Modern power grids with renewable energy sources and dynamic loads create severe thermal stress on transformer bushings, causing critical hotspots that limit capacity and reduce lifespan. Our proven heat pipe technology eliminates these thermal bottlenecks, enabling up to 49% higher load capacity while extending equipment life and ensuring reliable operation under demanding grid conditions.
The key challenges of Modern Grids
Changing Load Patterns
Modern power grids face growing electrical demands and significant power flow fluctuations from renewable energy sources, creating continuous thermal stress. Rising peak loads from business growth and equipment outages create overload situations, while the cyclical nature of renewables generates ongoing thermal challenges for bushing insulation.
Equipment Limitations
High electrical loads accelerate the aging of components, increasing the risk of prolonged power outages and costly repairs. Bushings have become critical limiting factors for transformer overload capability, restricting grid flexibility and reliability.
Technical issues with Dry-Type
Dry-type bushings suffer from uneven temperature distribution creating dangerous hotspots near the flange area. The epoxy resin acts as a thermal barrier, restricting heat dissipation and preventing optimal conductor utilization, which ultimately determines current capacity limits.
The Solution:
Heat Pipe Technology
The heat pipe technology leverages the skin effect phenomenon where only the outer 10-12mm of a conductor carries current at 50/60Hz frequencies, allowing the inner volume to be utilized for thermal management. This innovative design replaces the traditional solid conductor with a thick-walled sealed tube filled with environmentally friendly liquid, creating an efficient heat transport system within the existing conductor space.
The heat pipe solution enables up to 49% higher load capacity within the same installation space, extending service life for bushings experiencing frequent load changes. The technology offers retrofit capability for existing transformers, reduces CO2 footprint through optimized material usage, and operates passively without external power or control systems while maintaining identical electrical performance to standard bushings.
How it works
Heat Pipe in numbers
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overall temperature rise in bushing
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UHVDC installations
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AC bushings currently in operation
Key benefits of the Heat Pipe
Environmental Benefits
Despite higher initial manufacturing costs, the heat pipe design reduces the overall CO2 footprint through optimized material usage and improved efficiency. The system operates completely passively, requiring no external power sources or control systems, making it an environmentally sustainable solution that reduces energy consumption while enhancing performance.
Operational Advantages
The heat pipe technology delivers higher overload capacity within the same installation space, providing additional safety margins for overloads or enabling higher rated currents without physical modifications. Bushings experiencing frequent load changes are treated more gently due to improved thermal management, resulting in extended service life.
Technical Reliability
The heat pipe technology maintains identical electrical performance and proven voltage control compared to standard bushings, ensuring seamless integration into existing systems. It enables resilient transformer operation with dynamic overload capabilities without requiring larger bushing sizes, providing utilities with enhanced grid flexibility and reliability under demanding operational conditions.
Operational Thermal Advantages and Performance Validation
Comprehensive testing with a 420kV 2500A bushing demonstrates the heat pipe's effectiveness: standard bushings show hotspot temperature rises of ~88K with significant temperature drops toward the free-air side, while heat pipe-equipped bushings maintain uniform 60-70K distribution throughout the active part. The heat pipe eliminates problematic temperature gradients, creating nearly uniform temperature rise across the entire bushing.
For enhanced performance, an optional heat sink can be mounted at the bushing top, extending the connection by approximately 100mm. This combination optimizes thermal management: the heat pipe improves internal energy transport while the heat sink maximizes external energy dissipation. The design maintains all standard connections, with only the internal conductor replaced by the environmentally friendly heat pipe, ensuring seamless integration and superior performance in identical physical dimensions.
Do you have any questions?
Just contact our expert!
Dr. Bernhard Heil
Manager Engineering, HSP Germany
