35kV High Voltage Dry Type Transformer
The 35kV High Voltage Dry Type Transformer is a robust, three-phase cast-resin (epoxy-encapsulated) power transformer engineered for safe, reliable high-voltage to medium-voltage or medium-voltage to low-voltage transformation in demanding indoor and protected outdoor substation applications. With full high-conductivity copper windings and advanced vacuum-cast resin insulation, it eliminates oil fire risks, environmental hazards, and routine maintenance while providing superior dielectric strength, thermal endurance, excellent resistance to moisture/dust/pollution, and very low noise levels in fire-regulated. Fully compliant with IEC 60076-11, IEC 60076-1/2/3/5/20, EN 50588-1 (eco-design), IEEE C57.12.01, IEEE C57.12.91, UL 1561 (optional), and aligned with DOE efficiency guidelines (exceeding 2016 levels and prepared for 2029 loss-reduction amendments), this series achieves excellent energy efficiency (typically 99.25–99.55% at full load), ultra-low no-load and load losses, strong overload capability (up to 150% short-term), low sound levels (<65 dB standard; <60 dB low-noise execution), and a design life exceeding 40 years with virtually zero maintenance.
- Primary Voltage Ratings 35 kV (35000 V) delta or grounded wye
- Secondary Voltage Ratings 10.5 kV, 11 kV, 6.6 kV, 0.4 kV or custom
- H.V. Tap Range ± 2×2.5% HV taps or others
- Type Dry Type Transformer
- BIL 30/95kV
- Standards IEEE, ANSI, NEMA,IEC,GB
- Application office buildings, transportation facilities
- Power Rating 50-7500kVA
- Certificate IEC 60076-11, IEC 60076-1, IEC 60076-3, UL 1561
- Cooling Method OA/OF
- Opeartion Step Down & Step Up
Technical Specifications
Customization Optional
Packing and Shipping
Manufacturer Test
Routine Testing
Application
Technical Specifications
35kV High Voltage Dry Type Transformer
Technical Specifications
Accessories
| Rated Power | 50-7500kVA | |
| Rating Primary Voltage | 35kV | |
| Secondary Voltage | 480/277V 400/230V 380/220V Customized |
|
| Frequency | 50/60Hz | |
| Vector Group | Dyn11,Yyn0,Dyn5 | |
| Winding Material | Aluminum/Copper | |
| Efficiency | As IEEE,Doe 2016,CAS Std or Customized | |
| Impedance Voltage | Nominal 2% or Customized 1.1-5.75% | |
| Altitude | ≤1,000m or Customized | |
| Enclosure material | 304 Stainless Steel | |
|
Sound level |
<65 dB standard (low-noise fans & core clamping optional for <60 dB) |
|
|
Cooling |
Natural air (AN); forced air (AF) optional for overload |
|
| HV Bushing |
| LV Bushing |
| Tap changer connector |
| Lifting hook for complete transformer |
| Name plate |
Customization Optional
35kV High Voltage Dry Type Transformer
The 35kV Cast Resin Dry Type Transformer offers extensive customization to precisely meet voltage, capacity, environmental, and performance demands in medium- to high-voltage indoor systems. Primary voltage is standard at 35kV (with 33kV, 34.5kV, 36kV, or 38.5kV variants), while secondary voltages include 0.4kV, 6.6kV, 10kV, 11kV, or custom medium/low-voltage outputs for direct load or substation use. Capacities range from 500kVA to 5000kVA+ (up to 25MVA possible), with copper windings standard for superior conductivity and thermal endurance or aluminum for weight/cost optimization. Tap changers include off-circuit ±2×2.5% to ±10% or on-load (OLTC) with multiple steps for automatic regulation. Insulation class upgrades to Class H (180°C) and low-temperature-rise designs (80K/100K) support high ambients or overloads. Cooling enhancements feature forced air (AF/ANAF) fans, ducted systems, or hybrid cooling for 40–50% capacity boost, with enclosure protection from IP00 open to IP54/IP55 dust/water-resistant designs including filters or louvers.
Further options encompass vector groups (Dyn11 standard, YNd1, Dyn5, or custom) for harmonic mitigation and grounding, integrated fiber-optic temperature monitoring, partial discharge sensors, Modbus/Ethernet smart interfaces for predictive maintenance, electrostatic shielding, anti-vibration isolators reducing noise below 65–70dB, and specialized resin formulations for enhanced fire behavior or chemical resistance. Seismic qualification, marine-grade coatings, high-current bushings, and oversized terminals accommodate utility or industrial demands. These factory-direct customizations ensure maximum efficiency and reliability, positioning the transformer as a leading choice for "custom 35kV cast resin dry type transformers."
Packing and Shipping
35kV High Voltage Dry Type Transformer
Packaging the large 35kV Cast Resin Dry Type Transformer is engineered for ultimate protection of resin windings, core, and accessories during heavy-lift transport. The unit is rigidly anchored to an extra-heavy reinforced wooden skid with steel cross-bracing, multiple anti-vibration isolators, and high-strength lifting trunnions. Terminals, bushings, sensors, and fragile components receive custom-molded foam cradles and rigid protective covers. The complete assembly is wrapped in thick multi-layer moisture-proof film, anti-static sheeting, and reinforced edge/corner guards. A purpose-built, ISPM 15-compliant heavy-duty wooden crate or open steel frame fully encloses the transformer, incorporating internal supports, active desiccant systems, humidity indicators, and multi-axis electronic shock & tilt recorders to document handling and preserve dry-type integrity.
Shipping is tailored for secure, global delivery of this high-voltage cast resin unit. Ocean freight in dedicated 40ft open-top, flat-rack, or break-bulk vessels with custom cradles and certified multi-point lashing provides economical transport (typically 30–75 days to international ports). Air charter services expedite critical components in 8–20 days. Overland transport utilizes specialized low-loader trailers with hydraulic suspension, police escorts, and pre-approved heavy-haul routes for domestic/regional movements.
Comprehensive export documentation—including commercial invoices, detailed dimensional/weight manifests, origin certificates, test reports, and IEC compliance—is prepared for rapid customs clearance. Sustainable logistics incorporate reusable skids, optimised loading, and carbon-offset options. Clients benefit from secure tracking portals with real-time satellite positioning, ETA forecasts, and dedicated support. Post-arrival services include optional heavy-lift crane/SPMT offloading coordination, condition assessment, insulation verification, and packaging recycling to accelerate commissioning. Multi-unit orders leverage consolidated shipments and phased scheduling. This professional logistics ensures flawless delivery, leading searches for "secure 35kV dry type transformer shipping."
Shipping is tailored for secure, global delivery of this high-voltage cast resin unit. Ocean freight in dedicated 40ft open-top, flat-rack, or break-bulk vessels with custom cradles and certified multi-point lashing provides economical transport (typically 30–75 days to international ports). Air charter services expedite critical components in 8–20 days. Overland transport utilizes specialized low-loader trailers with hydraulic suspension, police escorts, and pre-approved heavy-haul routes for domestic/regional movements.
Comprehensive export documentation—including commercial invoices, detailed dimensional/weight manifests, origin certificates, test reports, and IEC compliance—is prepared for rapid customs clearance. Sustainable logistics incorporate reusable skids, optimised loading, and carbon-offset options. Clients benefit from secure tracking portals with real-time satellite positioning, ETA forecasts, and dedicated support. Post-arrival services include optional heavy-lift crane/SPMT offloading coordination, condition assessment, insulation verification, and packaging recycling to accelerate commissioning. Multi-unit orders leverage consolidated shipments and phased scheduling. This professional logistics ensures flawless delivery, leading searches for "secure 35kV dry type transformer shipping."
32
32 years of industry experience
Manufacturer Test
35kV High Voltage Dry Type Transformer
Progress Test
Early manufacturing stages for the 35kV cast resin dry type transformer include core validation through Epstein frame, watt-loss, and flux density testing on premium grain-oriented silicon steel to guarantee ultra-low no-load losses. Copper (or aluminum) winding production employs precision automated layering with continuous inter-turn high-potential surge testing for insulation uniformity. Pre-casting conductor and spacer alignment is verified via 3D laser scanning for accurate duct placement. Vacuum pressure impregnation cycles are monitored with real-time resin flow sensors and ultrasonic void detection. Core-coil preliminary assembly includes low-voltage excitation for magnetization curve, harmonic content, and magnetic balance profiling. These systematic validations, supported by fully serialized digital traceability, establish the foundation for high-efficiency and reliable operation. Advanced progress evaluations feature resin casting with multi-zone temperature-controlled curing, post-cure hardness testing, and thermal expansion verification. Partial discharge pre-screening during stepped voltage ramps confirms levels well below acceptance thresholds.
Design Tests
All transformer will be test after finished the production, test items as below:
♦ Insulation Power Factor
♦ Winding Resistance
♦ Impulse Tests
♦ On load Loss Test
♦ No Load Loss Test
♦ Leak Test
♦ DC Insulation Resistance Test
♦ Transformer Turns Ratio/TTR (All Tap Voltages)
♦ Impedance Voltage & Load Loss (Rated Voltage)
♦ Excitation & No-Load Loss (Rated Voltage)
♦ Applied Voltage
♦ Insulation Resistance (Rated Voltage)
♦ Temperature Rise
Transformer Factory Acceptance Test
Factory Acceptance Testing commences with high-precision ratio and polarity verification across all taps using dual-reference ratiometric instrumentation, achieving accuracy within 0.15%. No-load loss, excitation current, and harmonic spectra are exhaustively measured at 90–110% rated voltage to confirm superior core efficiency and compliance with energy standards. Winding resistance is recorded at controlled temperatures and corrected for accurate load loss segregation and thermal prediction modeling. Routine dielectric tests include applied power-frequency withstand at full specified levels, insulation resistance far exceeding minimums, and dissipation factor below 0.3%. Partial discharge measurement under induced overvoltage restricts levels to stringent low pC values. These foundational electrical tests, executed under calibrated conditions with optional witness participation, provide irrefutable baseline certification per IEC 60076-11. Sophisticated FAT continuation incorporates double-frequency induced overvoltage with ultra-sensitive partial discharge, RIV, and acoustic emission monitoring, maintaining discharge well below 10pC across the entire voltage envelope.
Routine Test - Temperature Rise
Purpose of Testing
The purpose of the temperature rise test is to detect the temperature change of the equipment under working conditions by applying the rated load current or higher load current to ensure that the insulation performance of the equipment will not be degraded or damaged due to overheating during operation.
Testing Equipment
Temperature rise tester (e.g. OMRON, FLIR, Extech, etc.)
Heating source (e.g. electric heater, heater belt, or adjustable constant temperature heater, the specific power is selected according to the equipment requirements)
Temperature sensor (e.g. RTD sensor, thermocouple, to ensure accurate measurement)
Heating source (e.g. electric heater, heater belt, or adjustable constant temperature heater, the specific power is selected according to the equipment requirements)
Temperature sensor (e.g. RTD sensor, thermocouple, to ensure accurate measurement)
Pre-Test Preparation
Disconnect the device from the power supply and ensure that the device is properly grounded and discharged.
Ensure that the connection terminals and wiring are firm to avoid looseness affecting the test results.
Test under suitable environmental conditions: relative humidity below 75%, no rain (recommended temperature: 20-30°C).
Ensure that the connection terminals and wiring are firm to avoid looseness affecting the test results.
Test under suitable environmental conditions: relative humidity below 75%, no rain (recommended temperature: 20-30°C).
Test Progress
Connect the Test Instrument:
Connect the test instrument correctly to the electrical terminals and temperature measurement points of the device under test (such as windings, cores, oil temperature measurement elements, etc.).
Initial condition record:
Measure and record ambient temperature, humidity, and atmospheric pressure at the start of the test.
Make sure the device is cold at the start.
Connect the test instrument correctly to the electrical terminals and temperature measurement points of the device under test (such as windings, cores, oil temperature measurement elements, etc.).
Initial condition record:
Measure and record ambient temperature, humidity, and atmospheric pressure at the start of the test.
Make sure the device is cold at the start.
Measure and Record
Record the following parameters regularly:
Temperature of each winding (by resistance method or temperature sensor)
Core temperature
Oil temperature (for oil-immersed equipment)
Current, voltage and power at the equipment end
Duration of load
Record changes in ambient temperature.
Temperature of each winding (by resistance method or temperature sensor)
Core temperature
Oil temperature (for oil-immersed equipment)
Current, voltage and power at the equipment end
Duration of load
Record changes in ambient temperature.
Temperature Correction
Correct the measured winding temperature rise (equipment temperature - ambient temperature) to the reference ambient temperature (usually 20°C or as required by the standard).
Repeat Testing (if necessary)
If the load is unstable or the measurement is abnormal during the test, reload and repeat the test process.
Evaluation Criteria (Reference)
The maximum temperature rise of the winding should not exceed the product standard or the manufacturer's specified value (for example: Class A insulation: ≤60°C temperature rise
Class B insulation: ≤80°C temperature rise
Class F insulation: ≤100°C temperature rise)
Class B insulation: ≤80°C temperature rise
Class F insulation: ≤100°C temperature rise)
Test standard
IEEE C57.12.01 & IEEE C57.12.91 (Dry-Type)
*These comprehensive tests ensure that each transformer meets performance standards and operates
reliably under various conditions.
Application
Predominantly deployed in large-scale industrial parks, smart grid substations, and critical infrastructure projects, offering efficient, fire-safe, high-capacity power distribution for integrated heavy industrial, utility, and renewable energy operations.
Technical Advantages
● 30+ years of manufacturing experience
● ISO and UL certified production
● Customized cable and transformer solutions
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What is a Transformer?A transformer is an electrical device used to change the voltage of alternating current (AC). It works on the principle of electromagnetic induction, converting high-voltage current into low-voltage current or low-voltage current into high-voltage current. Transformers are widely used in power transmission, distribution systems, and various electronic devices.
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What are the main uses of a transformer?The main use of a transformer is voltage conversion. Transformers are used in power transmission systems to help transfer electricity from power plants to consumers. In addition, transformers are also used in electronic devices such as chargers, televisions, power adapters, etc., to adjust the voltage to meet the requirements of different devices.
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Do you have UL listed?Yes, our transformer has UL listed. We have exported to America many pad mounted transformer,substation transformer and HV.
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