Bushing With Low-Viscosity Insulating Fluid
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Solution Overview
Problem
High voltage bushings face challenges in thermal performance and safety due to limited current capacity and potential for overheating, particularly in high voltage electrical facilities like transformers and switchgear.
Innovation Solution
A bushing design incorporating a low viscosity, bio-degradable insulating fluid and a condenser body with impregnated paper layers, along with hollow conductors and strategically placed holes for enhanced fluid circulation, improves thermal performance and cooling efficiency, allowing for higher current carrying capacity and reduced hotspot temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional insulating fluid with higher viscosity is used in the bushing, then the bushing provides adequate electrical insulation, but the thermal performance is limited and cooling efficiency is reduced
Solution Approach 1:
The patent changes the viscosity parameter of the insulating fluid by selecting fluids with viscosity ≤2 mm²/s at 100°C (such as ester-based fluids). This parameter change enables significantly improved convective cooling and heat dissipation while maintaining adequate electrical insulation properties, thereby resolving the contradiction between thermal performance and insulation capability.
2Power
If the bushing operates at higher current capacity, then the power transmission is improved, but the hotspot temperature increases and operational safety decreases
Solution Approach 1:
The patent changes the thermal conductivity and viscosity parameters of the insulating fluid to achieve superior heat transfer characteristics. This allows the bushing to operate at higher current capacities while maintaining hotspot temperatures within safe limits, thus improving power transmission without compromising operational safety.
Solution Approach 2:
The patent utilizes the convective flow properties of the low-viscosity insulating fluid to create an efficient hydraulic cooling system within the bushing. The fluid circulates through the condenser body and conductor, carrying heat away from hotspots and distributing it throughout the system, enabling higher current capacity while maintaining reliability.
3Productivity
If the insulating fluid has low viscosity for improved circulation, then cooling by convection is enhanced, but the electrical insulation properties may be compromised
Solution Approach 1:
The patent carefully selects insulating fluids (such as ester-based fluids) whose physical-chemical parameters simultaneously satisfy both requirements: viscosity ≤2 mm²/s at 100°C for optimal convective cooling, while maintaining dielectric strength and insulation resistance adequate for high voltage applications. This parameter optimization resolves the contradiction between cooling efficiency and insulation reliability.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The improved thermal performance enhances operational safety and life expectancy by enabling higher current handling and reducing the risk of overheating and insulation damage, while also being environmentally friendly and cost-effective.
Implementation Method 1
the low viscosity of the insulating fluid enables an improved circulation of the insulating fluid in the bushing. Thereby, the thermal performance of the bushing can be enhanced and cooling by convection can be improved
Implementation Method 2
The first and second holes enable circulation of the insulating fluid between the inside and the outside of the electrical conductor. Thereby, a cooling of the hotspot of the electrical conductor is improved
Data Source
Figure 1
Figure 2~3
Figure 4~5
AI summary
A bushing (1) comprises an insulating housing (10), an electrical conductor (2), extending through the housing (10) and an insulating fluid (13) in the housing (10), wherein the insulating fluid (13) has a viscosity at a temperature of 100 °C of equal or less than 2 mm2/s.