• Structural Engineering and Mechanics
• /
• v.88 no.6
• /
• pp.569-581
• /
• 2023

This paper introduces a system to detect and diagnose anomalies in pumped storage hydropower plants. We collect data from various types of sensors, including those monitoring temperature, vibration, and power. The data are classified according to the operation modes (pump and turbine operation modes) and normalized to remove the influence of the external environment. To detect anomalies and diagnose their types, we adopt a multivariate normal distribution analysis by learning the distribution of the normal data. The feasibility of the proposed system is evaluated using actual monitoring data of a pumped storage hydropower plant. The proposed system can be used to implement condition monitoring systems for other plants through modifications.

• Journal of Electrical Engineering and Technology
• /
• v.8 no.5
• /
• pp.1212-1220
• /
• 2013

In general, for a large power system like DC distribution system for buildings, several power converters are modularized for parallel operation. However, in parallel operation, inconsistency of parameters in each module causes circulating current in the whole system. Circulating current is directly related to loss, and, therefore, it is most important for the safety of the power system to supply the suitable current to each module. This paper proposes a control method to reduce circulating current caused during parallel operation. Accordingly, the validity of parallel operation system including response characteristics and normal state was verified by simulation and experiment result.

• Proceedings of the KSR Conference
• /
• 2004.06a
• /
• pp.522-527
• /
• 2004

Nowadays, becoming wide area is going on over Seoul Metropolitan area. But urban railway, very important traffic facilities, is operated in normal operating position and it gives cause to week the function of commuting long distance. This paper is focus on studying the feasibility of rapid operation system in Seoul Metropolitan area through comparing the present state of urban railway in Seoul Metropolitan area with a case of the advanced facilities in developed country. And we develop rapid operation system in general aspect through only consideration of operation planning without improvement of facilities. Also, we come up with new concept of rapid operation system through investigation of limits of the preceding researches

• The Bulletin of The Korean Astronomical Society
• /
• v.37 no.2
• /
• pp.195.1-195.1
• /
• 2012

Korea Aerospace Research Institute has developed an earth observation satellite whose primary mission objective is to provide high resolution electro optical earth images for Geographical Information Systems (GIS) establishment and the applications for environmental, agriculture and ocean monitoring. It was successfully launched into its mission orbit by using a commercial launch vehicle on 18th of May, 2012. This paper describes a series of launch activity at the launch site including its transportation to the launch site. Before conducting the launch site operation, satellite operation plane was prepared. Combining the satellite operation plan and launch vehicle activities, an integrated launch site operation plan and schedule have been drawn up. After arrival of the spacecraft at the launch site, post-ship check out has been conducted. And then it was fuel loaded and integrated with launch vehicle hardware. After completion of final electrical check out, count down procedure was executed. on 18th of May, it was launched into the space and was separated from the launch vehicle as planned. About 3 months of early operation and calibration/validation, now the satellite is conducting its normal mission.

• Journal of the Korean Institute of Telematics and Electronics C
• /
• v.34C no.9
• /
• pp.53-60
• /
• 1997

In this paper, an efficient BILBO(named EBILBO) is proposed for batch testing application when a BIST (built-in self test) circuit is implemented on ASIC. In a large and complex circuit, the proposed algorithm of batch testing has one pin-count that can easily control 4 test modes in the normal speed of circuit operation. For the implementation of the BIST cifcuit, the test patern needed is generated by PRTPG(pseudo-random test pattern generator) and the ouput is observed by proposed algorithm is easily modified, such as the modelling of test pattern genration, signature EBILBO area and performance of the implemented BIST are evaluated using ISCAS89 benchmark circuits. As a resutl, in a circuit above 600 gates, it is confirmed that test patterns are genrated flexibly about 500K as EBILBO area is 59%, and the range of fault coverage is from 88.3% to 100%. And the optimized operation frequency of EBILBO designed and the area are 50MHz and 150K respectively. On the BIST circit of the proposed batch testing, the test mode of EBILBO is able to execute as realtime that has te number of s$\^$+/n$\^$+/(2s/2p-1) clocks simultaneously with the normal mode of circuit operation. Also the proposed algorithm is made of the library with VHDL coding thus, it will be widely applied to DFT (design for testability) that satisfies the design and test field.

• Journal of the Korean Institute of Navigation
• /
• v.25 no.1
• /
• pp.33-44
• /
• 2001

Tankers have somewhat different shapes in construction and working condition compared with normal merchant ship. If an accident occurs, normal merchant ship's damages will mostly be confined to ship and cargo, but those of tankers will result in oil spills and catastrophic loss beyond our imagination. So, first we must understand risk factors, pre-loss control and post-loss control, legal regulations about its indemnification and marine insurance for oil tanker operation. When unexpected accidents happen, despite pre-loss control, it is possible to cover those kinds of losses by insurance. To control these losses, however, it is important to establish compensation for oil pollution and arrange for oil pollution preventing system. In spite of these oil pollution preventing systems, we have rarely seen that pollution from oil tankers could be solved. So this paper was studied more fundamental and overall control measures for the risk management of oil tanker operation.

• Proceedings of the Korean Radioactive Waste Society Conference
• /
• 2003.11a
• /
• pp.621-626
• /
• 2003

A DUPIC nuclear fuel is a newly developed fuel for CANDU reactors based on the concept of refabrication of spent PWR fuel by a dry process. Because a spent PWR fuel, a highly radioactive material, is used as a starting material, the experimental verification of DUPIC nuclear fuel fabrication requires an appropriate facility which should satisfy engineering requirements and guarantees safe operation. DUPIC nuclear fuel development team modified M6 hot-cell in IMEF to construct the dedicated facility(DFDF) for tile experiment. The experiment with spent PWR fuel have been conducted since January of 2000. Environmental effects of DFDF normal operation have been investigated when DUPIC nuclear fuel is fabricated with the maximum capacity of 50kg U/yr. The analysis results of the radiological safety of DFDF facility have shown that both national regulation limit and IMEF design criteria are satisfied.

• Journal of Drive and Control
• /
• v.15 no.2
• /
• pp.32-37
• /
• 2018

The power plants use turbine output control devices to supply or shut off steam to high pressure and low-pressure steam turbines connected to generators. This turbine output control device is driven by a hydraulic servo actuator. The gas flows into the hydraulic servo actuator during periodic inspection or normal operation, and the resulting adiabatic compression of the gas raises the internal temperature of the actuator to $500^{\circ}C$. This temperature increase causes the seals to burn and show wear and tear, resulting in failure. In this study, an air vent valve was installed to allow gas inside the hydraulic servo actuator to flow large quantities of air at the beginning of the operation and after the periodic inspection. Gas was passed through for only minute flow during normal operation of the power plant. By applying the air vent valve, it improves the reliability of the hydraulic servo actuator by discharge the gas appropriately to improve the life of the seal.

• Proceedings of the KIEE Conference
• /
• 2003.07a
• /
• pp.342-344
• /
• 2003

This paper describes the correction of overcurrent protective relaying set value in distribution networks interconnected with wind farm by dedicated line. The wind farm composed of wind turbine generators is one of the great energy sources; however, it would be also highly possible that the current in the point of common coupling is influenced by the output power of wind farm. So, the overcurrent relay applied in distribution feeders might generate trip signal for normal operation. In order to prevent the mal-operation of overcurrent relay, it is necessary to correct the relay's setting value according to the output power of end farm. This paper presents the influence of wind farm on the overcurrent relaying set value in distribution feeders for cases of fault as well as normal operation and proposes the basic strategy for correction of overcurrent relaying set value.

• Proceedings of the KOR-BRONCHOESO Conference
• /
• 1993.05a
• /
• pp.77-77
• /
• 1993

Laryngeal web is formed from various causes, and it is a scar tissue covered with epithelium on both sides. The purpose of the laryngeal web surgery is to cover the vocal cords with healthy epithelium and to achieve the normal or near normal function of respiration and phonation. Until now, a lot of surgical procedures were introduced, but have some merits and disadvantages. Recently authors tried this new surgical technique on 6 patients using the suspension laryngomicroscope under the intubation general anesthesia, which was to suture the upper and lower edges of the severed web. This new approach has several advantages; 1) familiar instruments and visual field 2) no unnecessary surgical trauma beyond the operation field 3) one stage operation 4) shorter operation time 5) no serious complications 6) short hospitalization, etc.