• 전기학회논문지P
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• 제57권2호
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• pp.202-208
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• 2008

Condition monitoring technologies allow achieving this goal by minimizing downtime through the integrated planning and scheduling of repairs indicated by condition monitoring techniques. Thermal runaways induced by conduction problems deteriorate insulating material and cause disruptive dielectric discharges resulting in arcing faults. Therefore, having the ability to directly measure the temperature of the contacts while in service will provide more information to determine the true condition of the equipment. It allows connective measures to be taken to prevent upcoming failure. Continuous temperature monitoring and event recording provides information on the energized equipment's response to normal and emergency conditions. On-line temperature monitoring helps to coordinate equipment specifications and ratings, determine the real limits of the monitored equipment and optimize facility operations. Using wireless technique eliminates any need for special cables and wires with lower installation costs if compared to other types of online condition monitoring equipment. In addition, wireless temperature monitoring works well under difficult conditions in strategically important locations. Wireless technology for on -line condition monitoring of energized equipment is applicable both as stand alone system and with an interface for power quality monitoring system. The paper presents the results of wireless temperature monitoring: of electrical equipment at a power plant.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 하계학술대회 논문집 A
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• pp.464-466
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• 2001

In this paper, we developed the on-line Data Aquisition System(DAS) of distribution transformers using the hardware and monitoring program. The DAS consists of the top oil temperature sensing part, ambient temperature sensing part, load current sensing part, acoustic emission peak-value sensing part, acoustic emission pulse counter part, micro-processor part and wireless communication part. The Monitoring System consists of the communication setting, online monitoring and database construction part. The DAS send the data acquired from the some sensors of the distribution transformers to the host PC. The monitoring program of the host PC stores the data to database. And the monitoring system estimates the loss of life time for distribution transformer from the DB. Thus, it could be managed the career and the functional lifetime of the transformer more efficiently than existing methodologies.

• Tribology and Lubricants
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• 제36권6호
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• pp.307-314
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• 2020

In this paper, studies on application cases of machine condition monitoring using oil sensors are reviewed. Owing to rapid industrial advancements, maintenance strategies play a crucial role in reducing the cost of downtime and improving system reliability. Consequently, machine condition monitoring plays an important role in maintaining operation stability and extending the period of usage for various machines. Machine condition monitoring through oil analysis is an effective method for assessing a machine's condition and providing early warnings regarding a machine's breakdown or failure. Among the three prevalent methods, the online analysis method is predominantly employed because this method incorporates oil sensors in real-time and has several advantages (such as prevention of human errors). Wear debris sensors are widely employed for implementing machine condition monitoring through oil sensors. Furthermore, various types of oil sensors are used in different machines and systems. Integrated oil sensors that can measure various oil attributes by incorporating a single sensor are becoming popular. By monitoring wear debris, machine condition monitoring using oil sensors is implemented for engines, automotive transmission, tanks, armored vehicles, and construction equipment. Additionally, such monitoring systems are incorporated in aircrafts such as passenger airplanes, fighter airplanes, and helicopters. Such monitoring systems are also employed in chemical plants and power plants for managing overall safety. Furthermore, widespread application of oil condition diagnosis requires the development of diagnostic programs.

• Smart Structures and Systems
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• 제13권6호
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• pp.993-1014
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• 2014

In civil engineering, revolving structures (RS) are a unique structural form applied in innovative architecture design. Such structures are able to revolve around themselves or along a certain track. However, few studies are dedicated to safety design or health monitoring of RS. In this paper, a wireless dynamic sensing system is developed for RS, and field tests toward a large revolving auditorium are conducted accordingly. At first, a wheel-rail problem is proposed: The internal force redistributes in RS, which is due to wheel-rail irregularity. Then the development of the sensing system for RS is presented. It includes system architecture, network organization, vibrating wire sensor (VWS) nodes and online remote control. To keep the sensor network identifiable during revolving, the addresses of sensor nodes are reassigned dynamically when RS position changes. At last, the system is mounted on a huge outdoor revolving auditorium. Considering the influence of the proposed problem, the RS of the auditorium has been designed conservatively. Two field tests are conducted via the sensing system. In the first test, 2000 people are invited to act as the live load. During the revolving process, data is collected from RS in three different load cases. The other test is the online monitoring for the auditorium during the official performances. In the end, the field-testing result verifies the existence of the wheel-rail problem. The result also indicates the dynamic sensing system is applicable and durable even while RS is rotating.

• 조명전기설비학회논문지
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• 제26권10호
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• pp.72-80
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• 2012

In general, electronic conveyor scales are installed in a relatively distributed manner on the crushed rock and sand production site. It is one of the time-consuming and difficult engineering works to monitor and control the plant operation status such as the management of measuring data, malfunction of belt conveyor, and fault of electronic conveyor scale. Therefore, to alleviate the inefficient problems and to monitor the operating plant in the online and remote control room, a remote calibration and real-time monitoring system, which is practically applied to the electronic conveyor scale system and verified by onsite experiment, is developed based on the LabVIEW.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2006년도 하계학술대회 논문집 Vol.7
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• pp.531-532
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• 2006

This paper presents the implementation of Real-time data acquisition system for dynamic characteristics of overhead contact wire in electric railway. The reconfigurable field-programmable gate array (FPGA) and LabVIEW graphical development tools have been used to Real-time monitoring system. The results from a field test show that the proposed technique and developed system can be practically applied to measure the assessment quantity or quantities on overhead contact lines for the online real-time process monitoring.

• Journal of Information Processing Systems
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• 제15권3호
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• pp.632-644
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• 2019

The remote monitoring and warning system for dangerous chemicals is designed with the concept of the Cyber-Physical System (CPS) in this paper. The real-time perception, dynamic control, and information service of major hazards chemicals are realized in this CPS system. The CPS system architecture, the physical layer and the applacation layer, are designed in this paper. The terminal node is mainly composed of the field collectors which complete the data acquisition of sensors and video in the physical layers, and the use of application layer makes CPS system safer and more reliable to monitor the hazardous chemicals. The cloud application layer completes the risk identification and the prediction of the major hazard sources. The early intelligent warning of the major dangerous chemicals is realized and the security risk images are given in the cloud application layer. With the CPS technology, the remote network of hazardous chemicals has been completed, and a major hazard monitoring and accident warning online system is formed. Through the experiment of the terminal node, it can be proved that the terminal node can complete the mass data collection and classify. With this experiment it can be obtained the CPS system is safe and effective. In order to verify feasible, the multi-risk warning based on CPS is simulated, and results show that the system solves the problem of hazardous chemicals enterprises safety management.

• 전기학회논문지
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• 제59권10호
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• pp.1741-1747
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• 2010

The development of overload management systems for distribution transformers offers new opportunities for improving the reliability of distribution systems. It allows network planners to optimize the system resource utilization and investment cost. Such an improvement in the flexibility of the distribution network is only possible if the operator has more accurate knowledge of the realtime conditions of distribution transformers. In this paper, we present an improved overload decision system for distribution transformers using realtime monitoring data. Our study can be categorized into two parts: (a) improvement in the criteria for judging the overload conditions of distribution transformers and (b) development of an overload evaluation system using realtime monitoring data. In order to determine the overload criteria, overload experiments are performed on sample transformers; the results of these experiments are used to define the relationship between the transformer overload and the increase in the top-oil temperature. To verify the accuracy of the experimental results, field tests are performed using specially manufactured transformers, the loads and top-oil temperatures of which can be measured. For arriving at online overload decisions, we propose methods whereby the measured load curve can be converted into an overload characteristic curve and the overload time can be calculated for any load condition. The developed system is able to evaluate the overload for individual distribution transformers and calculate the losses using realtime monitoring data.

• Journal of Electrical Engineering and Technology
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• 제11권6호
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• pp.1527-1534
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• 2016

Online voltage stability monitoring using real-time measurements is one of the most important tasks in a smart grid system to maintain the grid stability. Loading margin is a good indicator for assessing the voltage stability level. This paper presents an Extreme Learning Machine (ELM) approach for estimation of voltage stability level under credible contingencies using real-time measurements from Phasor Measurement Units (PMUs). PMUs enable a much higher data sampling rate and provide synchronized measurements of real-time phasors of voltages and currents. Depth First (DF) algorithm is used for optimally placing the PMUs. To make the ELM approach applicable for a large scale power system problem, Mutual information (MI)-based feature selection is proposed to achieve the dimensionality reduction. MI-based feature selection reduces the number of network input features which reduces the network training time and improves the generalization capability. Voltage magnitudes and phase angles received from PMUs are fed as inputs to the ELM model. IEEE 30-bus test system is considered for demonstrating the effectiveness of the proposed methodology for estimating the voltage stability level under various loading conditions considering single line contingencies. Simulation results validate the suitability of the technique for fast and accurate online voltage stability assessment using PMU data.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2007년도 하계학술대회 논문집 Vol.8
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• pp.525-526
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• 2007

Continuous on-line temperature monitoring provides the means to evaluate current condition of equipment and detect abnormality. It allows corrective measures to be taken to prevent upcoming failure. Continuous temperature monitoring and event recording provides information on the energized equipment's response to normal and emergency conditions. On-line temperature monitoring helps to coordinate equipment specifications and ratings, determine the real limits of the monitored equipment and optimize facility operations. Using wireless technique eliminates any need for special cables and wires with lower installation costs if compared to other types of online condition monitoring equipment. In addition, wireless temperature monitoring works well under difficult conditions in strategically important locations. Wireless technology for on-line condition monitoring of energized equipment is applicable both as standalone system and with an interface with power quality monitoring system.