Transformer Diagnostics via Harmonic Current Analysis

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Solution Overview

Problem

Current diagnostic methods for high voltage transformers are inadequate in identifying issues, as they fail to accurately locate and characterize problems in about 20-30% of cases, leading to potential catastrophic failures.

Innovation Solution

A diagnostic system that drives transformer windings with a sinusoidal AC voltage and measures harmonic components of the excitation current, comparing these parameters with benchmark data to determine if the transformer is functioning properly or has defects like shorted windings, using a system comprising a voltage generator, switch section, harmonic analyzer, and processor for precise analysis.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If routine diagnostic testing with AC voltage and power frequency component measurement is performed, then diagnostic capability is provided, but measurement precision and problem identification accuracy deteriorate (20-30% failure to identify problems)

Engineering Contradiction:
Improveproblem identification accuracyVSAvoiddiagnostic reliability
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent changes the measurement parameters from power frequency component magnitude to harmonic component magnitudes (3rd, 5th, 7th, 9th harmonics). This parameter transformation enables accurate identification of transformer defects that were previously undetectable, resolving the contradiction between measurement precision and diagnostic reliability.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent transitions from measuring a single parameter (power frequency component) to measuring multiple harmonic parameters (3rd, 5th, 7th, 9th harmonics). This dimensional expansion in the measurement space provides comprehensive diagnostic information, eliminating the 20-30% failure rate in problem identification.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Measurement precision

If harmonic component measurement and benchmark comparison is performed, then diagnostic accuracy is improved, but device complexity increases

Engineering Contradiction:
Improvedefect identification accuracyVSAvoiddiagnostic system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The diagnostic system is designed to measure multiple harmonic components (3rd, 5th, 7th, 9th) simultaneously using a unified measurement and analysis platform. This multi-functional approach achieves comprehensive defect identification without proportionally increasing system complexity, as the same hardware infrastructure handles all harmonic measurements.

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

Solution Approach 2:

The patent uses benchmark transformers with known good performance characteristics as reference copies. By comparing measured harmonic parameters against these benchmarks, the system achieves high diagnostic accuracy without requiring complex analysis algorithms, simplifying the overall system while maintaining precision.

Inventive Principle:
Principle #26Copying

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 more comprehensive diagnostic analysis, accurately identifying transformer defects by comparing measured harmonic patterns with benchmark data, enhancing the ability to prevent transformer failures and ensuring system reliability.

Implementation Method 1

drive one or more windings or phases of a transformer with a sinusoidal AC voltage and to measure characteristic parameters of an excitation current that flows into the windings/phases

Methodology Applied
Scientific EffectElectromagnetic Induction: Electromagnetic Induction

Implementation Method 2

determine a magnitude of a harmonic component of the exciting current

Methodology Applied
Scientific EffectFourier Analysis:

Data Source

PatentEP3120162B1System and method for performing transformer diagnostics
Publication Date: 2021.06.09 DOBLE ENGINEERING CO
  • EP3120162B1 patent drawingFigure 1
  • EP3120162B1 patent drawingFigure 2A~2B
  • EP3120162B1 patent drawingFigure 3

AI summary

A method for performing diagnostics on a transformer includes generating, by a voltage generator, an AC voltage and applying the AC voltage to a winding or phase of the transformer. Current flowing from the generator to the winding or phase is decomposed into a plurality of harmonic components. Respective magnitudes of the plurality of harmonic components are compared with corresponding magnitudes of harmonic components associated with one or more benchmark transformers of a known condition to determine whether the condition of the transformer matches the condition of one or more benchmark transformers.