35/0.4kV 1000kVA Three-Phase Oil Immersed MV&HV Transformers
1. Product Description
The 35/0.4kV 1000kVA Three-Phase Oil Immersed MV&HV Transformer is a mainstream medium and high voltage distribution transformer widely used in industrial power grids, municipal power distribution and rural grid upgrading projects. Designed with a standard rated capacity of 1000kVA, this heavy-duty oil-filled power transformer features a precise voltage transformation ratio of 35kV medium-high voltage input to 0.4kV low-voltage three-phase output, perfectly bridging 35kV overhead transmission lines and conventional 400V industrial and civil electrical loads. Classified as a core MV&HV power conversion device, it complies fully with IEC 60076 and GB1094 international electrical standards, serving as the key step-down equipment for medium voltage power distribution systems.
Manufactured with high-quality grain-oriented silicon steel core and high-purity copper windings, this energy-saving three-phase oil immersed distribution transformer effectively reduces magnetic flux leakage, no-load loss and load loss compared with traditional old-generation transformer models. Adopting mature ONAN oil natural air cooling technology and fully sealed corrugated tank structure, the equipment completely isolates internal insulating oil from external air and moisture, preventing oil aging and insulation dampness. The optimized winding structure delivers balanced three-phase voltage output, low partial discharge and strong anti-fluctuation performance, ensuring stable and reliable continuous operation under variable load and complex grid conditions.
Available in S11, S13 and S20 ultra-low loss series configurations, this 35kV medium voltage step-down transformer supports 50Hz standard power frequency operation and off-load voltage tap adjustment. Every finished unit undergoes strict factory testing including high-voltage withstand test, short-circuit impact test and temperature rise test, with stable electrical performance and low failure rate. It is a cost-effective, durable and versatile power distribution solution for modern commercial, industrial and municipal power supply projects.
2. Core Uses
The core function of this 35/0.4kV 1000kVA oil immersed MV&HV transformer is to implement safe, efficient and stable medium-to-low voltage power conversion and regional power distribution. It professionally steps down 35kV medium-high voltage grid power to standard 0.4kV three-phase industrial and civil voltage, converting high-level transmission electric energy into usable terminal power that meets national power consumption standards, solving the voltage mismatch problem between medium voltage transmission networks and low-voltage power consumption equipment.
In daily power grid operation and industrial power supply scenarios, this high-efficiency oil-filled transformer undertakes multiple core tasks including grid voltage stabilization, load balancing, power quality optimization and fault isolation. It can effectively suppress 35kV line voltage surges, instantaneous current impacts and grid fluctuation interference, maintaining constant 0.4kV output voltage and protecting terminal electrical equipment from overvoltage and undervoltage damage. The excellent short-circuit resistance and insulation performance can block fault diffusion, improve the overall safety of medium voltage distribution systems, and reduce the risk of large-area power supply failure.
Additionally, the ultra-low loss design of this industrial distribution transformer significantly reduces long-term power transmission loss and operational energy consumption, effectively lowering daily power consumption costs for industrial enterprises and power grid operators. It also supports flexible voltage regulation to adapt to different grid voltage deviations, ensuring continuous, stable and high-quality power supply for regional centralized loads.
3. Typical Application Scenarios
3.1 Industrial Park & Factory Power Distribution
This 35/0.4kV 1000kVA three-phase oil immersed transformer is the preferred power distribution equipment for comprehensive industrial parks, small and medium-sized manufacturing factories, processing workshops and mechanical production bases. Most industrial production equipment, workshop lighting and auxiliary electrical facilities adopt 0.4kV three-phase power supply standards. The 1000kVA rated capacity fully meets the simultaneous power demand of multiple industrial loads, adapting to long-term continuous production power consumption and ensuring stable operation of industrial electrical systems.
3.2 Urban & Rural Power Grid Renovation Projects
It is widely applied in urban suburban grid upgrading, rural power grid reconstruction and township centralized power distribution projects. Many suburban and rural power transmission lines adopt 35kV medium voltage power supply mode, and this MV&HV step-down transformer can stably convert grid voltage into civilian 400V power, covering residential daily power consumption, community public facilities and township commercial power demand, effectively improving the power supply capacity and stability of regional basic power grids.
3.3 New Energy Supporting Power Supply
Suitable for supporting power distribution of distributed photovoltaic power stations, small wind power systems and rural energy storage power stations. New energy power generation has obvious intermittency and volatility, and this high-stability oil immersed transformer can stabilize fluctuating power quality, complete 35kV grid connection matching and 0.4kV terminal power conversion, realizing safe power output and local consumption of new energy power, improving new energy utilization efficiency.
3.4 Infrastructure & Public Facilities
The transformer provides reliable power support for rural water conservancy projects, road traffic monitoring stations, suburban logistics parks, scenic area supporting facilities and municipal public engineering projects. These public scenarios have stable and continuous power demand, and the equipment’s strong environmental adaptability and low-maintenance performance can adapt to long-term unattended outdoor operation, ensuring safe and stable operation of public infrastructure electrical systems.
3.5 Remote Area Power Supply Projects
It is commonly used in power supply construction of remote mountainous areas, pastoral areas and island areas with sparse population and scattered loads. The 35kV medium voltage power transmission mode is suitable for long-distance power supply in remote areas, and the 0.4kV low-voltage output perfectly matches the power demand of scattered residential households and small field operation equipment, solving the difficulty of power grid coverage in remote areas.
4. Core Product Features
4.1 Ultra-Low Energy Loss & High Power Conversion Efficiency
Adopting advanced low-loss silicon steel core and optimized electromagnetic winding design, this 35kV MV&HV transformer minimizes no-load current, magnetic flux leakage and operating loss, with energy efficiency indicators far exceeding traditional industry standards. The reasonable magnetic circuit layout maintains efficient energy conversion under no-load, light-load and full-load conditions, effectively reducing long-term grid transmission loss and user operational electricity costs, delivering outstanding energy-saving and economic benefits.
4.2 Excellent Insulation Performance & Strong Short-Circuit Resistance
The internal winding adopts high-strength insulating materials and integral fastening technology, with uniform ampere-turn distribution and strong mechanical stability. It can withstand instantaneous short-circuit impact and current surge of 35kV medium voltage grid, avoiding coil deformation and insulation damage. High-purity insulating oil provides excellent dielectric strength and heat dissipation performance, ensuring stable insulation level and safe operation under long-term high-load working conditions.
4.3 Fully Sealed Structure & Superior Environmental Adaptability
Equipped with a fully sealed corrugated oil tank, the equipment isolates internal insulating oil and windings from external air, dust and moisture, preventing oil oxidation deterioration and insulation damp failure. The whole machine undergoes multi-layer anti-corrosion spraying and rust removal treatment, adapting to high temperature, severe cold, high humidity, dust and coastal salt-fog harsh environments. It supports long-term outdoor unattended operation with strong weather resistance and environmental adaptability.
4.4 Low Operating Noise & Green Environmental Protection
Through precision core stacking process and professional vibration damping structure optimization, the operating noise of the transformer is effectively controlled at a low level, fully meeting urban and rural environmental protection noise standards. The product features low partial discharge, no electromagnetic pollution and no harmful emission during operation, conforming to the construction requirements of green energy-saving power grids, and is suitable for residential adjacent and urban suburban power distribution scenarios.
4.5 Stable Voltage Regulation & Strong Load Adaptability
Configured with standard off-load tap changer, the equipment can adjust output voltage within a conventional range to compensate grid voltage deviation, ensuring balanced and stable 0.4kV three-phase output. It has strong tolerance to unbalanced load and variable load fluctuation, can adapt to frequent load changes in industrial production and civilian power consumption, and maintains stable power supply quality in complex operating environments.
4.6 Low Maintenance & High Cost Performance
The fully sealed maintenance-free design eliminates frequent oil replenishment, oil filtration and internal cleaning work, greatly reducing daily operation and maintenance labor costs and later equipment investment. The compact and reasonable structural design saves installation space, with simple on-site installation and commissioning procedures. Compared with dry-type transformers, this oil immersed MV&HV transformer has lower initial cost, longer service life and higher comprehensive cost performance for medium voltage power distribution projects.
5. Frequently Asked Questions (FAQ)
Q1: What is the safe and optimal operating load range for the 35/0.4kV 1000kVA three-phase oil immersed transformer?
A: For long-term safe and stable operation, the optimal continuous operating load of this 1000kVA medium voltage distribution transformer is controlled at 70% to 85% of the rated capacity, which balances operating efficiency and equipment service life. It supports 110% short-term overload operation within 2 hours to cope with instantaneous peak power consumption of industrial equipment and grid load surges. Continuous full-load or overload operation is not recommended, as it will cause sustained overheating, accelerate insulation aging, increase operating loss and raise equipment failure risks.
Q2: What are the key advantages of 35/0.4kV oil immersed MV&HV transformers compared with conventional 10kV distribution transformers?
A: Different from conventional 10kV low-voltage distribution transformers, this 35kV grade MV&HV transformer adapts to longer-distance medium voltage power transmission, with stronger voltage withstand capability and wider power supply coverage. It is more suitable for long-distance power supply in rural areas, industrial zones and remote projects, effectively reducing line transmission loss. Meanwhile, it has stronger short-circuit resistance and environmental adaptability, lower failure rate in harsh outdoor environments, and is more suitable for large-scale regional centralized power distribution scenarios.
Q3: What routine maintenance work is required for this 35/0.4kV 1000kVA oil immersed transformer in daily operation?
A: This sealed oil immersed transformer features low daily maintenance requirements. Daily routine inspection mainly includes checking the tank body for oil leakage, observing oil level and oil color status, confirming no abnormal noise and overheating during operation, and regularly checking the firmness of wiring terminals and grounding devices. It is recommended to conduct a comprehensive electrical performance test including insulation resistance and transformation ratio every six months, and perform insulating oil filtration or replacement every 3 to 5 years according to the operating environment. Standardized daily maintenance can effectively extend the equipment service life up to 25-30 years.
