One-Piece Plastic Corona Shield for Composite Insulators
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Solution Overview
Problem
High-voltage composite insulators face a challenge in extending service life due to corona discharges, which can erode the insulating jacket, especially at end fittings, and existing field-shaping measures are costly and often insufficient.
Innovation Solution
A composite insulator design featuring a one-piece plastic corona shield with a hollow cavity that can be filled with sealing compound, providing enhanced protection and sealing at the transition from the rod to the end fitting, and featuring sealing collars and filling channels for effective sealing and erosion protection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional field-shaping measures (metal or semi-conductive corona rings) are used, then corona discharge is reduced, but production costs increase significantly
Solution Approach 1:
The patent replaces expensive metal or semi-conductive corona rings with a corona shield made of inexpensive insulating plastic material. This plastic corona shield achieves adequate corona protection without the high material and manufacturing costs of metallic solutions, effectively applying the principle of using cheaper materials to solve the same technical problem.
Solution Approach 2:
The invention integrates the corona shield as a molded-in part of the composite insulator assembly, combining the insulating plastic material with the structural components. This composite approach allows the corona shield to be produced as a single integrated piece rather than a separate metal component, reducing manufacturing complexity and cost while maintaining protective function.
2Duration of action of stationary object
If insulating material with greater wall thickness is used to protect against corona erosion, then service life is extended, but manufacturing complexity increases
Solution Approach 1:
The patent divides the insulator structure into functional segments: the insulating jacket for electrical insulation, and the corona shield as a separate protective component with integrated sealing collars and filling channels. This segmentation allows the corona shield to provide enhanced erosion protection through its design rather than requiring increased wall thickness throughout the entire insulator, thus avoiding unnecessary manufacturing complexity.
Solution Approach 2:
The corona shield is designed to fit over the insulating jacket in a nested configuration, with the sealing collars creating tight seals against the jacket surface. This nested design provides enhanced protection at the critical transition area without requiring the entire insulator structure to be more complex or thicker-walled.
3Reliability
If a sealed cavity structure is added to the corona shield, then sealing against water ingress is improved, but manufacturing complexity increases
Solution Approach 1:
The patent merges multiple functions into the single corona shield component: corona discharge protection, water sealing, and structural support. The sealing collars and filling channels are integrated directly into the corona shield's molded structure, eliminating the need for separate sealing components or complex assembly steps. This functional integration improves sealing performance without proportionally increasing manufacturing complexity.
Solution Approach 2:
The corona shield serves multiple purposes simultaneously: it acts as a corona discharge shield, a sealing barrier against water ingress through its collars, and a structural element that protects the transition area. The filling channels provide both manufacturing access for sealant injection and serve as part of the sealed cavity structure. This multi-functionality reduces the need for additional separate components.
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 solution effectively extends the service life of the insulator by reducing corona discharge erosion and providing a cost-effective production method, ensuring reliable sealing and protection against water ingress.
Implementation Method 1
A cavity formed by the metal half-shells is then filled with a sealing compound
Data Source
Figure 1
Figure 2~3
Figure 4
AI summary
A plastic single-piece corona shield (2) is suitable for being fitted co-axially on a composite insulator on a crossover from a rod (3) to fittings (8a,8b) at the end. The corona shield forms a cavity (16a,16b) opened inwards that can be filled with a sealing compound (22) via a filling channel and has closing sleeves (17,18) in an axial direction on both sides for sealing the cavity. An independent claim is also included for a composite insulator.