GIS Flange Bolt Strain Sensing for Gas Leak Localization
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Solution Overview
Problem
Existing gas pressure monitoring devices for gas insulated switchgear face challenges such as gas leaks at seal points, limited accuracy in detecting gas leaks due to low strain sensor sensitivity on rigid metal vessels, and high maintenance costs for regular inspections.
Innovation Solution
A gas pressure monitoring device that uses strain sensors installed on bolts fastening flanges of cylindrical vessels to measure stress changes, allowing accurate pressure monitoring and leak detection without modifying the existing setup, and a method to identify the position of gas leaks by comparing stress values across bolts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a pressure sensor is provided in each gas section and gas is led through piping to the external pressure sensor, then gas pressure can be monitored, but multiple seal portions are required which increase gas leak risk
Solution Approach 1:
The invention extracts the pressure sensing function from the gas-containing environment by using strain sensors on external bolts, eliminating the need for pressure sensors inside the gas sections and the associated piping and seals
Solution Approach 2:
The invention introduces bolts as an intermediary element that transmits the effect of internal gas pressure to external sensors, allowing indirect measurement of pressure without direct contact between sensors and gas
2Reliability
If strain sensors are attached to the outer face of the metal cylindrical vessel, then gas leak risk is reduced, but the change in output with respect to gas pressure change is small due to vessel rigidity
Solution Approach 1:
The invention applies strain sensors locally on the bolts rather than on the rigid vessel body, where the local stress concentration provides sufficient signal variation for accurate pressure measurement
Solution Approach 2:
The invention replaces direct mechanical pressure measurement on the vessel with indirect strain measurement on the bolts, which amplify the mechanical effect of pressure changes
3Reliability
If regular inspection of pressure gauge indication values is performed, then gas leak detection is achieved, but inspection costs and time consumption increase
Solution Approach 1:
The system enables continuous automatic monitoring of gas pressure through strain sensors on bolts, eliminating the need for manual regular inspections by inspection staff
Solution Approach 2:
The invention implements continuous pressure monitoring through the strain sensor system on bolts, replacing periodic manual inspections with uninterrupted automated measurement
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 provides low-cost, accurate gas pressure monitoring with reduced gas leak risk and identifies leak positions effectively, maintaining the integrity of the switchgear without additional installation work or costly modifications.
Implementation Method 1
a bolt with sensor, the bolt being at least one bolt of the plurality of bolts and including at least one sensor on each of an inner diameter side and an outer diameter side of a cylindrical vessel in the axial direction of the one bolt; a measurement recording unit that records reading values of the pressure gauge and output values of the sensor; and an evaluation unit that calculates relationship between the pressure of the insulating gas and stress acting on the bolt with sensor
Data Source
AI summary
A gas pressure monitoring device of a gas insulated switchgear (100) of the present invention includes at least two cylindrical vessels (21, 23) that configure the gas insulated switchgear (100) to receive an insulating gas to be at an internal pressure. The at least two cylindrical vessels (21, 23) have flanges (21a, 23a), and a plurality of bolts (11) that fasten the flanges of the at least two cylindrical vessels (21, 23). At least one bolt (11b) of the plurality of bolts (11) includes at least one sensor (1, 2) provided on the inner peripheral face thereof toward each of an inner diameter side and an outer diameter side of a cylindrical vessel (23) to measure strain acting in the axial direction of the at least one bolt (11b) with the sensor (1, 2). A pressure gauge (104) is installed on the cylindrical vessel (23) and reads pressure of the insulating gas when the insulating gas is sealed into the cylindrical vessel (23). A measurement recording unit (103) records pressure values output from the pressure gauge (104) and values output from the sensor (1, 2). An evaluation unit (106) calculates relationship between the pressure of the insulating gas and the stress acting on the at least one bolt (11b) with the sensor (1, 2) when the insulating gas is sealed into the cylindrical vessel (23), wherein, after an operation of the switchgear (100) is started, change in the pressure (ΔP) of the insulating gas in the cylindrical vessel (23) is estimated from change in the stress acting on the at least one bolt (11b) with the sensor (1, 2), so as to enhance monitoring the pressure of the insulating gas.