Compact Earthing Switch for Gas Insulated Substations
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Solution Overview
Problem
The existing earthing switches for gas insulated substations are complex and expensive to install, requiring significant design modifications and additional insulation means due to their design integration with the substation's compartment, making them costly and difficult to integrate into existing systems.
Innovation Solution
A compact electric earthing switch design featuring a metallic housing with an insulating plate, fixed and sliding earth contacts, and a compact actuating mechanism enclosed within a single housing, allowing for easy mounting on standard flanges without extensive modifications, with the actuating mechanism being driven from an external compartment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the earthing switch is integrated into the compartment enclosing the bus bars with additional insulating means, then proper electrical insulation is achieved, but the device complexity and installation cost increase significantly
Solution Approach 1:
The housing is divided into two separate compartments: an inner compartment containing gas-insulated components (line contacts and sliding earth contacts) and an outer compartment containing the actuating mechanism. This segmentation allows each compartment to be optimized independently for its specific function, reducing overall complexity while maintaining insulation reliability.
Solution Approach 2:
The actuating mechanism is extracted from the gas-insulated environment and placed in the outer compartment that is not filled with dielectric gas. This eliminates the need for complex insulating means around the actuating mechanism while preserving the insulation integrity of the electrical contacts through the insulating plate separation.
2Reliability
If the earthing switch requires integration with the compartment design, then proper alignment and insulation are ensured, but the ease of manufacture and installation deteriorate
Solution Approach 1:
The switch housing is designed as a self-contained unit that combines the inner compartment with insulating plate, line contacts, sliding earth contacts, and actuating mechanism. This merged design allows the entire switch assembly to be manufactured and tested as a complete module, then installed as a single unit onto the compartment, ensuring proper alignment without requiring complex integration work.
Solution Approach 2:
The housing design with its flange and insulating plate serves multiple functions simultaneously: it provides structural support, ensures proper alignment with the compartment, maintains electrical insulation, and houses all switch components. This multi-functionality reduces the need for additional separate components and simplifies installation.
3Reliability
If existing earthing switches use additional insulating means, then electrical insulation is maintained, but the productivity and cost-effectiveness decrease
Solution Approach 1:
By segmenting the housing into gas-insulated and non-insulated compartments, the design eliminates the need for additional insulating means around the actuating mechanism. This reduces the number of components that need to be assembled and installed, thereby increasing installation productivity and cost-effectiveness.
Solution Approach 2:
The insulating plate integrated into the housing structure provides the necessary electrical insulation automatically as part of the housing design, rather than requiring separate insulating components. This self-service approach simplifies the assembly process and improves installation efficiency.
Data Source
Figure 1
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AI summary
The invention relates to an electric earthing switch (1) to connect a line conductor of a gas insulated substation to the earth, comprising: - a metallic housing having two separate compartments: one, filled with insulating gas, for the main switch and the other, separated from insulating gas, for its drive mechanism, and a flange; - an insulating plate (2) to be tightened between the flange of the housing and a flange of a compartment enclosing the line; - a line contact (3a, 3b, 3c) carried by the insulating plate (2) and having an insert portion with a thread bolt passing through the insulating plate (2); - a fixed earth contact (8a) passing through the wall of the housing and having an outer and an inner portion relatively to the housing; - a sliding earth contact (9a) carried by the fixed earth contact (8a) to slide relatively to this fixed earth contact (8a); - a mechanism to actuate the sliding earth contact (9a) between an open position and a closed position; - the fixed earth contact (8a) extending perpendicular to the sliding direction (AX).