Insulation Fluid Component Grouping for Breakdown Strength

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Solution Overview

Problem

Existing methods for monitoring the dielectric breakdown strength of multi-component insulation fluids in electrical apparatuses do not effectively determine this critical parameter, which is essential for assessing the operating state of gas-insulated electrical equipment, particularly in high voltage switchgears.

Innovation Solution

A method that assigns components of the insulation fluid to two groups based on their molecular masses and critical field strengths, using measurement variables like pressure, temperature, and density to derive the dielectric breakdown strength, thereby simplifying the calculation by reducing the number of unknowns and enhancing insulation performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If multi-component fluid mixtures are used as insulation fluid, then the dielectric breakdown strength can be optimized for specific applications, but the determination of dielectric breakdown strength becomes more complicated due to concentration ratio dependencies

Engineering Contradiction:
Improvedielectric breakdown strengthVSAvoidcomplexity of determining dielectric breakdown strength
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent segments the multi-component insulation fluid into distinct components, each with assigned critical field strength values. By breaking down the complex mixture into individual measurable components and their concentrations, the system can determine dielectric breakdown strength through a structured calculation process rather than treating the mixture as an undifferentiated whole.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system uses measured concentrations of insulation fluid components as feedback to calculate and determine the dielectric breakdown strength. The measurement results directly inform the calculation through the formula E_bd = Σ(c_i × E_crit,i), creating a feedback loop where component analysis leads to breakdown strength determination.

Inventive Principle:
Principle #23Feedback

2Measurement precision

If conventional monitoring methods are used for multi-component insulation fluids, then component proportions can be monitored, but the dielectric breakdown strength cannot be determined

Engineering Contradiction:
Improvecomponent proportion monitoringVSAvoiddielectric breakdown strength information
Core Design Contradiction:
Measurement precisionVSLoss of information

Solution Approach 1:

The patent merges component proportion monitoring with dielectric breakdown strength determination into a single integrated system. By combining the measurement of component concentrations with the calculation of dielectric breakdown strength using the critical field strength formula, the system simultaneously achieves both functions that were previously separate or incompatible.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The system performs multiple functions using the same measurement infrastructure: it monitors component proportions, calculates dielectric breakdown strength, and assesses the operational state of the electrical apparatus. This multi-functional approach eliminates the need for separate monitoring systems.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Device complexity

If single component insulation fluids are used, then the determination of dielectric breakdown strength is simpler, but alternative fluids with better environmental properties become limited

Engineering Contradiction:
Improvesimplicity of determinationVSAvoidavailability of alternative insulation fluids
Core Design Contradiction:
Device complexityVSAdaptability or versatility

Solution Approach 1:

The patent changes the approach from measuring physical properties directly to measuring component concentrations and using calculated critical field strength values. This parameter transformation allows the system to handle any multi-component mixture by assigning and calculating E_crit,i values for each component, making the method adaptable to various fluid compositions without requiring direct measurement of breakdown strength.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP2844998B1Method and device for determining an operating parameter of a fluid insulated electrical apparatus
Publication Date: 2016.04.06 ABB TECHNOLOGY AG
  • EP2844998B1 patent drawingFigure 1~2
  • EP2844998B1 patent drawingFigure 3~4
  • EP2844998B1 patent drawing

AI summary

The invention relates to a method for deriving at least one operating parameter P of a fluid-insulated electrical apparatus (1), in particular of gas-insulated switchgear (1). The operating parameter P is dependent on a dielectric breakdown strength Ebd of an insulation fluid (10) of the electrical apparatus (1). The insulation fluid (10) comprises at least three components X, Y, and Z that are assigned to at least a first and a second component group A and B such that at least one component group comprises at least two components. The component groups A and B differ in their weighted average values of the molecular masses of the components in the respective component groups. Then, at least one quantity which is indicative of the concentration cA of the first component group A and of the concentration cB of the second component group B is determined from the insulation fluid (10), e.g. by measuring one or more measurement variables (p, p, T, lambda, eta, cs) by means of one or more sensors (30). The operating parameter P is then derived using the at least one quantity.