Insulated Switchgear Gas Quantity Calibration for Early Leak Detection

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Solution Overview

Problem

Existing methods for monitoring gas quantity in gas insulated switchgear tanks face challenges in accuracy due to temperature gradients and environmental influences, making it difficult to detect small leaks promptly.

Innovation Solution

A method using embedded gas temperature and pressure sensors, combined with an ambient temperature sensor, applies a calibration phase to determine a corrected gas temperature model that ensures consistent gas quantity calculations, enhancing accuracy without additional hardware.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If gas quantity is monitored using external temperature and pressure sensors, then the monitoring system is simple to implement, but the measurement accuracy is insufficient due to temperature gradients and environmental influences

Engineering Contradiction:
Improvegas quantity measurement accuracyVSAvoidsensor configuration complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent applies preliminary action by performing a calibration phase before actual gas quantity monitoring. During this phase, multiple temperature measurements are taken at different times, and a correction factor is calculated and stored. This pre-computed correction factor compensates for temperature gradient effects during subsequent measurements, improving accuracy without adding complex real-time correction hardware.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent replaces complex multi-sensor mechanical arrangements with a computational approach. Instead of using multiple temperature sensors positioned throughout the tank to directly measure temperature gradients, the system uses a single external temperature sensor combined with mathematical correction based on calibration data, substituting physical measurement complexity with algorithmic processing.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Measurement precision

If multiple temperature sensors are distributed throughout the tank to measure temperature gradients, then measurement accuracy improves, but device complexity and cost increase

Engineering Contradiction:
Improvegas temperature measurement accuracyVSAvoidsensor quantity and configuration
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent extracts the temperature sensing function from the gas interior to the external environment. By placing the temperature sensor outside the tank and using calibration-based correction, the system eliminates the need for multiple internal temperature sensors while maintaining measurement accuracy through mathematical compensation of temperature gradient effects.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent creates a virtual representation of the internal gas temperature by combining external temperature sensor readings with calibration-derived correction factors. This copied temperature information accurately reflects internal conditions without requiring direct physical contact with the gas, avoiding the complexity of multiple internal sensors.

Inventive Principle:
Principle #26Copying

3Reliability

If gas quantity monitoring is performed continuously with high precision, then small leaks can be detected early, but the system requires more complex calibration and maintenance

Engineering Contradiction:
Improveleak detection capabilityVSAvoidcalibration and maintenance simplicity
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The patent performs calibration during the commissioning phase or after major maintenance, storing correction factors that remain valid for extended periods. This preliminary calibration action enables continuous reliable monitoring without requiring frequent recalibration, maintaining leak detection capability while minimizing maintenance burden.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system performs self-calibration by automatically computing correction factors from temperature measurements taken during the calibration phase. This self-service approach eliminates the need for manual calibration procedures, simplifying operation and maintenance while ensuring accurate leak detection capability.

Inventive Principle:
Principle #25Self-service

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 method improves gas quantity calculation accuracy, enabling early detection of leaks by minimizing discrepancies in gas quantity measurements, ensuring reliable operation of the switchgear.

Implementation Method 1

determine a gas quantity contained in the tank from a gas state equation based on the acquired gas pressure, and on a corrected gas temperature model

Methodology Applied
Scientific EffectGas state equation: Boyle's Law

Implementation Method 2

a gas temperature measured by an embedded gas temperature sensor

Methodology Applied
Scientific EffectTemperature sensing: Thermal Radiation

Implementation Method 3

a gas pressure measured by an embedded gas pressure sensor

Methodology Applied
Scientific EffectPressure sensing: Pressure Gradient

Data Source

PatentEP4462095B1Method for determining a quantity of gas contained in an insulated switchgear
Publication Date: 2026.02.25 SCHNEIDER ELECTRIC IND SAS
  • EP4462095B1 patent drawingFigure 1
  • EP4462095B1 patent drawingFigure 2~3
  • EP4462095B1 patent drawingFigure 4~5

AI summary

The invention relates to a method for determining a quantity (N) of a gas (G) contained in a tank (1) of a gas insulated switchgear (2), the method comprising during a calibration phase: (i) acquiring a plurality (n) of successive sets of calibration samples (S1, S2, ..., Sn) comprising a gas pressure (P1, P2, ..., Pn), a gas temperature (T1, T2, ..,Tn) and an ambient temperature (TA1, TA2, ...,TAn), (ii) for each set of calibration samples (S1, S2,..., Sn), determining a corrected gas temperature (Tcor1, Tcor2, ..., Tcorn) from a model (M) and (iii) determine a gas quantity (N1, N2, ...,Nn) contained in the tank (1) from a gas state equation (E) and from the determined corrected gas temperature (Tcor1, Tcor2, ...,Tcorn), the method further comprising during a measurement phase: (v) determining a corrected gas temperature (Tcor) from the model (M) and from an acquired gas temperature (Tsens), gas pressure (Psens) and ambient temperature (Tamb), (vi) determining the quantity (N) from the gas state equation (E) and from the determined corrected gas temperature (Tcor).