JDZ(X)10-10-3、6/10B(RZL-10) Voltage Transformer
Section I: Product Overview
The JDZ(X)10-10-3、6/10B(RZL-10) voltage transformer is a fully-enclosed, dry-type, cast-resin voltage transformer designed specifically for 10kV (Um=12kV) indoor AC power systems. As an enhanced variant of the JDZ(X)10 series, it employs an integral epoxy resin vacuum-cast insulation structure with a built-in high-performance current-limiting protection device. It is primarily used for voltage measurement, energy metering, relay protection, and insulation supervision in indoor medium-voltage switchgear (e.g., KYN28 series), and is widely applied in 10kV distribution systems, pad-mounted substations, and ring main units — suitable for distribution systems with high reliability requirements.
Section II: Core Product Features
Insulation and Electrical Performance
Fully-Enclosed Epoxy Resin Cast Insulation: The entire unit is formed by vacuum casting with epoxy resin, leaving no internal air voids. Insulation performance is excellent, capable of withstanding the 12kV system operating voltage as well as power-frequency and impulse withstand voltage tests. The insulation service life is long, with no risk of leakage or oil contamination — suitable for indoor oil-free distribution environments.
Enhanced Current-Limiting Protection: The built-in high-performance current-limiting protection device provides superior short-circuit withstand capability, effectively preventing damage to equipment caused by secondary circuit short-circuits or overcurrents. Compared to standard-type products, it offers faster protection response and higher reliability, improving overall system operational stability.
Wide Voltage Ratio Compatibility: Supports multiple voltage ratios (e.g., 10/0.1kV, 10/0.1/0.1kV, etc.), capable of simultaneously providing multiple secondary outputs for metering, protection, and insulation supervision. Accuracy classes are customizable (0.2/0.5/1 / 3P/6P, etc.) to meet multi-application requirements.
Low Partial Discharge Design: Advanced casting technology ensures partial discharge level ≤10pC, preventing insulation aging caused by long-term partial discharge and improving long-term operational reliability.
Structural and Installation Features
Fully-Enclosed Dry-Type Construction: The integral cast construction has no exposed iron core or live parts. Protection class IP20, no fire hazard, compact structure, small footprint, compatible with standard switchgear mounting dimensions.
Dual Model Design: JDZ10-10 is the single-winding type; JDZX10-10 is the type with a residual voltage winding (for insulation supervision). Selection can be made flexibly based on system requirements, compatible with different cabinet types and protection schemes.
Clear Terminal Markings: Primary high-voltage terminals are clearly labeled; secondary terminals are protected by transparent covers for convenient wiring, preventing miswiring and short-circuits while effectively guarding against accidental secondary circuit short-circuits. Terminal layout conforms to in-cabinet wiring standards.
Flexible Mounting: The bottom metal mounting base features fixing holes, supporting bolt-fixed installation. Suitable for horizontal indoor cabinet installation — sturdy, with excellent vibration resistance, facilitating compact in-cabinet arrangement.
Operational and Maintenance Features
Maintenance-Free Operation: Dry oil-free construction with no leakage or fire hazard. The epoxy resin cast body has high mechanical strength, impact resistance, and aging resistance — maintenance-free during long-term operation, reducing O&M costs, with no need for periodic fuse replacement.
Wide Temperature Operation: Operable across -30°C to +70°C ambient temperature range. Epoxy resin performance remains stable at both high and low temperatures with no risk of embrittlement or deformation, suitable for various regional climate conditions.
High-Reliability Design: Windings are wound with enameled copper wire; the iron core is laminated with high-quality silicon steel sheets, resulting in low operating losses and minimal heat generation. The unit withstands overvoltages, including system switching overvoltages and lightning impulse overvoltages. The current-limiting protection device performs stably, ensuring reliable protection functionality.
Section III: Technical Parameters (Typical Specifications)
| Parameter Category | Item | Technical Specification |
| Electrical Parameters | System Voltage | 10kV AC (Um=12kV) |
| | Rated Frequency | 50Hz | |
| | Rated Primary Voltage | 10kV | |
| | Rated Secondary Voltage | 100V (metering/protection); 100/√3 V (insulation supervision, JDZX type) (customizable) | |
| | Rated Output Current | 3A / 6A / 10A (enhanced current-limiting protection) | |
| | Metering Accuracy Class | 0.2 / 0.5 / 1 | |
| | Protection Accuracy Class | 3P / 6P | |
| | Power-Frequency Withstand Voltage (HV terminal) | 42kV / 1min, no breakdown | |
| | Impulse Withstand Voltage (peak) | 75kV, no breakdown | |
| | Partial Discharge Level | ≤10pC | |
| | Insulation Resistance (HV to LV and ground) | ≥1000MΩ | |
| Structural and Material Parameters | Insulating Medium | Full epoxy resin cast |
| | Protection Class | IP20 | |
| | Mounting Method | Indoor post-type bolt mounting | |
| | Thermal Class of Insulation | Class B (130°C) | |
| Environmental Parameters | Applicable Altitude | ≤2000m (high-altitude customization available) |
| | Operating Ambient Temperature | -30°C to +70°C | |
| | Storage Ambient Temperature | -40°C to +85°C | |
| | Relative Humidity | ≤95% (non-condensing) | |
| Applicable Standards | National Standards | GB 1207 Voltage Transformers; GB/T 20840.1 Instrument Transformers — Part 1: General Requirements; GB/T 20840.3 Instrument Transformers — Part 3: Additional Requirements for Inductive Voltage Transformers |
Section IV: Application Scope
Applicable Voltage Class: 10kV (Um=12kV) indoor AC power systems.
Typical Application Scenarios:
Voltage measurement, energy metering, and relay protection in indoor medium-voltage switchgear (KYN28 series) and pad-mounted substations;
10kV distribution systems in substations, industrial and mining enterprises, commercial buildings, and industrial parks;
Voltage monitoring, control, and protection signal acquisition in power automation systems;
Indoor 10kV switchgear applications requiring high-reliability current-limiting protection, compatible with compact switchgear designs.
Functional Purpose: Proportionally steps down high system voltage to a standard low voltage (100V) to provide voltage signals for metering instruments, protection devices, and control equipment, while achieving electrical isolation between the primary and secondary systems. The built-in enhanced current-limiting protection device provides overcurrent protection. The JDZX type can also serve as a voltage signal source for insulation supervision devices to monitor system earth faults.
Section V: Service Conditions
Normal Service Conditions
Altitude: ≤2000m;
Ambient Temperature: -30°C to +70°C, without severe temperature fluctuations;
Relative Humidity: ≤95% (non-condensing);
Environmental Conditions: No corrosive gases, no flammable or explosive media, no severe vibration or shock, no significant dust or salt mist;
Installation: Indoor post-type mounting, protected from direct sunlight, rain, and condensation.
Special Service Conditions (Customization Required)
Altitude exceeding 2000m;
Ambient temperature outside the -30°C to +70°C range;
Severely polluted, salt mist, or chemically corrosive environments;
High-vibration or high-shock operating conditions;
Non-standard voltage ratios, accuracy classes, or mounting dimension requirements.
Section VI: Installation and Maintenance
Installation Requirements
Pre-Installation Inspection: Inspect the appearance of the voltage transformer — the cast body must be free of cracks, voids, and damage; terminal markings must be clear and all accessories must be present. Verify that the model, specification, voltage ratio, rated current, and design requirements are consistent, and confirm that the enhanced current-limiting protection function is intact.
Mechanical Mounting: Position the voltage transformer at the designated location within the switchgear cabinet and secure it with bolts through the bottom mounting holes. Ensure the installation is firm with no looseness or misalignment; the mounting surface must be level to avoid eccentric loading.
Primary (HV) Side Wiring: Connect the high-voltage terminals per design requirements, ensuring tight connections with good contact. Maintain adequate safety clearance between the HV leads and grounded parts or other live parts to prevent discharge.
Secondary (LV) Side Wiring: Connect the low-voltage terminals according to their markings, with separate wiring for metering, protection, and insulation supervision circuits. Ensure correct wiring; the secondary circuit must never be short-circuited and must be reliably earthed (single-point earthing) to prevent overvoltage.
Insulation Testing: After installation, measure the insulation resistance of the voltage transformer (HV to LV and ground; LV to ground) to confirm insulation performance meets requirements. Verify secondary circuit wiring is correct with no short-circuits or open circuits.
Maintenance Guidelines
Periodically inspect the appearance of the voltage transformer — the cast body must be free of cracks, damage, and discharge marks; HV terminals must show no looseness or oxidation; secondary terminal protective covers must be intact.
Periodically inspect HV and LV connections for tightness, with no signs of overheating or discoloration; confirm LV circuit earthing is reliable with no short-circuit or open-circuit risk.
Periodically test insulation resistance and voltage ratio to ensure metering and protection accuracy meets requirements; also verify that the enhanced current-limiting protection function is operating correctly.
Clean dust and contaminants from the transformer surface; prevent oil residue or corrosive substances from adhering; keep the equipment dry and clean.
If abnormalities such as cracks, discharge, overheating, voltage ratio deviation, or protection function failure occur, de-energize immediately for inspection. Replace the equipment if necessary. Operation under fault conditions is strictly prohibited.
Section VII: Precautions
The secondary winding must never be short-circuited. If a secondary circuit short-circuit occurs during operation, the enhanced current-limiting protection device will actuate to protect the equipment; however, the fault must still be investigated and cleared promptly. During maintenance, the secondary circuit must be reliably open-circuited and earthed.
Avoid knocking or impacting the cast body of the voltage transformer during installation to prevent cracking of the epoxy resin and insulation damage, which would compromise the insulation performance of the equipment.
High-voltage side wiring must use dedicated insulated leads, maintaining adequate safety clearance from grounded parts and other live parts to prevent phase-to-phase or phase-to-earth discharge.
Equipment earthing must be reliable; the base earthing terminal must be securely connected to the cabinet earthing busbar to ensure proper equipment grounding.
During storage, keep the unit in a dry, well-ventilated, cool environment, protected from direct sunlight, high temperatures, moisture, and mechanical compression, to prevent aging or deformation of the cast body.
Installation, commissioning, and maintenance must be performed by qualified electrical personnel in strict accordance with electrical safety operating procedures.
Section VIII: Standard Supply Scope
| Item No. | Description | Purpose |
|---|---|---|
| 1 | JDZ(X)10-10-3、6/10B(RZL-10) Voltage Transformer Body | Core equipment performing voltage transformation, isolation, enhanced current-limiting protection, and signal acquisition |
| 2 | Mounting Bolts and Washers | For mechanical fixing of the voltage transformer |
| 3 | Secondary Terminal Transparent Protective Cover | Protects LV wiring terminals against miswiring and short-circuits |
| 4 | Product Manual | Installation, operation, and maintenance guide, including enhanced current-limiting protection instructions |
| 5 | Product Certificate of Conformity and Factory Test Report | Product quality and performance documentation, including voltage ratio, error, and current-limiting protection test data |
Section IX: Applicable Standards and Certifications
This product complies with the following national standards: GB 1207 Voltage Transformers, GB/T 20840.1 Instrument Transformers — Part 1: General Requirements, and GB/T 20840.3 Instrument Transformers — Part 3: Additional Requirements for Inductive Voltage Transformers. The product has passed type tests and its performance meets the operational requirements of 10kV indoor power systems.
Appendix: Product Outline Drawing