Optical Gas Sensor for Transformer Breakdown Prediction

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Solution Overview

Problem

Existing gas detection systems for electrical transformers are costly and inefficient in predicting breakdowns, as they rely on expensive relays and do not effectively monitor gaseous by-products formed during dielectric fluid degradation, leading to potential transformer failures and power outages.

Innovation Solution

A light-sealed optical gas sensor system with a membrane that reacts to gaseous by-products by changing opacity in response to specific wavelengths of light, coupled with a digital converter and transmitter to detect and communicate the presence and concentration of gases, allowing for early prediction of transformer failures.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If Buchholz relay is used to detect gas evolved during internal arcing, then transformer breakdown prediction is enabled, but the cost of the detection system increases

Engineering Contradiction:
Improvetransformer breakdown predictionVSAvoiddetection system cost
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces the mechanical Buchholz relay system with an optical detection system using a light source, optical fiber, and photodetector. This substitution eliminates the need for complex mechanical relay components while achieving gas detection through optical measurement of refractive index changes in the dielectric fluid.

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

Solution Approach 2:

The patent introduces an optical fiber as an intermediary element to transmit light through the dielectric fluid. The optical fiber serves as a mediator between the light source and photodetector, enabling remote gas detection through measurement of light transmission properties without direct mechanical contact with the fluid.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If traditional gas detection methods are used, then gas detection capability is provided, but the response time and detection sensitivity are insufficient

Engineering Contradiction:
Improvegas detection sensitivityVSAvoiddetection response time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent replaces slow mechanical gas sampling and analysis methods with optical detection. The optical system provides real-time measurement of gas concentration through refractive index changes, eliminating mechanical delays and achieving rapid response times suitable for early fault detection.

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

Solution Approach 2:

The patent changes the detection parameter from direct gas concentration measurement to refractive index measurement of the dielectric fluid. This parameter change enables continuous real-time monitoring with high sensitivity, as the refractive index changes continuously with gas concentration without requiring mechanical sampling intervals.

Inventive Principle:
Principle #35Parameter changes

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 system provides a cost-effective and efficient means to detect gaseous by-products, enabling timely maintenance and preventing transformer failures, thereby extending equipment life and reducing operational losses.

Implementation Method 1

a membrane which reacts to gaseous by-products by changing opacity in response to specific wavelengths of light

Methodology Applied
Scientific EffectOptical absorption: Absorption (EM radiation)

Data Source

PatentEP2490011B1Optical gas sensor for use with electrical equipment and method for detecting gas in electrical equipment using said gas sensor
Publication Date: 2020.09.09 GENERAL ELECTRIC CO
  • EP2490011B1 patent drawingFigure 1
  • EP2490011B1 patent drawingFigure 2

AI summary

An apparatus for use in detecting gaseous bi-products (23), in particular hydrogen gas (23), in electrical equipment, such as an oil-cooled transformer (20), is provided. The apparatus includes a light source (13), a photocell (14), and a membrane (12) interposed between the light source (13) and the photocell (14), such that interaction of the membrane (12) and a gaseous bi-product (23) at least one of prevents and allows light communication between the light source (13) and the photocell (14).