Flexible DC Transmission Capacitor

Product Introduction

The Flexible DC Transmission Capacitor is a high-performance power electronic capacitor developed for demanding DC-link applications, particularly flexible high-voltage direct current (HVDC) transmission and ultra-high-power frequency converter systems. It is designed to provide reliable energy storage, DC voltage stabilization, and electrical buffering in high-power conversion equipment.

With a rated voltage range of 1200 to 5600V DC and rated capacitance from 1500 to 18000μF, this capacitor can be configured for different high-power electrical system requirements. Its design combines a robust stainless-steel enclosure with dry-type, low-density high-performance resin potting to support reliable operation under demanding industrial conditions.

The product is suitable for applications where electrical stability, high energy-handling capability, long operating life, and mechanical reliability are important. Its fixed mounting structure with lifting lugs and bolted fixing points also facilitates installation in large-scale electrical equipment.

Key Product Features

1. Wide High-Voltage Range

The capacitor supports rated DC voltages from 1200V to 5600V, providing flexibility for different high-voltage power electronics and DC transmission system designs.

This voltage range makes the capacitor suitable for high-power converter systems where conventional low-voltage capacitors cannot meet the electrical requirements.

2. Large Capacitance for High-Power Applications

With rated capacitance available from 1500 to 18000μF, the capacitor provides substantial energy storage capacity for DC-link circuits.

The large-capacitance design can help stabilize DC voltage and support the energy buffering requirements of high-power conversion equipment.

3. Designed for HVDC and Power Conversion

The capacitor is intended for applications such as flexible HVDC transmission and ultra-high-power frequency converters, where DC-link components must withstand high electrical stress and continuous operating demands.

Its electrical characteristics make it suitable for integration into large-scale power electronic systems.

4. Long Expected Service Life

The expected lifespan reaches 100,000 hours, supporting long-term operation in industrial power equipment.

A long service-life design can reduce the frequency of capacitor replacement and help improve the maintainability of equipment using the capacitor.

5. Austenitic Stainless-Steel Enclosure

The capacitor uses a rectangular housing made of austenitic stainless steel.

The rigid metal enclosure provides mechanical protection for the internal capacitor structure and is suitable for fixed installation inside high-power electrical equipment.

6. Dry-Type Resin Potting

The product adopts a dry-type, low-density high-performance resin potting process.

The potting structure helps provide mechanical support and protection for internal components while avoiding the use of conventional liquid impregnation systems. This construction is well suited to demanding power electronic applications where structural stability and reliable insulation are important.

7. Fixed Installation Structure

The capacitor is designed for fixed mounting and incorporates lifting lugs and bolted capacitor fixing points.

This structure is suitable for larger electrical assemblies where secure mechanical installation and convenient handling are required during equipment assembly and maintenance.

Main Technical Specifications

Flexible HVDC Transmission Applications

Flexible HVDC transmission systems require power electronic equipment capable of handling high voltage and high power while maintaining stable electrical performance. Capacitors in the DC-link section play an important role in energy buffering and DC voltage stabilization.

The Flexible DC Transmission Capacitor is designed for this type of high-power environment, with a broad voltage and capacitance range that allows engineers to select a suitable specification according to system architecture.

For large transmission and conversion installations, the combination of high rated voltage, large capacitance, and long expected operating life can support continuous system operation and long-term equipment planning.

Ultra-High-Power Frequency Converter Applications

High-power frequency converters are used in industrial and energy systems that require controlled conversion of electrical power. Their DC-link circuits can experience substantial electrical and thermal demands.

A properly selected DC-link capacitor can provide energy buffering and help maintain a stable DC bus during power conversion. With rated voltages up to 5600V DC and capacitance up to 18000μF, this product is designed for high-power converter applications where higher electrical capacity is required.

The fixed stainless-steel housing and resin-potted construction further support integration into large industrial converter assemblies.

Operating Temperature Range

The specified operating temperature range is -40℃ to +70℃.

This range allows the capacitor to be considered for equipment installed in different industrial environments, provided that the complete system design remains within the applicable electrical, thermal, and mechanical operating conditions.

Temperature should be evaluated together with system load, installation location, ventilation, enclosure design, and surrounding components when selecting a capacitor for a high-power application.

Mechanical Construction

The rectangular stainless-steel enclosure provides a defined mechanical form factor for integration into power electronic equipment.

The use of austenitic stainless steel provides a rigid housing structure, while the lifting lugs support handling during installation. Bolted fixing points allow the capacitor to be securely mounted inside the target equipment.

For large-capacity capacitors, mechanical fixation is an important part of system integration. The installation structure should be matched with the equipment frame and designed to withstand the expected operating environment.

Resin Potting Design

The dry-type low-density high-performance resin potting system is an important part of the capacitor construction.

Instead of relying on a liquid impregnation arrangement, the internal structure is protected through resin potting. This approach provides mechanical stabilization and electrical insulation while forming a compact internal assembly.

For power electronic equipment, the potting material and manufacturing process can directly influence the mechanical integrity and long-term reliability of the capacitor. Therefore, consistent production processes are particularly important for high-voltage and large-capacitance products.

Selection Considerations

When selecting a DC-link capacitor for an HVDC or high-power converter project, several parameters should be evaluated together rather than considering capacitance alone.

Rated Voltage

The capacitor's rated voltage should be selected according to the maximum DC operating voltage and the required electrical margin of the system.

The available 1200–5600V DC range provides multiple options for high-voltage DC applications.

Capacitance

The required capacitance depends on the DC-link architecture, converter design, energy buffering requirements, ripple conditions, and system control characteristics.

The available 1500–18000μF range allows the capacitor to cover different high-power system configurations.

Operating Temperature

The actual equipment environment should be checked against the capacitor's -40℃ to +70℃ operating temperature specification.

Thermal conditions should be evaluated at the system level, particularly where multiple power electronic components are installed within the same enclosure.

Mechanical Installation

The dimensions, mounting points, lifting arrangements, and equipment structure should be checked before installation.

The rectangular enclosure and fixed mounting configuration make it suitable for integration into large electrical assemblies, but the final mechanical arrangement should always be confirmed against the actual equipment design.

Service Life

For large power transmission and conversion equipment, component service life is an important consideration during system planning. The product has an expected lifespan of 100,000 hours, supporting long-term applications where maintenance intervals and lifecycle costs need to be considered.

Typical Application Areas

The capacitor can be considered for a variety of high-power electrical and power electronic systems, including:

• Flexible HVDC transmission equipment

• High-power frequency converters

• Power electronic conversion systems

• High-voltage DC-link circuits

• Industrial power conversion equipment

• Large-scale energy and electrical systems

• Rail transit power electronics

• Advanced power equipment and specialized electrical systems

The final capacitor specification should be selected according to the voltage, capacitance, temperature, mechanical installation, and operating conditions of the specific equipment.

Manufacturing and Technical Background

For high-voltage and high-capacitance capacitors, product performance depends not only on component design but also on material selection, manufacturing consistency, testing, and engineering experience.

Wuxi Power Filtering Co., Ltd. has a long history in the research and production of special capacitors, high- and low-voltage power filtering equipment, reactive power compensation equipment, and power electronic capacitors.

The company was officially established following a shareholding reform in 1994 and has developed technical capabilities covering power electronic capacitors, pulse capacitors, self-healing high-voltage power capacitors, power filtering devices, and shunt capacitor compensation installations.

Its production base has a built-up area of approximately 20,000 square meters, with a registered capital of RMB 20 million. The company also maintains technical cooperation with research institutions and universities including the China Electric Power Research Institute, Southern Power Grid Electric Power Research Institute, Tsinghua University, Huazhong University of Science and Technology, and North China Electric Power University.

Its products and electrical equipment solutions have been applied in industrial and mining enterprises, power systems, rail transit, aerospace, and defense-related applications.

Quality and Engineering Focus

The company's development approach emphasizes product quality, technical development, and service. It operates as a National High-Tech Enterprise and a Wuxi City Specialized, Sophisticated, Innovative Enterprise, with a provincial-level Engineering Technology Research Center and a municipal-level Enterprise Technology Center.

This technical background supports the development of capacitors and related equipment for demanding electrical applications, including green energy, smart grids, energy conservation, environmental protection, and large-scale energy storage.

Why Consider This DC Link Capacitor?

For high-power DC transmission and conversion equipment, the capacitor is a key part of the electrical architecture rather than a simple energy storage component.

The Flexible DC Transmission Capacitor combines:

• 1200–5600V DC rated voltage

• 1500–18000μF rated capacitance

• 100,000-hour expected lifespan

• -40℃ to +70℃ operating temperature

• Austenitic stainless-steel rectangular housing

• Fixed mounting with lifting lugs and bolted fixing

• Dry-type high-performance resin potting

• Suitability for flexible HVDC and ultra-high-power frequency conversion

These specifications provide a practical starting point for engineers and equipment manufacturers evaluating DC-link capacitor solutions for high-power electrical systems.

Ordering and Technical Selection

Before placing an order, customers should provide the intended application, required DC voltage, capacitance, operating temperature, installation conditions, and equipment configuration where available.

Technical confirmation is recommended to ensure that the selected capacitor specification matches the electrical and mechanical requirements of the complete system.

For high-voltage transmission, converter, and specialized power equipment projects, specification matching should be completed before production to support reliable integration.

Product Summary

The Flexible DC Transmission Capacitor is a high-voltage, large-capacitance DC-link capacitor designed for flexible HVDC transmission and ultra-high-power frequency converter applications. With 1200–5600V DC voltage, 1500–18000μF capacitance, 100,000-hour expected lifespan, stainless-steel housing, and dry-type resin potting, it provides a robust option for demanding power electronic systems.

For customized technical requirements and capacitor selection support, customers can contact Wuxi Power Filtering Co., Ltd. to discuss the required electrical and mechanical specifications.