DFIG Wye-Ring Crack Detection via Phase Voltage Fourier Analysis

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Solution Overview

Problem

Current methods for detecting defects in the wye-ring of a doubly-fed induction generator (DFIG) rotor in wind turbines require offline testing, leading to energy loss and increased maintenance costs due to the need for partial dismantling and shutdown of the turbine.

Innovation Solution

A fault detection system using three sensors to measure voltages of each phase of the wye-ring, applying a Fourier transform to identify conditions, and providing an alert system to indicate mechanical issues without requiring the turbine to be taken offline.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If offline testing is performed to detect wye-ring cracks, then measurement precision is improved, but productivity deteriorates due to turbine shutdown

Engineering Contradiction:
Improvecrack detection accuracyVSAvoidenergy production
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

The system performs preliminary monitoring and detection during normal operation using voltage measurements and Fourier transform analysis to identify crack conditions before they cause failures, eliminating the need for offline testing and maintaining continuous productivity

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent replaces the mechanical offline testing process (which requires shutdown and disassembly) with an electrical monitoring system that continuously analyzes voltage signals during operation, substituting physical inspection with signal processing-based detection

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

2Reliability

If the turbine is taken offline for testing, then reliability is improved through accurate defect detection, but loss of time increases due to shutdown and maintenance downtime

Engineering Contradiction:
Improvewye-ring condition assessmentVSAvoidturbine downtime
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The monitoring system enables continuous assessment of wye-ring condition during normal turbine operation, maintaining the continuity of useful action by eliminating shutdowns for inspection and allowing proactive maintenance scheduling that minimizes downtime

Inventive Principle:
Principle #20Continuity of useful action

3Measurement precision

If partial dismantling is performed for testing, then measurement precision is improved, but device complexity increases due to disassembly and reassembly requirements

Engineering Contradiction:
Improvecrack detection capabilityVSAvoidmaintenance procedure complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent extracts the detection function from the physical structure by using voltage measurements and signal processing to identify cracks without requiring physical access to or disassembly of the wye-ring, simplifying the maintenance procedure while maintaining detection capability

Inventive Principle:
Principle #2Taking out (Extraction)

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

Enables early detection of defects, preventing unexpected arcing and reducing repair costs by allowing for proactive maintenance, thereby minimizing downtime and financial losses.

Implementation Method 1

The alert system is configured to apply a Fourier transform to the respective measured voltages of each phase of the at least three electrical phases of the wye-ring

Methodology Applied
Scientific EffectFourier transform:

Data Source

PatentEP3339638B1Systems for crack detection in doubly-fed induction generators
Publication Date: 2022.01.26 GENERAL ELECTRIC CO
  • EP3339638B1 patent drawingFigure 1
  • EP3339638B1 patent drawingFigure 2
  • EP3339638B1 patent drawingFigure 3~4

AI summary

A fault detection system (228) for a wind turbine (100) includes a doubly-fed induction generator (DFIG) (132). The DFIG (132) includes a wye-ring (300) configured for at least three electrical phases (506). The fault detection system (228) includes a data acquisition system (218) including at least three sensors (220). Each sensor (220) of said at least three sensors (220) is configured to electrically couple with and measure a respective voltage of each phase (506) of the at least three electrical phases (506) of the wye-ring (300). The fault detection system (228) further includes an alert system (224) coupled to said data acquisition system (218). The alert system (224) is configured to apply a Fourier transform to the respective measured voltages of each phase (506) of the at least three electrical phases (506) of the wye-ring (300). The alert system (224) is further configured to provide an indication of a condition of the wye-ring (300) based upon the transformed measured voltages.