Capacitive Graded Bushing Using Ester Liquid Insulation
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Solution Overview
Problem
High voltage bushings using common oil impregnated paper technology are limited by application temperature and pose environmental pollution risks due to mineral oil leakage, restricting their use in high environmental requirement areas, and existing solid dielectric technologies are costly and resource-intensive.
Innovation Solution
A capacitive graded high voltage bushing using an ester liquid as an impregnation agent within its core, combined with a plastic mixed dielectric or paper dielectric, which eliminates liquid leakage and offers improved temperature tolerance and environmental safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If mineral oil impregnated paper technology is used for high voltage bushings, then the bushing can be manufactured with conventional materials and processes, but the bushing is limited in application temperature and poses environmental pollution risks due to oil leakage
Solution Approach 1:
The patent changes the chemical composition parameter of the insulating liquid from mineral oil to ester-based liquid. This substitution maintains the liquid's insulating and impregnating functions while eliminating the harmful combustion properties and environmental pollution risks of mineral oil, allowing the bushing to operate safely at higher temperatures without fire hazards
Solution Approach 2:
The patent uses ester-based insulating liquid that can be readily replaced or replenished if needed, rather than relying on permanent mineral oil impregnation. This approach allows for easier maintenance and environmental safety, as ester liquids are biodegradable and less harmful to the environment
2Object-affected harmful factors
If solid dielectric technologies (RIP or RIS) are used for high voltage bushings, then the bushing can be used for higher temperatures and is free of liquid leakage, but the production is extensive and raw materials are expensive
Solution Approach 1:
The patent creates a composite insulation system combining paper or synthetic fabric (solid dielectric) impregnated with ester-based liquid. This composite structure provides both the leakage prevention of solid materials and the temperature resistance of liquid-filled designs, while avoiding the high costs associated with fully solid dielectric technologies like RIS
Solution Approach 2:
The ester-based insulating liquid serves as an intermediary between the solid dielectric material and the electrical stress. It provides both mechanical impregnation for leakage prevention and electrical insulation, while allowing the bushing to operate at higher temperatures than mineral oil would permit
3Temperature
If mineral oil is used as insulating liquid, then the bushing can operate within standard temperature ranges, but the oil presents high risk of inflammability and environmental pollution
Solution Approach 1:
The patent fundamentally changes the chemical composition parameter of the insulating liquid from hydrocarbon-based mineral oil to ester-based liquid. This substitution raises the flash point and eliminates combustibility while maintaining dielectric strength, allowing the bushing to operate at elevated temperatures without fire hazards
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 ester impregnated bushing provides cost-efficient production, increased temperature tolerance, and environmental safety, enabling applications in high environmental requirement areas without the need for extensive production adaptations or expensive raw materials.
Implementation Method 1
concentric conductive layers 121 (e.g. aluminum foils) which are isolated against another and serve as a built-in capacitor for equalizing and controlling the electrical stress on the insulation and maximizing the electrical field uniformity
Implementation Method 2
the insulating liquid is an ester liquid that preferentially fills a space between the capacitive graded core 16 and a wall of the insulator chamber 111
Data Source
Figure 1
AI summary
The present invention concerns a capacitive graded bushing (1) for high electric voltage comprising: - an insulator (11) comprising an insulator chamber (111) for receiving an electrical conductor (13) and insulating matter (12); - the electrical conductor (13) located within the bushing (1) and extending through the insulator chamber (111); - the insulating matter (12) surrounding the electrical conductor (13) and comprising several concentric (cylindrical) conductive layers (121) surrounding the electrical conductor (13) for forming a uniform core insulation called hereafter capacitive graded core (16); characterized in that a dielectric insulation material (12) impregnated with an ester liquid is placed between two successive conductive layers (121).