JDZ(X)10-10-3、6/10A(REL-10) Voltage Transformer
Product Overview
The JDZ(X)10-10-3、6/10A(REL-10) voltage transformer is a fully enclosed, dry-type, cast-resin voltage transformer designed for 10kV (Um=12kV) indoor AC power systems. It employs an integral epoxy resin vacuum-cast insulation structure with a built-in dedicated current-limiting resistor. The unit serves multiple functions including voltage measurement, energy metering, relay protection, and fuse replacement. It is primarily used in indoor medium-voltage switchgear (e.g., KYN28 series) for voltage monitoring, insulation supervision, and protection signal acquisition, and is widely applied in 10kV distribution systems, prefabricated substations, and ring main units.
Core Product Features
Insulation and Electrical Performance
Fully Enclosed Epoxy Resin Cast Insulation: The entire unit is formed by vacuum casting with epoxy resin, resulting in a void-free interior with excellent insulation performance. It withstands the 12kV system operating voltage and passes power-frequency and impulse withstand voltage tests. The insulation has a long service life with no leakage or oil contamination risk, making it suitable for oil-free indoor distribution applications.
Integrated Current-Limiting Protection: The built-in current-limiting resistor replaces conventional fuses to provide overcurrent protection for the voltage transformer, preventing damage from secondary circuit short circuits or overcurrent events, improving system operational reliability, and simplifying secondary circuit design within the switchgear.
Wide Voltage Ratio Compatibility: Supports multiple voltage ratios (e.g., 10/0.1kV, 10/0.1/0.1kV, etc.) with simultaneous multi-tap secondary outputs for metering, protection, and insulation supervision. Accuracy classes are customizable (0.2/0.5/1 / 3P/6P, etc.) to meet diverse application requirements.
Low Partial Discharge Design: Advanced casting process ensures partial discharge level ≤10pC, preventing insulation aging caused by long-term partial discharge activity and improving long-term operational reliability.
Structural and Installation Features
Fully Enclosed Dry-Type Construction: The integrally cast structure has no exposed core or live parts, with a protection degree of IP20, no fire hazard, compact dimensions, small footprint, and compatibility with standard switchgear installation dimensions.
Dual Model Design: JDZ10-10 is the single-winding type; JDZX10-10 is the residual-voltage winding type (for insulation supervision). Models can be selected flexibly based on system requirements to accommodate different switchgear types and protection schemes.
Clear Terminal Identification: Primary high-voltage terminals are clearly labeled; secondary terminals are protected by transparent covers for convenient wiring, preventing miswiring and short circuits, while also guarding against accidental secondary circuit short circuits. Terminal layout complies with switchgear internal wiring standards.
Flexible Installation: The bottom metal mounting base includes fixing holes to support bolted installation. Compatible with horizontal indoor switchgear mounting, it provides secure installation with excellent vibration resistance for compact panel arrangements.
Operational and Maintenance Features
Maintenance-Free Operation: The dry, oil-free construction eliminates leakage and fire hazards. The epoxy resin cast body has high mechanical strength, impact resistance, and aging resistance, enabling long-term maintenance-free operation, reducing O&M costs, and eliminating the need for periodic fuse replacement.
Wide Temperature Operation: Suitable for ambient temperatures from -30°C to +70°C. Epoxy resin performance remains stable across temperature extremes with no risk of embrittlement or deformation, accommodating diverse regional climate conditions.
High-Reliability Design: Windings are wound with enameled copper wire; the core is laminated from high-quality silicon steel sheets. The unit operates with low losses and low heat generation, withstands system switching overvoltages and lightning impulse overvoltages, and incorporates a stable current-limiting resistor to ensure reliable protection performance.
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); 100/3V (insulation supervision, JDZX type) (customizable) | |
| | Rated Output Current | 3A / 6A / 10A (with built-in current-limiting protection) | |
| | Metering Accuracy Class | 0.2 / 0.5 / 1 | |
| | Protection Accuracy Class | 3P / 6P | |
| | Power-Frequency Withstand Voltage (Primary) | 42kV / 1min, no breakdown | |
| | Impulse Withstand Voltage (Peak) | 75kV, no breakdown | |
| | Partial Discharge Level | ≤10pC | |
| | Insulation Resistance (HV to LV and Earth) | ≥1000MΩ | |
| Structural and Material Parameters | Insulation Medium | Full epoxy resin casting |
| | Protection Degree | IP20 | |
| | Mounting Method | Indoor post-type bolted mounting | |
| | Insulation Thermal Class | Class B (130°C) | |
| Environmental Parameters | Operating 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 |
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 prefabricated substations;
10kV distribution systems in distribution substations, industrial and mining enterprises, commercial buildings, and industrial parks;
Voltage monitoring, control, and protection signal acquisition in power automation systems;
10kV switchgear applications requiring simplified secondary circuits and fuse replacement, suitable for compact switchgear designs.
Functional Purpose: Converts high system voltage to a standardized low voltage (100V) in proportion 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 current-limiting resistor provides overcurrent protection; the JDZX type can also serve as a voltage signal source for insulation supervision devices to monitor system earth faults.
Operating Conditions
Normal Operating Conditions
Altitude: ≤2000m;
Ambient Temperature: -30°C to +70°C, without severe temperature fluctuations;
Relative Humidity: ≤95% (non-condensing);
Environmental Conditions: Free from corrosive gases, flammable/explosive media, severe vibration and shock, and significant dust or salt spray;
Installation Method: Indoor post-type mounting, away from direct sunlight, rain, and condensation.
Special Operating Conditions (Requiring Customization)
Altitude exceeding 2000m;
Ambient temperature outside the -30°C to +70°C range;
Severely polluted, salt spray, or chemically corrosive environments;
High-vibration or high-shock operating conditions;
Non-standard voltage ratios, accuracy classes, or mounting dimensions.
Installation and Maintenance
Installation Requirements
Pre-Installation Inspection: Inspect the voltage transformer for external damage — the cast body shall be free of cracks, voids, and breakage; terminal markings shall be clear and all accessories present. Verify that the model, specification, voltage ratio, rated current, and current-limiting protection function conform to design requirements.
Mechanical Fixing: Position the voltage transformer at the designated mounting location within the switchgear and secure it through the bottom mounting holes using bolts. Ensure the installation is firm with no looseness or misalignment, and that the mounting surface is level to avoid eccentric loading.
Primary (High-Voltage) Side Wiring: Connect the high-voltage terminals per design requirements, ensuring tight connections with good contact. Maintain adequate safety clearances between the high-voltage leads and earthed parts or other live parts to prevent flashover.
Secondary (Low-Voltage) Side Wiring: Connect the low-voltage terminals according to 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 (HV to LV and earth; LV to earth) to confirm insulation performance meets requirements. Verify secondary circuit wiring is correct with no short circuits or open circuits.
Maintenance Key Points
Periodically inspect the voltage transformer externally — the cast body shall show no cracks, damage, or discharge marks; primary terminals shall show no looseness or oxidation; secondary terminal protective covers shall be intact.
Periodically inspect primary and secondary connections for tightness, with no signs of overheating or discoloration. Verify secondary circuit earthing is reliable with no short circuit or open circuit risk.
Periodically test insulation resistance and voltage ratio to confirm metering and protection accuracy meets requirements, and verify that the current-limiting protection function is operating correctly.
Clean dust and contamination from the transformer surface; prevent oil or corrosive substances from adhering; keep the equipment dry and clean.
In the event of cracks, discharge, overheating, voltage ratio deviation, or protection function failure, de-energize immediately for inspection and replace the equipment if necessary. Do not operate a faulty unit.
Precautions
Secondary windings must never be short-circuited. Should a secondary circuit short circuit occur during operation, the current-limiting resistor will act 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 mechanical impacts or shocks to the cast body during installation to prevent epoxy resin cracking or insulation damage that would compromise dielectric performance.
Primary side wiring must use dedicated insulated leads with adequate safety clearances maintained from earthed parts and other live parts to prevent phase-to-phase or phase-to-earth flashover.
Equipment earthing must be reliable — the base earthing terminal must be securely bonded to the switchgear earthing busbar to ensure proper equipment earthing.
During storage, place the unit in a dry, well-ventilated, cool environment away from direct sunlight, high temperatures, humidity, and compressive loads 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.
Standard Supply Configuration
| No. | Item | Purpose |
| 1 | JDZ(X)10-10-3、6/10A(REL-10) Voltage Transformer Body | Core unit for voltage transformation, isolation, 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 low-voltage wiring terminals against miswiring and short circuits |
| 4 | Product Manual | Installation, operation, and maintenance guide including current-limiting protection description |
| 5 | Product Certificate of Conformance and Factory Test Report | Product quality and performance documentation including voltage ratio, error, and current-limiting protection test data |
Applicable Standards and Certifications
This product complies with 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, and has passed type tests. Performance meets the operational requirements of 10kV indoor power systems.
Appendix: Product Outline Drawing
