Product Overview

The 400kV three-phase oil-immersed power transformer is designed for large-scale transmission networks, interconnected regional grids, major substations, power generation facilities, and renewable energy evacuation systems. As one of the widely adopted extra-high-voltage AC transmission classes in Europe and many international power systems, 400kV technology provides an effective solution for transferring large quantities of electricity over long distances while maintaining grid stability and transmission efficiency.

400kV transformers are widely relevant to transmission systems across the United Kingdom, France, Spain, Italy, Germany, Austria, Belgium, the Netherlands, Denmark, Ireland, Portugal, Poland, Romania, Czech Republic, Slovakia, Hungary, Croatia, Serbia, Albania, Finland, Sweden, Switzerland, Ukraine, Morocco, Algeria, Tunisia, Egypt, Jordan, the United Arab Emirates, South Africa, India, Australia and other countries or regions with comparable extra-high-voltage transmission requirements. Actual voltage selection is subject to the local transmission architecture and utility specifications.

The transformer is suitable for both conventional grid infrastructure and modern power systems integrating large-scale renewable generation, providing reliable voltage transformation between high-capacity generation sources and transmission networks.

• Maximum Capacity: Up to 500MVA, with higher ratings available according to project requirements
• Voltage Class: 400kV, customizable according to system voltage and insulation requirements
• Frequency: 50Hz / 60Hz
• Cooling: ONAN / ONAF / OFAF and customized cooling systems
• Tap Changer: OLTC available for grid voltage regulation
• Design Life: More than 30 years under specified operating conditions
• Delivery: Standard production period approximately 90 days; expedited delivery available for qualified urgent projects

[Get Quotes Now!]

Product Advantages

International Grid Compatibility

400kV transmission systems are used across a wide range of national and regional power networks. HENGFENGYOU Electric can engineer transformer configurations according to the specific requirements of different grid operators and project owners.

• Applicable Standards: IEC, GB, EN, GOST, IEEE/ANSI and other applicable international or regional standards
• European Grid Applications: Technical configurations can be adapted to European-style 400kV transmission systems and project-specific utility requirements
• African & Middle Eastern Projects: Suitable for large transmission corridors, cross-border interconnections and grid reinforcement projects
• Testing & Documentation: Factory inspection, routine tests, type tests and special tests can be arranged according to the approved technical specification
• Certification Support: ISO, CE, IEC, SABS, COC, CSA, UL and other applicable documentation can be provided according to destination-market requirements

Key Product Advantages

Optimized for Regional Transmission Networks

400kV transformers are particularly suitable for high-capacity regional transmission networks where stable bulk power transfer is essential. The transformer is designed to maintain reliable operation under continuous high-voltage loading and changing network conditions.

The magnetic circuit, winding arrangement and insulation system can be optimized according to system fault levels, insulation coordination, lightning exposure, switching conditions and utility protection requirements.

Ideal for Cross-Border Power Interconnection

The 400kV voltage class is widely used in regional transmission and international interconnection projects. It can serve as a critical interface between neighboring power systems, supporting the exchange of electricity between different regions.

Typical applications include cross-border transmission corridors, regional grid reinforcement, interconnection substations and large-scale power exchange projects.

Strong Renewable Energy Evacuation Capability

Large wind farms, solar PV clusters and hydropower resources are often located far from major electricity consumption centers. 400kV transmission infrastructure can provide a high-capacity pathway for transporting this electricity to load centers.

The transformer can therefore be configured for solar power plants, wind power bases, hydropower stations, hybrid renewable energy parks and renewable energy collection substations.

Designed for Diverse Climatic Conditions

400kV substations can be located in very different geographical environments, from northern European cold regions to North African deserts and humid coastal areas.

Customized solutions can be provided for:

• Low-temperature environments
• High-temperature desert regions
• Coastal and salt-fog areas
• High-humidity climates
• High-altitude locations
• Heavy-pollution industrial zones

Special insulation coordination, creepage distance, cooling, sealing and anti-corrosion solutions can be incorporated where required.

Typical 400kV Application Markets

400kV-class transmission systems are especially significant in Europe and surrounding interconnected regions. Representative markets include:

Europe

United Kingdom, France, Spain, Ireland, Belgium, the Netherlands, Germany, Denmark, Austria, Italy, Portugal, Poland, Romania, Czech Republic, Slovakia, Hungary, Croatia, Serbia, Albania, Finland, Sweden, Switzerland and Ukraine.

Many European transmission systems use 380–400kV-class networks as major transmission backbones.

North Africa & Mediterranean

Morocco, Algeria, Tunisia and Egypt are important markets for 400kV-class transmission and regional interconnection projects. Morocco and Algeria, for example, participate in 400kV-level international interconnections, while Egypt has 400kV interconnection infrastructure with Jordan.

Middle East

Relevant markets include Jordan, the United Arab Emirates, Bahrain, Iraq, Kuwait, Oman and Qatar, particularly for large-scale generation, transmission reinforcement and GCC/regional interconnection projects.

Africa

Potential applications include South Africa, Namibia, Botswana, Mozambique, Zambia, Zimbabwe, Tanzania and Ethiopia, especially for regional power pools, renewable energy evacuation and long-distance transmission development.

Asia-Pacific

400kV-class equipment may also be relevant to selected projects in India, Australia and other Asian-Pacific markets, depending on the local voltage hierarchy and project requirements.

Why Choose HENGFENGYOU Electric for Your 400kV Projects?

Transmission-Oriented Engineering

400kV transformers are often installed at strategically important transmission substations. Their design therefore needs to consider not only electrical parameters but also network stability, fault conditions, transport limitations and long-term maintenance.

HENGFENGYOU Electric develops each transformer according to the project requirements, including:

• Rated capacity
• System voltage
• Frequency
• Short-circuit level
• Transformer impedance
• Insulation level
• Vector group
• Tap range
• Cooling requirements
• Neutral grounding configuration

Robust Mechanical & Thermal Design

Large transmission transformers experience substantial electromagnetic and thermal stresses during normal operation and system faults.

The transformer can be engineered with reinforced winding structures, optimized clamping systems and enhanced thermal design to improve resistance to short-circuit forces and maintain stable temperature performance during prolonged operation.

Intelligent Monitoring Options

For important transmission substations, condition monitoring can help utilities identify potential problems before they develop into major failures.

Optional monitoring systems include:

• Winding and oil temperature monitoring
• Oil level monitoring
• Buchholz relay
• Pressure relief device
• Online DGA monitoring
• Bushing condition monitoring
• Cooling system monitoring
• Remote SCADA communication
• Transformer condition monitoring systems

Complete Factory Testing

Before shipment, the transformer undergoes comprehensive factory inspection and testing according to the approved technical specification.

Testing may include:

• Ratio and phase displacement tests
• Winding resistance measurement
• No-load loss and excitation current
• Load loss and impedance
• Dielectric tests
• Induced voltage test
• Separate-source AC withstand test
• Lightning impulse test
• Partial discharge measurement
• Temperature-rise test
• Auxiliary and protection system inspection

All required test records and technical documentation can be prepared for customer and utility review.

International Project Support

For overseas 400kV projects, HENGFENGYOU Electric can support the complete equipment delivery process, including technical clarification, drawing approval, manufacturing, FAT, packing, international transportation, installation guidance and commissioning assistance.

The service can be coordinated with EPC contractors, utility companies, engineering consultants and local installation teams to support efficient project execution.

Ordering Instructions

To prepare a detailed technical proposal for a 400kV transformer, please provide:

• Rated Parameters: Capacity, HV/LV voltage, frequency, vector group, impedance and tap range
• Grid Conditions: System voltage, fault level, insulation coordination, BIL/LI requirements and grounding method
• Environmental Conditions: Altitude, ambient temperature, humidity, pollution level, wind, seismic conditions and installation location
• Cooling Requirements: ONAN, ONAF, OFAF or other specified cooling systems
• Tap Changer Requirements: OLTC type, tap range, number of positions and control mode
• Accessories: Bushings, conservator, Buchholz relay, pressure relief device, temperature indicators, monitoring systems and control cabinet
• Special Requirements: Oil type, anti-corrosion treatment, transformer color, communication interfaces and other project-specific requirements
• Minimum Order Quantity: 1 set
• Standard Delivery: Approximately 90 days, subject to final technical approval
• Urgent Projects: Accelerated production and international logistics can be evaluated according to project schedule