JD6-35 35kV Outdoor Oil-Immersed Voltage Transformer

Product Overview

The JD6-35 voltage transformer is an outdoor oil-immersed single-phase measurement device for 35kV high-voltage systems, delivering reliable voltage transformation with 35000/100V ratio. This oil-filled design provides superior thermal dissipation for continuous high-load operation, making it ideal for outdoor substations and transmission networks requiring high thermal capacity.

Engineered with 40.5/95/200kV insulation level and multiple accuracy classes (0.2, 0.5, 1.0), the JD6-35 accommodates precision metering to protection requirements. The fully enclosed oil box construction prevents oil aging and extends service life, while anti-pollution grades W1 (Grade II) and W2 (Grade III) ensure reliable performance in moderately to heavily polluted environments. Thermal limit output of 1000VA ensures stable operation under heavy burden conditions.

Product Display

JD6-35 voltage transformer details

Application Position

JD6-35 voltage transformer application
JD6-35 voltage transformer installation

The JD6-35 is installed in outdoor substations, high-voltage switching stations, and transmission networks where reliable voltage measurement is required with superior thermal performance. The oil-immersed insulation system provides exceptional thermal dissipation, allowing continuous operation at higher burden levels without exceeding temperature limits. The fully enclosed oil box construction prevents oil aging and extends service life, reducing maintenance requirements. Typical installation includes concrete foundation mounting with proper grounding and minimum 600mm clearance for maintenance access and oil sampling.

Main Applications

35kV outdoor substations requiring high thermal capacity
High-voltage transmission line voltage monitoring
Industrial power distribution systems with continuous heavy loads
Renewable energy substations (wind farms, solar plants)
Rural electrification projects with outdoor distribution
Utility networks requiring standard voltage measurement
Applications with moderately to heavily polluted environments (W1/W2 grades)
High-burden applications requiring 1000VA thermal limit output

Application Case Studies

Application Scenario 1: High-Load Outdoor Substation Voltage Measurement
Utilities deploy JD6-35 oil-immersed voltage transformers in 35kV outdoor substations where continuous high-load operation requires superior thermal performance. The oil-immersed insulation system provides exceptional thermal dissipation, allowing the transformer to operate at higher burden levels without exceeding temperature limits. The 1000VA thermal limit output ensures reliable performance even under heavy burden conditions in high ambient temperatures (+50°C). The fully enclosed oil box construction prevents oil aging, extending service life and reducing maintenance requirements compared to open-type designs.

Application Scenario 2: Rural Electrification Voltage Monitoring
Rural electrification projects require reliable voltage monitoring in outdoor distribution networks with varying environmental conditions. The JD6-35 provides accurate voltage transformation (35000/100V) for metering and protection applications in remote locations. The oil-immersed design withstands harsh outdoor conditions including temperature fluctuations, humidity, and pollution. Anti-pollution grade W2 (Grade III) ensures reliable performance in agricultural environments with dust, crop residue, and seasonal pollution. The robust construction and proven oil-immersed technology provide long service life with minimal maintenance, critical for remote installations where service access is limited.

Application Fit

Suitable For

Outdoor 35kV voltage measurement applications
High thermal capacity requirements (1000VA limit output)
Continuous heavy-load operation
Standard voltage transformation (35000/100V ratio)
Moderately to heavily polluted environments (W1/W2 grades)
Applications requiring superior thermal dissipation
High-voltage transmission and distribution networks
Industrial facilities with 35kV distribution systems

Not Recommended For

Indoor installation applications (use indoor-rated models)
Ground fault detection applications (use JDX6-35 with residual winding)
Current measurement applications (use CT instead)
High-voltage systems above 40.5kV (use higher voltage class models)
Applications requiring maintenance-free operation (use epoxy cast-resin models)
Space-constrained installations (oil-immersed transformers are larger)
Extreme cold environments below -5°C (use special low-temperature models)

Installation Conditions

Installation position: Outdoor substations, switching stations, or transmission networks
Ambient temperature: -5°C to +50°C
Altitude: ≤ 1000m (standard), higher altitude available on request
Insulation: Oil-immersed (superior thermal dissipation)
Frequency: 50Hz or 60Hz
Phase configuration: Single-phase (use three units for three-phase systems)
Anti-pollution grade: W1 (Grade II) or W2 (Grade III)
Enclosure: Fully enclosed oil box (prevents oil aging)
Maintenance: Periodic oil testing and seal inspection required

Technical Parameters

The JD6-35 series includes outdoor oil-immersed single-phase voltage transformers for 35kV systems. Operating temperature -5°C to +50°C, compliant with GB20840.3-2013 and IEC61869-3:2011 standards.

Model	Rated Voltage Ratio (V)	Accuracy Class & Rated Output (VA)	Thermal Limit Output (VA)	Insulation Level (kV)
JD6-35 (Standard)	35000/100	0.2: 75 0.5: 150 1.0: 250	1000	40.5/95/200

Note 1: JD6-35 – Standard voltage transformation for metering and protection applications.

Note 2: Anti-pollution grades: W1 (Grade II) for moderate pollution, W2 (Grade III) for heavy pollution.

Note 3: Rated output and its relative accuracy class only one alternative per transformer.

Note 4: If user’s data go beyond the above-mentioned scopes, they may be subject to an agreement between manufacturer and purchaser.

Installation

Dimension Reference

JD6 35 35kV Outdoor Oil Immersed Voltage Transformer dimension1
Overall dimensions vary by configuration. Type 1 (V-shape dual-bushing): Height 1142±20mm, Width 970±15mm, Weight 143kg (oil 29kg). Type 2 (single vertical bushing): Height 1285±20mm, Width 490mm, Weight 126kg (oil 24kg). Mounting: 4×M12 mounting bolts on base plate. Clearance: Minimum 600mm around transformer for maintenance access and oil sampling. Top terminals: High-voltage bushings with M16 studs. Secondary outlet: Bottom terminal box for cable connection.

Installation Guidelines

Foundation: Install on a level concrete foundation capable of supporting 126-143kg weight. Foundation should be 150mm above ground level to prevent water accumulation and facilitate oil sampling. Use anchor bolts (M12) secured into foundation with minimum 200mm embedment depth.
Grounding: Connect the grounding terminal to the substation grounding grid using copper conductor with minimum 50mm² cross-section. Ensure grounding resistance is less than 4 ohms. Ground the transformer base and secondary winding neutral point.
Clearance: Maintain minimum 600mm clearance on all sides for maintenance access, oil sampling, and ventilation. Ensure adequate clearance from live parts according to local electrical codes (typically 400mm for 35kV).
Primary Connection: Connect primary terminals (A, N) to the 35kV power system using appropriate high-voltage conductors or busbars. Ensure proper phase sequence and torque specifications (typically 60 N·m for M16 bolts).
Secondary Connection: Connect secondary terminals to metering devices, protection relays, or monitoring equipment according to the wiring diagram. Use shielded cables for secondary circuits to minimize electromagnetic interference. Ensure proper termination and labeling.
Oil Level Check: Before energizing, check the oil level indicator (if equipped) to ensure proper oil level. The oil level should be between MIN and MAX marks. If oil level is low, contact manufacturer for oil filling procedure.
Commissioning Tests: Perform insulation resistance test (minimum 1000 MΩ at 20°C), turns ratio test, polarity test, and oil dielectric strength test (minimum 30kV/2.5mm) before energizing. Verify all connections are tight and properly torqued.

Oil-Immersed Insulation Features

Superior Thermal Dissipation: Oil-immersed insulation provides exceptional thermal dissipation, allowing the transformer to operate at higher burden levels without exceeding temperature limits. The oil circulates naturally, transferring heat from the core and windings to the outer tank walls, where it is dissipated to the ambient air.
High Thermal Capacity: The oil-immersed design provides high thermal capacity (1000VA thermal limit output), enabling continuous operation under heavy burden conditions. This is critical for applications where transformers operate near their thermal limits in high ambient temperatures.
Fully Enclosed Construction: The fully enclosed oil box prevents oil aging by minimizing exposure to air and moisture. This extends oil service life and reduces maintenance requirements compared to open-type designs. The sealed construction also prevents contamination from dust and pollutants.
Excellent Dielectric Strength: Transformer oil provides excellent dielectric strength, ensuring reliable insulation between windings and from windings to ground. The oil fills all voids and gaps in the insulation system, providing uniform electric field distribution and preventing partial discharge.
Proven Technology: Oil-immersed transformers have been used for over a century in high-voltage applications, providing a proven track record of reliability and performance. The technology is well-understood, and maintenance procedures are standardized.

Standards

GB20840.3-2013 (Instrument transformers – Part 3: Inductive voltage transformers)
IEC61869-3:2011 (Instrument transformers – Part 3: Inductive voltage transformers)
Customer-specific requirements available on request

Selection Guide

When selecting the JD6-35 voltage transformer, consider the following factors:

Accuracy Class: Choose 0.2 for revenue metering, 0.5 for monitoring applications, 1.0 for general measurement
Burden Requirements: Ensure the rated output matches the connected load (metering devices, relays) to maintain accuracy. Thermal limit output is 1000VA
Environmental Conditions: Verify ambient temperature (-5°C to +50°C), altitude (≤1000m standard), and anti-pollution grade (W1 for moderate, W2 for heavy pollution) match your installation environment
Maintenance Capability: Oil-immersed transformers require periodic oil testing and seal inspection. Ensure this aligns with your maintenance strategy and resources
Thermal Performance: If superior thermal dissipation is required for continuous heavy-load operation, oil-immersed design provides better performance than epoxy cast-resin alternatives
Ground Fault Detection: If ground fault detection is required, consider JDX6-35 model with residual voltage winding instead

Ordering Information

When ordering the JD6-35 voltage transformer, please specify:

Model: JD6-35
Rated voltage ratio: 35000/100V
Accuracy class and rated output (e.g., 0.2/75VA, 0.5/150VA, 1.0/250VA)
Anti-pollution grade: W1 (Grade II) or W2 (Grade III)
Rated frequency (50Hz or 60Hz)
Quantity required
Any special requirements or custom specifications

FAQs

JD6-35 is a standard voltage transformer with 35000/100V ratio for basic voltage measurement and protection. JDX6-35 includes a residual voltage winding with 35000/√3/100/√3/100/3V ratio, providing ground fault detection capability through the open-delta secondary winding configuration. Choose JD6-35 for standard voltage transformation, or JDX6-35 if ground fault detection is required.

Oil-immersed transformers require periodic maintenance including oil quality testing (dielectric strength, moisture content, acidity), seal inspection for leaks, bushing inspection, and temperature monitoring. Recommended maintenance intervals are annually for critical applications or every 2-3 years for standard applications. The fully enclosed design reduces maintenance frequency compared to open-type transformers.

Oil-immersed insulation provides superior thermal dissipation, allowing higher thermal capacity (1000VA limit output) and continuous operation under heavy burden conditions. The oil circulates naturally, transferring heat from core and windings to tank walls. Epoxy cast-resin transformers are maintenance-free but have lower thermal capacity and are better suited for space-constrained indoor applications.

W1 (Grade II) is suitable for moderate pollution environments such as rural areas and light industrial zones. W2 (Grade III) is recommended for heavy pollution environments such as coastal areas with salt spray, chemical plants, cement factories, and mining operations. Choose W2 if your installation site is within 10km of coastline or in areas with significant industrial pollution.

For revenue metering applications, accuracy class 0.2 is recommended to ensure precise energy measurement with 75VA rated output. Class 0.5 (150VA) is suitable for monitoring and general measurement applications. Class 1.0 (250VA) is used for general measurement where high precision is not critical.

With proper installation and regular maintenance, oil-immersed transformers have service life exceeding 30 years. Key factors affecting service life include operating temperature, load conditions, oil quality maintenance, and environmental factors. The fully enclosed design prevents oil aging, extending service life. Regular oil testing and maintenance ensure reliable operation throughout the equipment lifespan.

Standard ratio is 35000/100V. Custom ratios can be manufactured based on specific project requirements. Please contact our technical team for custom specifications and lead times. Custom ratios may affect accuracy class and rated output capabilities.

The JD6-35 complies with GB20840.3-2013 (Chinese standard) and IEC61869-3:2011 (international standard) for voltage transformers, ensuring compatibility with both domestic and international high-voltage measurement applications. The transformers are tested and certified according to these standards for accuracy, insulation, and thermal performance.