• 한국전기전자재료학회논문지
• /
• 제23권5호
• /
• pp.413-417
• /
• 2010

Line to ground faults by deterioration of insulators has frequently occurred in power system, and the main cause is surface contamination of the insulators. The contamination of insulator is analyzed by monitoring the surface leakage current flowing them. The suspension insulator is monitored by installation of a zero-phase current sensor(ZCT), but the line-post insulator is impossible to apply the same method because of its large diameter structure. This paper proposed a detection method of surface leakage current for a line-post insulator, and it can easily be applied to new and/or built insulators. The leakage current is indirectly calculated from the potential difference between the metal electrode attached on the surface of insulator and the ground connector. To evaluate the performance of the proposed method, the leakage current is compared as a function of contamination condition controlled by the density of NaCl solution. The leakage current is proportioned to the density of NaCl solution, and the voltage detected by the electrode showed the same trend. From the experimental results, we designed and fabricated a monitoring device which is composed of a detection electrode, signal converter, microprocessor, and ZigBee, and its measurement range is $10{\mu}A{\sim}5mA$.

• 한국정보통신학회논문지
• /
• 제24권9호
• /
• pp.1231-1240
• /
• 2020

상수도 배관은 땅속에 매설되어 있어서 배관의 노후화에 따른 누수를 맨눈으로 탐지하기가 불가능하며, 누수음을 감지함으로써 배관의 누수를 탐지하는 기술이 주로 사용된다. 본 논문에서는 상수도 배관의 양단에 두 개의 가속도계를 부착·취득한 데이터 간의 도달 시간 차이를 계산하여 누수 지점을 탐지하는 알고리즘을 개발하였다. 배관의 누수 시험은 17.2m의 배관에 4.3m, 8.6m, 12.9m 지점에 밸브를 설치하고, 밸브의 개도율을 30%, 70%로 변경해 가면서 누수 지점을 분석하였으며, 밸브가 30%, 70%씩 개방된 정도의 배관 내 압력 강하에 대해서는 누수를 탐지할 수 있는 것으로 확인되었다. 초기 단계의 누수를 탐지하는 것이 매우 중요하며, 본 연구에서 적용한 알고리즘으로부터 초기의 누수 지점의 탐지가 가능할 것으로 판단된다.

• 한국수자원학회:학술대회논문집
• /
• 한국수자원학회 2019년도 학술발표회
• /
• pp.160-160
• /
• 2019

Water is a limited source that needs to be properly managed and distributed to the ever-growing population of the world. Rapid urbanization and development have increased the overall water demand of the world drastically. However, there is loss of billions of liters of water every year due to leakages in water distribution systems. Such water loss means significant financial loss for the utilities as well. World bank estimates a loss of $14 billion annually from wasted water. To address these issues and for the development of efficient and reliable leakage management techniques, high efforts have been made by the researchers and engineers. Over the past decade, various techniques and technologies have been developed for leakage management and leak detection. These include ideas such as pressure management in water distribution networks, use of Advanced Metering Infrastructure, use of machine learning algorithms, etc. For leakage detection, techniques such as acoustic technique, and in recent yeats transient test-based techniques have become popular. Smart Water Grid uses two-way real time network monitoring by utilizing sensors and devices in the water distribution system. Hence, valuable real time data of the water distribution network can be collected. Best results and outcomes may be produced by proper utilization of the collected data in unison with advanced detection and management techniques. Long term reduction in Non Revenue Water can be achieved by detecting, localizing and repairing leakages as quickly and as efficiently as possible. However, there are still numerous challenges to be met and future research works to be conducted in this field.

• 대한전기학회논문지:전기물성ㆍ응용부문C
• /
• 제52권10호
• /
• pp.469-475
• /
• 2003

Resistive leakage current flowing ZnO blocks increases with its ages, which is an important indicator of arrester deterioration. However, a complicated circuitry is essential to measure the resistive leakage current included in the total leakage current, and the difficult handling of the measurement makes few applications to the fields. In this paper, we propose a resistive leakage current measurement device which is composed of a current detection circuit and an analysis program operated on a microprocessor. The device samples the input leakage current waveform digitally, and discriminate the zero-cross and the peak point of the waveform to analyze the current amplitude vs. phase. The capacitive leakage current is then eliminated from the total leakage current by using an algorithm to extract the resistive leakage current only. Also, the device can be operated automatically and manually to analyze the resistive leakage current even when the leakage current waveform is distorted due to various types of arrester deterioration. To estimate the performance of the device, we carried out a test on ZnO blocks and lightning arresters. From the results, it is confirmed that the device could analyze most parameters needed for the arrester diagnostics such as total leakage current. resistive leakage current, and the $3^rd$ harmonic leakage current.

• 한국지반공학회논문집
• /
• 제17권6호
• /
• pp.225-233
• /
• 2001

본 논문에서는 격자망식 전선배치에 의한 침출수 누출감지시스템을 개발하기 위하여 현장모형시험을 통하여 적용성을 평가하였으며, 전기회로시험을 통하여 격자망 전선 배치에서 발생하는 전기회로적 효과를 파악하고자 하였다. 침출수는 전기저항을 감소시키기 때문에 누출지점에서는 다른 지점에 비해 낮은 전기저항값을 나타내었다. 따라서, 전기저항을 측정하는 본 누출감지시스템에 의하여 임의 지점에서 발생하는 침출수의 누출 감지가 가능하였으며, 평면적 분포도를 통하여 누출위치의 파악이 가능하였다. 전기저항이 감소된 지점과 동일한 전선상에 위치한 다른 센서에 서의 측정값도 약간 감소하는 경향을 나타내었으나, 이는 저항이 작은 곳으로 전류의 흐름이 발생하는 전기회로적 효과로 설명할 수 있었다.

• 전기학회논문지
• /
• 제66권10호
• /
• pp.1445-1453
• /
• 2017

In this paper, we propose a fault detection model based on multi-layer neural network using data mining technique for faults due to boiler tube leakage in a thermal power plant. Major measurement data related to faults are analyzed using statistical methods. Based on the analysis results, the number of input data of the proposed fault detection model is simplified. Then, each input data is clustering with normal data and fault data by applying K-Means algorithm, which is one of the data mining techniques. fault data were trained by the neural network and tested fault detection for boiler tube leakage fault.

• 설비공학논문집
• /
• 제20권7호
• /
• pp.508-516
• /
• 2008

Fault detection and diagnosis(FDD) system is beneficial in equipment management by providing the operator with tools which can help find out a failure of the system. An experimental study has been performed on fault detection and diagnosis method for a water chiller. Bayes classifier, which is one of classical pattern classifiers, is adopted in deciding whether fault occurred or not. Failure modes in this study include refrigerant leakage, decrease in mass flow rate of the chilled water and cooling water, and sensor error of the cooling water inlet temperature. It is possible to detect and diagnose faults in this study by adopting FDD algorithm using only four parameters(compressor outlet temperature, chilled water inlet temperature, cooling water outlet temperature and compressor power consumption). Refrigerant leakage failure is detected at 20% of refrigerant leakage. When mass flow rate of the chilled and cooling water decrease more than 8% or 12%, FDD algorithm can detect the faults. The deviation of temperature sensor over $0.6^{\circ}C$ can be detected as fault.

• Investigative Magnetic Resonance Imaging
• /
• 제17권2호
• /
• pp.149-153
• /
• 2013

척추 수술의 합병증으로 뇌척수액 누출이 발생할 수 있는데 이를 영상학적으로 진단하는 것은 어려움이 있다. 이 연구에서는 자기공명척수조영술을 이용하여 척추 수술 후 뇌척수액 누출을 확인하였던 두 환자의 증례를 보고하고자 한다. 두 환자는 각기 요추 추간판 절제술과 척추 수막종 제거술을 받은 뒤 심한 두통을 호소하였다. 두 환자의 자기공명척수조영영상에서 척추 뇌수막액 누출 부위가 확인되었고, 이에 대해 환자들은 각각 epidural blood patch와 재수술을 받았다. 이 두 사례에서 자기공명척수조영술은 척추 뇌수막액의 누출 부위를 정확히 보여주었고, 척수강과 가성수막류 (pseudomeningocele) 사이의 교통로를 잘 나타내주었다. 척수 수술 후 뇌수막액 누출을 확인하기 위한 검사로 자기공명척수조영술이 유용한 것으로 생각된다.

• 대한전기학회논문지:시스템및제어부문D
• /
• 제53권3호
• /
• pp.161-165
• /
• 2004

In this paper, we have designed the ground faults detection and interrupting controller at normal condition of AC 120v to 240v rating voltage. Ground faults in electrical network have the characteristics of low current, 60㎐ frequency to 2㎑frequency. The load condition are no load and 20A load. The trip level of the controller is 6㎃ with ground faults. The Controller algorithm is implemented using pic16c71 microprocessor.

• International journal of advanced smart convergence
• /
• 제8권2호
• /
• pp.77-87
• /
• 2019

One of important concerns in information security is to control information flow. It is whether to protect confidential information from being leaked, or to protect trusted information from being tainted. In this paper, we present Piosk (Physical blockage of Information flow Kiosk) that addresses both the problems practically. Piosk can forestall and prevent the leakage of information, and defend inner tangible assets against a variety of malwares as well. When a visitor who carries a re-writable portable storage device, must insert the device into Piosk installed next to the security gate. Then, Piosk scans the device at the very moment, and detects & repairs malicious codes that might be exist. After that, Piosk writes the contents (including sanitized ones) on a new read-only portable device such as a compact disk. By doing so, the leakage of internal information through both insiders and outsiders can be prevented physically. We have designed and prototyped Piosk. The experimental verification of the Piosk prototype implementation reveals that, Piosk can accurately detect every malware at the same detection level as Virus Total and effectively prevent the leakage of internal information. In addition, we compare Piosk with the state-of-the-art methods and describe the special advantages of Piosk over existing methods.