Insulated Operating Rod for Gas-Insulated Switchgear
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Solution Overview
Problem
Conventional gas-insulated switchgear using fiber-reinforced plastics (FRP) for insulated operating rods faces issues with dielectric strength degradation due to cracked gas damage and the creation of minute gaps that weaken insulation, while attempts to address these problems, such as using electric field controlling shields, hinder device downsizing and increase component complexity.
Innovation Solution
A gas-insulated switchgear design featuring a bar-shaped rotary shaft with a large-diameter, elliptically shaped part embedded in a filler-filled resin insulated operating rod, which enhances dielectric strength through improved abrasion resistance and mechanical reinforcement, and reduces residual stress, allowing for a smaller-sized device with fewer components while maintaining reliable insulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If FRP (fiber reinforced plastics) is used for the insulated operating rod, then cost is reduced and mechanical strength is improved, but dielectric strength is greatly lowered due to follow fibers and cracked gas damage
Solution Approach 1:
The patent uses a composite material structure consisting of a resin base material reinforced with fibrous materials (such as glass fibers or carbon fibers) to create the insulated operating rod. This composite structure provides both the required mechanical strength and maintains dielectric strength by carefully selecting the fiber orientation and resin composition, avoiding the follow fiber problem while retaining reinforcement benefits.
2Reliability
If an electric field controlling shield is added to cover the minute gap, then insulation reliability is improved, but device size increases and complexity increases
Solution Approach 1:
The patent removes the separate electric field controlling shield component by integrating the electric field control function directly into the insulated operating rod structure. The rod's design itself creates the necessary electric field distribution, eliminating the need for additional shield components and simplifying the overall device structure.
Solution Approach 2:
The patent combines multiple functions into the insulated operating rod: mechanical operation transmission, electrical insulation, and electric field control. By merging these functions into a single integrated component, the device achieves reliable insulation without requiring separate shields, thereby reducing component count and device complexity.
3Ease of manufacture
If conventional FRP with follow fibers is used, then manufacturing cost is reduced, but dielectric strength is greatly lowered due to aging degradation from cracked gas
Solution Approach 1:
The patent changes the material parameters by selecting specific resin types (such as epoxy resin, polyimide resin, or PTFE) and controlling the fiber content, orientation, and distribution within the composite material. These parameter adjustments ensure the material resists cracked gas degradation while maintaining manufacturability and cost-effectiveness.
Solution Approach 2:
The patent employs a carefully designed composite material system where the resin matrix protects the reinforcing fibers from cracked gas attack, preventing aging degradation. The composite structure allows cost-effective manufacturing while achieving long-term dielectric strength reliability through proper material selection and formulation.
Data Source
Figure 1~2
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AI summary
Large-diameter part 16 is formed at the axial-middle part of rotary shaft 15 that rotates driven by operating device. Insulated operating rod 14, the distal end of which makes move in the form of a segment of a circle effected by the rotation of rotary shaft 15, is formed integrally using filler-filled resin over large-diameter part 16 of rotary shaft 15 by cast so that the large-diameter part 15 is embedded into one end of insulated operating rod 14. The contact and connection between insulated operating rod 14 and moving rod 13 is given such sliding surface 21 as is formed for example in an elliptical shape so that the contact occur always at almost one-point on the axis line of the moving rod 13.