Product Overview
The 35kV oil-immersed distribution transformer is a core indoor/outdoor high-voltage power distribution device. It is suitable for three-phase AC 50Hz, 35kV power transmission and distribution systems. Widely used in urban backbone power grids, large industrial and mining enterprises, industrial parks, new energy bases, long-distance transmission support, and infrastructure power supply for railways and subways. It undertakes functions including voltage transformation, power distribution, voltage stabilization, and power transmission. It is key equipment for efficient power supply in 35kV distribution networks, suitable for large-scale power application scenarios and backbone grid expansion needs. It bears the responsibility of stepping down voltage from 110kV and above main grids and provides reliable power to end-users, balancing stability and efficiency, meeting the needs of new urbanization and the "Dual Carbon" goals.
The product adopts a fully sealed structure (non-sealed optional). The core uses high-quality, high-permeability cold-rolled grain-oriented silicon steel sheets, featuring a multi-step staggered lap joint design and uniform clamping. The windings use high-strength oxygen-free enameled copper wire (aluminum wire optional). Equipped with an efficient heat dissipation system and PCB-free environmentally friendly insulating oil, it features low loss, low noise, strong overload capacity, excellent insulation, stable operation, and long service life. It complies with national standards such as GB 1094, GB 20052, GB/T 6451-2023, and has passed CCC and ISO certifications. The quality is reliable, suitable for fields such as industry, power, and new energy with extremely high requirements for power supply reliability, meeting the needs of green grid construction and high-voltage distribution upgrades. The technology is mature with outstanding cost-performance, suitable for unattended substations and new energy collection stations.
Operating Environment
1. Ambient temperature: -30℃～+40℃, 24h average ≤ +35℃; anti-freezing design and wide-temperature-range insulating oil customizable for low temperatures to ensure oil fluidity and equipment startup, suitable for high-voltage distribution scenarios in severely cold regions and extreme temperatures like the Northwest Gobi desert.
2. Altitude: ≤1000m; customizable for high-altitude adaptation up to 4000m under special conditions, with optimized insulation structure for high-altitude environments, meeting the insulation requirements of GB 1094.3, avoiding the impact of high altitude on insulation performance, ensuring stable equipment operation.
3. Relative humidity: Daily average ≤ 95%, monthly average ≤ 90%; anti-condensation devices can be provided for humid environments to ensure insulation stability and avoid insulation aging, suitable for use in humid and polluted areas, as well as high-humidity industrial scenarios like metallurgy and petrochemicals.
4. Installation site: No violent vibration, corrosive gases, flammable or explosive dust, or conductive dust; keep away from strong electromagnetic interference, suitable for C3-C5 corrosive environments (upgradable to C5-M salt spray level), meeting the stringent requirements of industrial plants, outdoor high-voltage substations, and coastal wind power booster stations.
5. Outdoor units withstand rain, snow, sand, dust, and salt spray erosion, equipped with rain, dust, and corrosion protection enclosures and double-layer anti-corrosion coatings, with seals made of fluoroelastomer; indoor units require good ventilation and no standing water to avoid overheating, suitable for fixed laboratory and centralized switchgear room installation scenarios.
6. Installation inclination: ≤3° relative to the vertical plane. The core and windings are firmly positioned within the tank, ensuring equipment stability and even oil distribution, guaranteeing heat dissipation and insulation performance, suitable for complex installation scenarios, avoiding displacement during transport and operation.
Technical Parameters
Item | Unit | Parameters |
|---|---|---|
Rated Voltage | kV | 35±5%/0.4 (±2×2.5% customizable, supports on-load/off-load tap changing) |
Rated Frequency | Hz | 50 |
Rated Capacity | kVA | 315, 400, 500～20000 (full series, larger capacities customizable, suitable for SZ18, S13, S22 series) |
Number of Phases | --- | Three-phase |
Connection Symbol | --- | Dyn11 (common), Yyn0 (customizable) |
Cooling Method | --- | ONAN (Oil Natural Air Natural), ONAF (Oil Natural Air Forced), OFAF (Forced Oil Forced Air - customizable, forced air cooling allows capacity increase) |
Insulation Level | kV | Power frequency withstand voltage 100kV/1min; induced withstand voltage 195kV (10s), complies with GB 1094.3, HV side insulation level 95kV, LV side 4kV |
Impedance Voltage | % | 6.0%, 8.0%, 10.0%, 12.0% (matched according to capacity, customizable) |
Noise Level | dB | ≤70～85 (low-noise type customizable to ≤62dB, with optimized core structure for noise reduction) |
Protection Grade | --- | Indoor IP20; Outdoor IP33, IP54, IP65 (WF2 corrosion protection grade customizable, suitable for salt spray and high-corrosion environments) |
Insulating Oil | --- | 25# environmentally friendly transformer oil (45# low-temperature type, anti-aging type, wide-temperature-range silicone oil customizable, PCB-free, complies with relevant environmental standards) |
Product Features
1. High Efficiency, Low Loss, Outstanding Energy Savings: Uses high-permeability grain-oriented silicon steel sheets and multi-step staggered lap joint design. Optimized winding arrangement using oxygen-free copper conductors (or paper-insulated wire, self-bonding transposed conductor). Low loss and low noise, meeting national Tier 1/Tier 2 energy efficiency standards, compatible with S13/S22 series designs, suitable for long-term continuous industrial operation, contributing to energy saving and emission reduction, and lowering operating costs for grids and users.
2. Excellent Insulation, Safe and Reliable: Optimized multi-layer insulation structure for 35kV high voltage, combined with PCB-free environmentally friendly insulating oil and vacuum oil filling process, providing high insulation strength, strong short-circuit withstand capability, low partial discharge, and good thermal stability. Passes GB 1094.3 insulation tests, eliminating risks of electric leakage and oil leakage, complying with high-voltage equipment safety regulations, ensuring personnel and equipment safety, with a long service life.
3. Efficient Heat Dissipation, Strong Overload Capacity: Uses corrugated tanks or high-efficiency radiators. Forced oil forced air cooling mode is customizable. High heat dissipation efficiency and low temperature rise. Allows stable long-term operation at rated load with strong short-term overload capacity (operates continuously for 4 hours at 1.2 times rated capacity), suitable for load fluctuations in 35kV distribution networks, meeting the needs of large-scale power application scenarios and long-distance transmission support.
4. Robust Structure, Comprehensive Protection: Tank made of high-quality cold-rolled steel plate, surface treated by degreasing, rust removal, and sandblasting before painting. Good sealing and vibration resistance. The core and windings are firmly positioned within the tank, preventing displacement during transport and operation. Outdoor units have rain, dust, and corrosion protection performance, suitable for salt spray and industrial corrosive environments. Indoor units are compact and aesthetically pleasing with a small footprint, suitable for various complex high-voltage scenarios, easy to transport and install.
5. Maintenance-Free, Long Service Life: Fully sealed structure reduces insulating oil oxidation, resulting in low maintenance frequency. Service life ≥ 25 years under normal maintenance conditions. Environmentally friendly insulating oil reduces environmental impact and complies with GB 50148 acceptance standards. Modular design facilitates quick replacement of faulty components, lowering replacement and operational costs.
6.Easy Installation, Wide Versatility: Supports indoor/outdoor, floor/pole mounting. Can be directly connected to 35kV distribution networks with strong compatibility, suitable for urban backbone grids, industrial plants, new energy bases, railways, subways, and other scenarios. Convenient installation and commissioning, allowing rapid deployment, suitable for unattended scenarios
Our Advantages
1. Strong Customization Capability: Capacity, voltage, tap-changing method, protection grade, etc., can be customized according to needs, suitable for special conditions such as high altitude, low temperature, high corrosion, as well as new energy, industrial, backbone grid renovation, and infrastructure construction scenarios, meeting large-scale power consumption and long-distance transmission needs. On-load tap changers, dynamic reactive power compensation modules, etc., can be customized.
2. Standardized Production & Strict Quality Control: Standardized production with quality control throughout the entire process and multiple inspections, including insulation performance, salt spray corrosion, oil quality tests, and short-circuit impedance tests, complying with GB/T 6451-2023. Ensures consistent product performance. A complete factory test report is provided for each unit, meeting project acceptance requirements.
3. Complete Qualifications: Possesses CCC, ISO certifications, and type test reports, meeting standards such as GB 1094.3, and satisfying grid connection and large-scale project acceptance requirements without needing to prepare additional qualification materials, facilitating rapid project implementation.
4. Stable Delivery & Comprehensive Support: Stable delivery times, supporting expedited orders. Provides professional transportation, on-site installation guidance, and commissioning services, ensuring power supply continuity for 35kV distribution networks, meeting the schedule requirements of large-scale projects and reducing the risk of project delays.
5. Complete After-Sales Service: Provides full lifecycle support including technical training, regular inspections, emergency fault handling, oil testing and replacement. Localized teams improve response efficiency, shifting maintenance logic from "periodic maintenance" to "condition-based maintenance", ensuring stable equipment operation throughout its life.
Ordering Guide
Please provide the following information when ordering to ensure accurate product matching:
1. Specify the required rated capacity, input voltage (35kV)/output voltage, frequency, connection symbol, and tap-changing method (on-load/off-load) to define core power requirements, suitable for large loads and long-distance transmission support.
2. Describe the operating environment (indoor/outdoor, altitude, temperature, humidity, etc.) and any special requirements such as corrosion protection, anti-freezing, or salt spray protection, suitable for different corrosion levels and extreme environments like high altitude, severe cold, and coastal areas.
3. Determine the cooling method, insulating oil type, impedance voltage, and energy efficiency level to match actual operating conditions. Tier 1/Tier 2 energy efficiency and forced oil forced air cooling mode can be selected as needed. Specify whether capacity increase operation is required.
4. Provide installation method, cable entry/exit method, and switchgear room layout requirements to optimize the installation plan, suitable for grid renovation, large-scale new construction projects, and infrastructure construction scenarios.
5. Specify any special functional requirements such as tap-changers, temperature measurement devices, smart monitoring, dynamic reactive power compensation, etc., to meet individual usage needs and smart grid construction requirements for unattended scenarios.
