• Proceedings of the KIEE Conference
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• 1987.11a
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• pp.143-146
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• 1987

Fiber optics provide a solution to the problems at interference, capacity and reliability in communication. Approximately 20 kilometera of a six-fiber, multimode, longwave($1.3{\mu}m$), graded index silica glass fiber optic cable was helically wrapped around a phase conductor at a Korea Electric Power Corporation(KEPCO) 154KV transmission line. This paper presents an economic comparison of several fiber optic cable installation alternative and discusses the characteristics at the helically wrapped fiber cable, as well as the entire installation, including high voltage phase-to-ground (PTG) end termination, and splicing. The fiber link was installed for the field trial and practical use with overhead composite optical fiber cable which installation performed a few years earlier some other location and is intended to accommodate not only telephone but also supervisory Control and Data Acquisition(SCADA), protective relaying, and telemetry functions.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2009.10a
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• pp.163-167
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• 2009

Although the domestic electric power consumption of lighting have shared 20${\sim}$30 % of the national electric power consumption, the spread of lighting control system which can reduce the electric power consumption have been insignificant. The government have set the demonstration project and given the incentive to promote the spread of lighting control system since 2008. The M&V (Measurement and Verification) methodology for lighting control system have not been set yet in our country, but the direct measurement was suggested in US. The direct measurement methodology can increase the accuracy of measurement, but it cost much money to burden a customer. This study have suggested a new M&V methodology which cost low and is simple relatively. I had measured the amount of electric consumption through both the direct measurement and the new M&V program computation, and have analyzed the deviation. The amount of electric consumption measured by the new M&V program computation have agreed with one by the direct measurement within the error range of the instrumentation in case of lab scale test, and the 4${\sim}$8 % deviation have existed in case of field evaluation.

• Journal of the Speleological Society of Korea
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• no.76
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• pp.37-42
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• 2006

The Dielectric Barrier Discharge (DBD) is a nonequilibrium gas discharge that is generated in the space between two electrodes, which are separated by an insulating dielectric layer. The dielectric layer can be put on either of the two electrodes or be inserted in the space between two electrodes. If an AC or pulse high voltage is applied to the electrodes that is operated at applied frequency from 50Hz to several MHz and applied voltages from a few to a few tens of kilovolts rms, the breakdown can occur in working gas, resulting in large numbers of micro-discharges across the gap, the gas discharge is the so called DBD. Compared with most other means for nonequilibrium discharges, the main advantage of the DBD is that active species for chemical reaction can be produced at low temperature and atmospheric pressure without the vacuum set up, it also presents many unique physical and chemical process including light, heat, sound and electricity. This has led to a number of important applications such as ozone synthesizing, UV lamp house, CO2 lasers, et al. In recent years, due to its potential applications in plasma chemistry, semiconductor etching, pollution control, nanometer material and large area flat plasma display panels, DBD has received intensive attention from many researchers and is becoming a hot topic in the field of non-thermal plasma.

• Proceedings of the KIEE Conference
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• 1998.07b
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• pp.792-794
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• 1998

As the modern industrial processes become more complex, it is getting more difficult to model and control the processes. The PID controller has been widely used in power plant process control since its structure is simple and familiar to the field engineer. This paper describes the application of the PID controller developed DCS system in power plant.

• International Journal of Highway Engineering
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• v.15 no.2
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• pp.19-27
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• 2013

PURPOSES : This study aims to investigate the snow-melt effects of an underground electric heater's snow-melt system via a field performance test, for evaluating the suitability of the system for use on a concrete pavement. The study also investigates the effectiveness of dynamic measures for clearing snow after snowfall events. METHODS : In order to check the field applicability, in November 2010, specimens were prepared from materials used for constructing concrete pavements, and underground electric heating meshes (HOT-mesh) were buried at depths of 50 mm and 100 mm at the site of the Incheon International Airport Construction Research Institute. Further, an automatic heating control system, including a motion sensor and pavement-temperature-controlled sensor, were installed at the site; the former sensor was intended for determining snow-melt effects of the heating control system for different snowfall intensities. Pavement snow-melt effects on snowy days from December 2010 to January 2011 were examined by managing the electric heating meshes and the heating control system. In addition, data on pavement temperature changes resulting from the use of the heating meshes and heating control system and on the dependence of the correlation between the outdoor air temperature and the time taken for the required temperature rise on the depth of the heating meshes were collected and analyzed. RESULTS : The effects of the heating control system's preheat temperature and the hot meshes buried at depths of 50 mm and 100 mm on the melting of snow for snowfalls of different intensities have been verified. From the study of the time taken for the specimen's surface temperature to increase from the preheat temperature ($0^{\circ}C$) to the reference temperature ($5{\sim}8^{\circ}C$) for different snowfall intensities, the correlation between the burial depth and outdoor air temperature has been determined to be as follows: Time=15.10+1.141Depth-6.465Temp CONCLUSIONS : The following measures are suggested. For the effective use of the electric heating mesh, it should be located under a slab it may be put to practical use by positioning it under a slab. From the management aspect, the heating control system should be adjusted according to weather conditions, that is, the snowfall intensity.

• Proceedings of the KIEE Conference
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• 1993.07b
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• pp.1193-1196
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• 1993

Electrical properties of $C_{22}$-Quinolium(TCNQ) Langmuir-Blodgett(LB) films are reported depending on a type of applied voltage on a type of applied voltage and temperature. A conductivity was identified to be anisotropic with a ratio of ${\sigma}||/{\sigma}{\bot}{\simeq}10^7$ at room temperature. The I-V characteristics along the film surface direction show an ohmic behavior up to a few hundred volts. But the I-V characteristics in the vertical direction display an ohmic behavior for low-electric field, and a nonohmic behavior for high-electric field. This nonohmic behavior has already been interpreted as a conduction mechanism of space-charge limited current and Schottky effect near the electric-field strengh of $10^6$ V/cm. When the electric field exceeds further, there is anormalous phenomia similiar to breakdown. From the study of I-V characteristics with the application of step or pulse voltage, we have found that the breakdown voltage shifts to higher one as the step or pulse interval becomes shorter. These results indicate that the breakdown is due to both electrical and thermal effect. To see the infulence of temperature, current was measured as function of temperature with several bias voltages, which are lower than that of breakdown. It shows that the current increases about 3 orders of magnitude near $60{\sim}70^{circ}C$, and remains constant for a while up to $140^{\circ}C$ and then suddenly drops. Arahidic acid was used to cmpare with $C_{22}$-Quinolium(TCNQ) LB films.

• Proceedings of the KIEE Conference
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• 1998.07e
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• pp.1629-1631
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• 1998

Crosslinked polyethylene (XLPE) insulated cables are now widely used all over the world for extra-high voltage underground transmission systems. Prefabricated type (compression type) joint has developed in order to shorten the assembly time and lower the possibility of contamination at site by many companies in the world. For outdoor termination, to control the electric field distribution as uniform as possible, especially for the use of extra-high voltage system. much of products are adopting the oil-impregnated condensor cone type instead of electric field control element which uses the permitivity of it only (not capacitance). For Gas-immersed termination, dimension of outer insulation bushing was determined by IEC Publication 859. The highest voltage of underground power cable system is 345kV now, in Korea. We have much of experiences of the development of prefabricated type accessories for CV cable systems (154kV, 161kV, 230kV level). So it was possible to inspect the proto type of accessories for 345kV CV cable system and seems that the need time for the development of products is reduced.

• Journal of Environmental Health Sciences
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• v.26 no.3
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• pp.55-60
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• 2000

Wire codes, introduced by Wertheimer and Leeper, are interesting largely because several case-control studies have reported associations between them and certain types of cancers, including childhood leukemia. This paper is concerned with the reliability of wire codes as a surrogate for residential electric and magnetic field, divided into four categories based on the electrical wiring within 40m of homes. To examine the correlation between spot measurements and wire codes, EMF was measured by using HI-3604 and classified by wire codes. The correlation between long-transformed RMS of magnetic field and wire codes was 0.81. But the correlation between log-transformed RMS of electric field and wire codes was 0.27. The results led us to determine a four category from of the Wertheimer and Leeper code that 1) may be useful in domestic epidemiological studies and 2) is not suitable for electric field exposure. Thus, the critical point of exposure assessment in residential magnetic field is to classify a wire code precisely.

• Proceedings of the KIEE Conference
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• 2001.07b
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• pp.1169-1171
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• 2001

Synchronous reluctance motors(SynRM) for the application such as an electric vehicle, compressor drives of air conditioner and machine tool spindle drives require a wide field-weakening speed range. In order to improve the efficiency performance in such applications, this paper has examined the loss and the efficiency characteristics of SynRM mainly in the field-weakening speed region over the base speed. The control strategy in order to offer a efficiency optimization operation is shown and the copper and iron losses driven the equivalent circuit model of the machine is minimized. The usefulness of the proposed efficiency optimization control is verified through the SynRM durve system.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2005.05a
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• pp.180-183
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• 2005

The engine mount of vehicle systems is role of support engine mass and isolate noise and vibration from engine disturbance forces. One of attractive candidates to achieve this goai is to utilize a semi-active ER engine mount. By applying this, we can effectively control damping force and hence the noise and vibration by just controlling the intensity of electric field. However, control performance of the engine mount may be very sensitive to temperature variation during engine operation. In this work, we Investigate dynamic performances of ER engine mount with respect to the temperature variation. In order to undertake this, a flow-mode type of ER engine mount is designed and manufactured. Displacement transmissibility is experimentally and numerically evaluated as a function of the electric field. The ER engine mount is then incorporated with full-vehicle model in order to investigate vibration control performance. After formulating the governing equation of motion, a semi-active controller is designed. The controller is implemented through a hardware-in-the-loop simulation (HILS), and control responses such as acceleration level at various engine speeds are evaluated in the frequency and time domains.