자기누설탐상법을 이용한 가스 배관 결함 추정에 관한 연구

다국어 초록 (Multilingual Abstract)

In general, In-Line Inspection(ILI) tool based on Magnetic Flux Leakage(MFL) technique is widely used to inspect buried gas pipeline. After inspection, the estimation and evaluation of defects are performed using the acquired MFL signal in order to repair the pipeline with defects. It is very important to analyze and estimate the MFL signal from defects as accurately as possible, because a lot of cost of repair is needed to repair the pipeline. But it is difficult to analyze MFL signal, because MFL signal has the nonlinear characteristics. Therefore, in this study, the estimation way to characterize a defect is described. In order to obtain the MFL signal from defect, MFL inspection runs were executed at Kogas Pipeline Simulation Facility(KPSF) including various artificial defects. And, 3 axis MFL signals were acquired from various defects. The length estimation of defect was performed using radial MFL signal, the width estimation was performed using wavelet transform method, and the depth estimation of defect was performed using axial MFL signal. When comparing measured size of defect with estimated size of one, the results show that the length estimation error is ±6.3mm, the width estimation error is ± 18.63mm, and the depth estimation error is ±8.3% thickness of pipewall at 80% confidence interval.

목차 (Table of Contents)

• Abstract
• 1. 서론
• 2. 자기누설 신호 특성
• 3. 자기누설 신호 획득 및 추출
• 4. 결함 크기 추정 방법
• 5. 결함 크기 추정 성능 결과
• 4. 결론
• 참고문헌