• 대한전기학회논문지:전력기술부문A
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• 제48권3호
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• pp.184-189
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• 1999

In this paper, we develope a diagnosis device for ZnO arrester by detecting the leakage current in service. To diagnose the deterioration of ZnO arrester, the device detects the total leakage current which flows between an arrester and ground, and analyzes the resistive current(third harmonic current) which is an indicator of deterioration of ZnO arrester. We use the optical cable which can transfer a detected data without a noise, also use a microprocessor for a data storage, processing, and trend analysis. Experiment are executed to verify its performance in laboratory and the results show that the diagnosis device exactly detects the total leakage current and the resistive current, so it can diagnose the deterioration of ZnO arrester. Also the leakage current of ZnO arrester is detected using the developed diagnostic device in field, these results are presented.

• Nuclear Engineering and Technology
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• 제52권8호
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• pp.1689-1696
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• 2020

In this study, we developed a fiber-optic humidity sensor (FOHS) system for the monitoring and detection of coolant leakage in nuclear power plants. The FOHS system includes an FOHS, a spectrometer, a halogen white-light source, and a Y-coupler. The FOHS is composed of a humidity-sensing material, a metal tube, a multi-mode plastic optical fiber, and a subminiature version A (SMA) fiber-optic connector. The humidity-sensing material is synthesized from a mixture of polyvinylidene fluoride (PVDF) in dimethyl sulfoxide (DMSO) and hydroxyethyl cellulose (HEC) in distilled water. We measured the optical intensity of the light signals reflected from the FOHS placed inside the humidity chamber with relative humidity (RH) variation from 40 to 95%. We found that the optical intensity of the sensing probe increased linearly with the RH. The reversibility and reproducibility of the FOHS were also evaluated.

• Smart Structures and Systems
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• 제22권2호
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• pp.239-247
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• 2018

A magnetic flux leakage (MFL) method was applied to detect and quantify defects in a steel bar. A multi-channel MFL sensor head was fabricated using Hall sensors and magnetization yokes with permanent magnets. The MFL sensor head scanned a damaged specimen with five levels of defects to measure the magnetic flux density. A series of signal processing procedures, including an enveloping process based on the Hilbert transform, was performed to clarify the flux leakage signal. The objective damage detection of the enveloped signals was then analyzed by comparing them to a threshold value. To quantitatively analyze the MFL signal according to the damage level, five kinds of damage indices based on the relationship between the enveloped MFL signal and the threshold value were applied. Using the proposed damage indices and the general damage index for the MFL method, the detected MFL signals were quantified and analyzed relative to the magnitude of the damage increase.

• 상하수도학회지
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• 제29권3호
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• pp.415-425
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• 2015

Aging water pipe networks hinder efficient management of important water service indices such as revenue water and leakage ratio due to pipe breakage and malfunctioning of pipe appurtenance. In order to control leakage in water pipe networks, various methods such as the minimum night flow analysis and sound waves method have been used. However, the accuracy and efficiency of detecting water leak by these methods need to be improved due to the increase of water consumption at night. In this study the Principal Component Analysis (PCA) technique was applied to the night water flow data of 426 days collected from a water distribution system in the interval of one hour. Based on the PCA technique, computational algorithms were developed to narrow the time windows for efficient execution of leak detection job. The algorithms were programmed on computer using the MATLAB. The presented techniques are expected to contribute to the efficient management of water pipe networks by providing more effective time windows for the detection of the anomaly of pipe network such as leak or abnormal demand.

• 정보처리학회 논문지
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• 제13권2호
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• pp.41-47
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• 2024

시간 및 주파수 영역에서 각각 학습한 모델 간에 성능 차이가 발생할 경우, 앙상블을 수행하더라도 개별 모델 간의 성능 불균형으로 인하여 앙상블의 성능이 오히려 저하되는 현상을 확인할 수 있었다. 따라서, 본 논문은 시간 영역과 주파수 영역에서 특징을 추출하고, 이들을 융합한 단계적 학습 방법을 통해 파이프라인 누출 감지의 정확성을 높이기 위한 누출판별 기법을 제안한다. 이 방법은 두 단계의 학습 과정으로 이루어지며, 먼저, 단계 1에서는 시간 영역과 주파수 영역에서 독립적으로 모델 학습을 수행하여 도메인별로 주어진 데이터로부터 중요한 특징들을 효과적으로 추출하도록 하였다. 단계 2에서는 사전학습 완료된 각 모델로부터 해당 분류기를 제거한 후, 두 도메인의 특징들을 서로 융합하고 새로운 분류기를 추가하여 재학습을 수행하였다. 본 논문에서 제안하는 전이학습 기반 특징융합 기법은 시간 및 주파수 영역에서 추출된 특징들을 융합하여 모델 학습을 수행함으로써, 두 영역의 특징이 상호 보완적으로 작용하여 모델이 다양한 정보를 활용함으로 인해 99.88%의 높은 정확도를 달성하여 파이프 누수 감지에 있어 우수한 성능을 입증하였다.

• 비파괴검사학회지
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• 제35권5호
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• pp.307-313
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• 2015

배관의 누설 검출은 주로 AE(acoustic emission) 센서와 같은 접촉식 센서가 이용되고 있다. 그러나 이러한 접촉식 센서는 고온이나 고방사능 지역에서 설치 및 운용의 어려움이 따른다. 이에 최근 원거리 감시 및 광역감시가 가능한 카메라를 이용한 누설 검출 방법에 대한 연구가 진행되어 왔다. 기존 카메라를 이용한 방법은 누설 검출을 위해 차영상 기법을 이용하고 있다. 그러나 이 방법은 누설뿐만 아니라 구조물의 진동이 누설로 검출되는 오류를 보이고 있다. 본 논문에서는 카메라를 이용한 누설 검출 방법에서 누설 검출 오류를 줄이기 위한 이동평균 차영상 및 히스토그램 분석법을 제안하였으며 실험을 통하여 성능을 평가하였다.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2010년도 하계학술대회 논문집
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• pp.113-114
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• 2010

정부의 친환경, 에너지절감 정책에 따라 누전차단 기능을 갖는 반도체 IC에 있어서도 고감도의 성능을 가지면서도 전력 소모가 적은 IC의 개발이 요구 되고 있다. 본 논문에서는 산업용 누전차단기(Earth Leakage Circuit Breaker)에 사용되는 핵심 반도체로서 고감도이면서도 저전력 소모를 하는 누전전류 검출 IC의 개발을 수행한다.

• 조명전기설비학회논문지
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• 제25권7호
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• pp.92-96
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• 2011

In this paper, in order to reduce the electrical disaster such as electrical fire at traditional markets, we need to develop the ESMS(electrical safety monitoring system) which is able to monitor the power status of electrical equipments. Therefore, for solving the those problems, we developed the detection censor(ZCT, CT) and equipment of data analysis and transmission. The detection censor and equipment are able to monitor the electrical equipments condition(over current, leakage current, arc, etc.). We constructed Test-Bed for testing reliability of the ESMS and obtained certification. And we tested the over current, leakage current and arc under the normal condition.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 하계학술대회 논문집 C
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• pp.1966-1968
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• 2000

Globally, oil-filled paper-insulated cables and cross-linked polyethylene-insulated cables have been mainly applied for a underground power transmission line. The oil-filled cable has the hydraulic system in which insulating oil, expanded and contracted by temperature changes, is absorbed and supplied. This system enable us to detect oil leakages from the cable. But it has some problems such as difficulty in detecting minor leakages and a relatively long period of fault detecting. And so, this paper introduce a new leakage detection system, improved from the current one.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 학술회의 논문집 정보 및 제어부문 B
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• pp.417-420
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• 2003

In this paper, we have designed the ground faults detection and disconnection algorithm at normal rendition of AC 120V to 240V rating voltage. Ground faults in electrical network have the characteristics of low current, 60Hz frequency to 2kHz frequency. The load rendition are no load and 20A load. The controller have the trip level are 6mA with ground faults. Conventional controller does not have the miswiring condition. The Controller algorithm using pic16c71 microprotessor.