiring schemes. The JDZ8 type is suitable for basic single-phase or phase-to-phase voltage measurement. The JDZX8 type includes a residual-voltage winding and can be used in three-phase open-delta protection schemes.
| Wiring Method | Configuration | Application Note |
|---|---|---|
| Single-phase line | One JDZ8 PT connected for single-phase voltage measurement | Used for simple voltage monitoring, metering reference or control signal input. |
| Two-PT three-phase wiring | Two JDZ8 PTs connected for three-phase line voltage measurement | Used where simplified three-phase voltage measurement is required. |
| Three-PT wiring | Three JDZX8 PTs connected in phase-to-earth arrangement | Used for three-phase phase voltage measurement and residual-voltage protection. |
| Residual-voltage output | Open-delta output from JDZX8 residual-voltage winding | Used for earth-fault detection and relay protection circuits. |
Installation & Safety Notes
Dimensions
| Dimension Item | Reference Value | Engineering Note |
|---|---|---|
| Overall length | 370mm reference | Main footprint length for switchgear layout. |
| Base length | 330mm / 303mm reference | Used for mounting-hole and base-plate layout confirmation. |
| Body width | 160mm reference | Compact cast-resin body width for cabinet space planning. |
| Overall height | 260 ± 5mm reference | Confirm top terminal clearance before installation. |
| Top terminal spacing | 185mm reference | Used for primary terminal clearance and conductor arrangement. |
| Weight | Approx. 27kg reference | Actual value depends on final ratio and winding configuration. |
Dimension data is for preliminary layout only. Final dimensions shall be checked against the approved outline drawing or PDF file.
Safety Notes
- Confirm model, voltage ratio, insulation level, accuracy class and output before production.
- Select JDZ8 or JDZX8 according to whether residual-voltage output is required.
- PT secondary circuits must not be short-circuited during operation.
- Use suitable fuses or MCBs for secondary-circuit protection.
- Confirm grounding, terminal marking and wiring diagram before energizing.
- De-energize the primary circuit before inspection or maintenance.