Epoxy Resin Glass Fiber DC Bushing Curing and Charge Release
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Solution Overview
Problem
Traditional DC bushings face issues such as oil leakage, moisture absorption, and space charge accumulation due to design complexities in epoxy resin impregnated glass fiber processes, affecting insulation and mechanical strength.
Innovation Solution
A method involving selecting bushing design parameters for capacitive and resistive screens, winding at controlled temperatures (90° C. to 120° C.), and precise machining to ensure initial curing and field strength distribution, along with a collector ring for charge release, to enhance the epoxy resin impregnated glass fiber DC bushing's reliability and safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional oil-impregnated paper or glue-impregnated paper production process is used, then the bushing can be manufactured with simpler process, but the bushing has risk of oil leakage, moisture absorption, and combustion/explosion hazards
Solution Approach 1:
The patent changes the fundamental material parameters from traditional oil-impregnated paper or glue-impregnated paper to epoxy resin impregnated glass fiber. This parameter change eliminates the risks of oil leakage, moisture absorption, and combustion/explosion while providing a pure solid structure with excellent mechanical strength and anti-seismic performance. The manufacturing process complexity increases but is managed through standardized procedures for winding, curing, and assembly.
2Productivity
If winding temperature is increased to accelerate initial curing process, then the core can be cured faster, but the curing process becomes harder to control and may affect field strength distribution
Solution Approach 1:
The patent optimizes the winding temperature parameter to a specific range (90°C to 120°C) that balances curing speed and controllability. This temperature parameter change accelerates the initial curing process during winding while maintaining sufficient control over the curing process. The temperature is then further controlled during oven curing at 40°C to 60°C for 24 to 48 hours to achieve complete curing with proper field strength distribution.
Solution Approach 2:
The patent applies preliminary action by conducting the initial curing process during the winding stage itself through controlled temperature heating. This preliminary curing prepares the epoxy resin impregnated glass fiber core for subsequent complete curing in the oven, ensuring proper structural formation and field strength distribution before final assembly.
3Reliability
If the length and thickness of capacitive screen are increased to improve field strength distribution, then the insulation performance is improved, but the space charge accumulation effect at medium interface increases
Solution Approach 1:
The patent optimizes the parameters of capacitive screens and resistive screens, including their length, thickness, and positioning. The capacitive screens have thickness of 2-5mm and length of 100-200mm, while resistive screens have thickness of 1-3mm. These parameter changes achieve reasonable field strength distribution that improves insulation performance while controlling space charge accumulation at medium interfaces through proper screen design and positioning.
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 method facilitates the initial curing process, achieves reasonable field strength distribution, and ensures reliable operation by grounding the collector ring to release accumulated charges, thereby improving the bushing's mechanical strength and reducing the risk of failures.
Implementation Method 1
the core begins to be initially cured during winding of the core
Implementation Method 2
a winding machine program is determined according to the bushing design parameter, and a core is wound according to the winding machine program, in which the core begins to be initially cured during winding of the core
Implementation Method 3
After the winding of the core is completed, the core is cured by an oven according to a preset oven temperature and duration
Implementation Method 4
After an inner wall of a flange is polished and cleaned and is subjected to a heating pretreatment by an oven, glue is injected
Data Source
AI summary
A method for developing an epoxy resin impregnated glass fiber Direct Current (DC) bushing, comprising: according to length parameters of each layer of capacitive screen or resistive screen designed depending on insulation requirements, selecting bushing design parameters, determining a winding machine program according to the bushing design parameters, and winding a core body according to the winding machine program, wherein during the core body winding process, the core body begins to be initially cured; after the core body is wound, curing the core body by an oven according to a preset oven temperature and duration; machining the cured core body according to a preset core body design drawing; after the inner wall of a flange is polished and cleaned and is heated and pretreated by the oven, injecting glue at the position of a glue injection hole of the flange for gluing the core body and the flange; sequentially assembling a collector ring, a hollow composite insulator, and a voltage-equalizing sealing cover on the glued core body, and mounting a conducting rod, a wiring board, and a voltage-equalizing ball; and performing various tests on the bushing according to a preset bushing standard for a DC system.