GIS Junction Sealing Through Vented Inter-Seal Injection
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Solution Overview
Problem
Existing methods for sealing leaks in gas-insulated substation (GIS) compartments are inefficient, particularly in maintaining gas pressure and electrical voltage without disrupting operations, and often fail to completely expel pre-existing gas from the inter-seal volume.
Innovation Solution
A method involving the injection of a sealing product into the inter-seal volume using a leakage recovery duct, accompanied by pre-drilling a vent duct from the outside to the inter-seal volume to ensure complete expulsion of pre-existing gas and to allow the sealing product to exit, thereby ensuring a stable and complete seal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a strip of fabric is wound over the flanged junction to form a tourniquet for external sealing, then the sealing appears simple to install, but the flanged junction cannot be accessed or dismantled at a later date and the sealing is not durable under pressure
Solution Approach 1:
The sealing system is segmented into multiple components: an inner seal, an outer seal, and an inter-seal volume. This segmentation allows the sealing function to be distributed and maintained without compromising future accessibility, as each seal can be independently assessed or replaced through the leakage recovery duct.
Solution Approach 2:
The leakage recovery duct serves as an intermediary access point that enables maintenance and sealing operations without requiring dismantling of the flanged junction. By providing intermediate access to the inter-seal volume, it resolves the contradiction between maintaining simple installation procedures and preserving future accessibility for maintenance.
2Reliability
If an enclosure is created around the flange junction with hermetic shuttering for external sealing, then the enclosure can be heavy and cumbersome or even impossible to install, but the gas leakage remains confined in an enclosure at pressure
Solution Approach 1:
The harmful function of creating a heavy external enclosure is extracted and replaced by an internal sealing system. The sealing function is taken out from the external structure and implemented within the inter-seal volume between the flanged junction components, eliminating the need for cumbersome external shuttering while maintaining sealing effectiveness.
Solution Approach 2:
The sealing system uses a nested structure where the inner seal is positioned within the inter-seal volume, which is itself bounded by the outer seal and the flanged junction components. This nested arrangement achieves reliable sealing without requiring external enclosures, as each sealing element is contained within the existing structural boundaries.
3Reliability
If a sealing product is injected between the flanges of the junction through a perforated flange, then the product can fill gaps and stop leakage, but machining specifically designed for injection is required
Solution Approach 1:
The leakage recovery duct is designed with multi-functionality: it serves both as a monitoring device for detecting leaks and as an injection pathway for delivering sealing product to the inter-seal volume. This universal design eliminates the need for separate injection machining while maintaining effective sealing capability.
Solution Approach 2:
The existing leakage recovery duct structure is utilized to serve the additional function of product injection. The system is designed to be self-sufficient by using its own existing pathways (the leakage recovery duct) for both detection and sealing operations, eliminating the need for additional specialized machining.
4Reliability
If the GIS compartment is dismantled to revise bearing surfaces and change mechanical seals, then the ideal sealing solution can be achieved, but the entire structure and power transmission network become unavailable causing major inconvenience
Solution Approach 1:
The sealing product is injected into the inter-seal volume through the leakage recovery duct as a preliminary action that creates an effective seal without requiring dismantling. This preliminary sealing action maintains the mechanical seals in place while restoring sealing functionality, thereby avoiding the need for time-consuming dismantling and reassembly operations.
Solution Approach 2:
The leakage recovery duct serves as an intermediary access pathway that enables sealing operations without requiring dismantling of the flanged junction. By providing intermediate access to the inter-seal volume, it allows maintenance personnel to inject sealing product and restore sealing functionality while the GIS compartment remains in service, eliminating operational downtime.
5Productivity
If sealing methods are applied that do not require dismantling or operating interruption, then operational continuity is maintained, but the pre-existing gas in the inter-seal volume must be completely expelled and replaced by the sealing product
Solution Approach 1:
The injection of sealing product through the leakage recovery duct utilizes fluid pressure principles to completely expel pre-existing gas from the inter-seal volume. The sealing product is injected under pressure, ensuring that all residual gas is displaced and the inter-seal volume is fully filled, thereby achieving complete and reliable sealing while maintaining operational continuity.
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
This method effectively seals leaks in GIS compartments without requiring dismantling of the GIS compartment, maintains gas pressure and electrical voltage, and ensures the absence of residual gas bubbles in the inter-seal volume, thus providing a durable and efficient sealing solution.
Implementation Method 1
a injection of a sealing product into the inter-seal volume by use of a leakage recovery duct arranged in the thickness of the compartment, this duct opening into the inter-seal volume
Data Source
AI summary
A method for sealing a junction with a contact surface and counter-contact surface of an element of a compartment of a gas-insulated substation includes injecting a sealing product into an inter-seal volume formed between the contact surface and counter-contact surface by using a leakage recovery duct opening into the inter-seal volume. Prior to injection, a vent duct different from the leakage recovery duct is drilled from the outside of the compartment into the inter-seal volume. During injection, the sealing product is injected under pressure into the inter-seal volume until it fills it, then exits through the vent duct.