• Proceedings of the KIEE Conference
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• 2002.11a
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• pp.102-105
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• 2002

ADSS(All Dielectirc Self-Supporting) cable installed under high voltage power cable line suffers a variety of environmental influence, rain, wind, snow fall, chemical pollution, salt fog and electrical stress. Its lifetime is required to be at least 20 years with this harsh weathering condition. The electrical stress under high voltage power line gives rise to dry band arcing and tracking, the severest damage, on the outer sheath of cable. Finally tracking might penetrate sheath and cause the break-down of ADSS cable. Tracking resistant sheath material, therefore, should be used to protect the core of ADSS from dry band arcing and to be sure long lifetime. In this work, we discuss various commercial tracking resistant material to investigate the way of track resistance and compare their mechanical, electrical, weathering and tracking properties through serial experiments. We found track resistant material is categorized into two main type : polyethylene with metal hydroxide and polyethylene with reduced carbon black. The Liquid contaminant, Inclined plane Tracking and Erosion test says the time to track of tracking resistant material with metal hydroxide has a little longer time to track in the high applied voltage than that with carbon black, but mechanical and weathering properties were inferior to.

• Journal of the Korean Solar Energy Society
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• v.28 no.3
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• pp.27-34
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• 2008

A series of outdoor tests were conducted on a fiber optic solar concentrator system for its performance on daylighting. The system is comprised of four main components - a parabolic dish reflector, a convex mirror, a homogenizer tube and an optical fiber cable. Results show that the system could be successfully applied for indoor lighting if some improvements are made for light transmiting (optical) cables. A maximum concentration ratio of 90 was observed delivering the illuminance of 4,800 lux at a distance of 1.2m from the diffuser for the outdoor illuminance of 102,100 lux.

• Journal of the Korean Society of Industry Convergence
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• v.23 no.6_2
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• pp.943-948
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• 2020

In this paper, we developed a fiber optic interferometer system based on frequency-swept laser. This frequency-swept laser with an external-cavity structure can generate a high coherent light with a linewidth of 132 kHz at 1552 nm. It also shows a superior swept linearity of R2 = 0.99995 under repetition rate of 200 kHz due to absence of mechanical moving parts in the laser cavity. By using a piezoelectric fiber optic stretcher, various vibration experiments were implemented, such as 0.5 to 2.0 kHz vibration signals with intervals of 0.5 kHz, with a sampling rate of 7 kHz. Real-time peak tracking can be successfully recovered according to the applied vibration frequency with high linearity of R2 = 0.99983.

• The Journal of the Korea institute of electronic communication sciences
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• v.9 no.4
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• pp.469-474
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• 2014

Installed on telephone poles laid scrambling to monitor the status of the communication lines, and cost information can provid eadditional information tools to develop systems to support on-site monitoring. Aerial support for a maintenance monitoring module to apply an embedded system, and information processing applications manufactured. In this study, a comprehensive plan in accordance with the government's aerial maintenance work to prevent accidents spread support for the device to immediately take advantage of big cities and aerial maintenance business, Construction worker accused of bias and aims to improve efficiency of maintenance puts.

• Smart Structures and Systems
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• v.18 no.6
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• pp.1203-1215
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• 2016

When strain sensing cables are under long-term stress and cyclic loading, creep may occur in the jacket material and each layer of the cable structure may slide relative to other layers, causing fatigue in the cables. This study proposes a device for testing the fatigue characteristics of three types of cables operating under different conditions to establish a decay model for observing the patterns of strain decay. The fatigue characteristics of cables encased in polyurethane (PU), GFRP-reinforced, and wire rope-reinforced jackets were compared. The findings are outlined as follows. The cable strain decayed exponentially, and the decay process involved quick decay, slow decay, and stabilization stages. Moreover, the strain decay increased with the initial strain and tensile frequency. The shorter the unstrained period was, the more similar the initial strain levels of the strain decay curves were to the stabilized strain levels of the first cyclic elongation. As the unstrained period increased, the initial strain levels of the strain decay curves approached those of the first cyclic elongation. The tested sensing cables differed in the amount and rate of strain decay. The wire rope-reinforced cable exhibited the smallest amount and rate of decay, whereas the GFRP-reinforced cable demonstrated the largest.

• Journal of the Korean Institute of Telematics and Electronics
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• v.27 no.11
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• pp.119-125
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• 1990

This paper describes fiber optic voltage sensor using EOM-BSO (Electro-Optic Modulator-Bismuth Silicon Oxcide). Transceiver has an electical/optical converter and an optical/electrical converter which consist of light emitting diode, PIN-PD, and electronic circuits. Multimode fiber cable of $100/140{\mu}m$ core/clad diameter is used for connecting the transceiver to fiber cable and fiber optic voltage sensor. Before our experiments, by applying the Maxwell equations and wave equations, We derive matrix equation on wave propagation in the BSO single crystal. And also we derive optimal equation on intensity modulation arising through an analyzer. According to experi-mental results, fiber optic voltage sensor has maximum $2.5{\%}$ error within the applied AC voltage of 800V. As the applied voltage increases, saturation values of voltage sensor also increase. This phenomenon is caused by optical rotatory power of BSO single crystal. And temperature dependence of sensitivity for fiber optical rotatory power of BSO single crystal. And temperature dependence of sensitivity for fiber optic voltage sensor in the temperature range from$-20^{\circ}C\to\60^{\circ}C$ are measured within ${\pm}0.6{\%}$. And frequency characteristics of the voltage sensor has good frequency characteristics from DC to 100kHz.

• Proceedings of the KIEE Conference
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• 1996.07b
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• pp.883-886
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• 1996

Instead of point-to-point hard wiring between substation yard equipments and SCADA RTU(Remote Terminal Unit), fibre optic cable will be used in the portion between Local Units and Central Unit in the future KEPCO 765kV substation. The connections between substation yard equipments and nearby Local Unit remain the same hard wiring. The new fibre optic system will provide security especially during ground faults and is immune to electrical noise. A prototype system will be manufactured and installed in the existing 154kV Yeosan Substation by the end of July this year and operated for one year. By incorporating the operation experiences acquired in the system, an improved system will be commercially applied to 765kV Shin-An-Seong Substation where 345kV GIS will be installed initially and act as the switching station in the year 1998. The system is composed of one Central Unit and several Local Units. The Central Unit is composed of two workstation level computers, one is in operation and the other backup, and a Communication Control Unit. The Local Unit uses the existing SCADA RTU technology and takes the form of a distributed one. Between the Communication Control Unit and Local Units, the fibre optic system with star-coupler is used.

• The Journal of Korea Robotics Society
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• v.12 no.1
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• pp.26-32
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• 2017

Previous shape sensors including bend sensors and optic fiber based sensors are widely used in various applications including goniometer and surgical robots. But theses sensors have large nonlinearity, limited in the range of sensing curvature, and sometimes are expensive. This study suggests a new concept of bend sensor using cable-conduit which consists of the outer sheath and the inner wire. The outer sheath is made of helical coil whose length of the central line changes as the sheath bends. This length change of the central line can be measured with the length change of the inner cable. The modeling and the experimental results show that the output signal of the proposed sensor is linearly related with the bend angle of the sheath with root mean square error of 5.3% of $450^{\circ}$ sensing range. Also the polynomial calibration of the sensor can decrease the root mean square error to 2.1% of the full sensing range.

• Proceedings of the IEEK Conference
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• 2004.08c
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• pp.876-879
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• 2004

The buried fiber optic cable as a distributed intrusion sensor for detecting and locating intruders along the long perimeters is proposed. Phase changes resulting from either the pressure of the intruder on the ground immediately above the buried fiber or from seismic disturbances in the vicinity are sensed by a phase-sensitive optical time-domain reflectometer. Light pulses from a Er:fiber cw laser with a narrow, <3kHz-range, spectral width and a frequency drift of < 1 MHz/min are injected into one end of the fiber, and the backscattered light from the fiber is monitored with a photodetector. Results of preliminary studies, measurement of phase changes produced by pressure and seismic disturbances in buried fiber optic cables and simulation of ${\varphi}-OTDR$ response over long fiber paths, to establish the feasibility of the concept are described. The field experiments indicate adequate phase changes, more than 1t-rad, are produced by intruders on foot and vehicle for burial depths in the 0.2 m to 1 m range in sand, clay and fine gravel soils. The simulations predict a range of 10 km with 35 m range resolution and 30 km with 90 m range resolution. This technology could in a cost-effective manner provide enhanced perimeter security.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.96-99
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• 2005

Fiber optic connector, ferrule, is a device to connect and align fiber optics cable on fiber-optic communication system. In this paper, Structural analysis was performed to analyze bed and frame structure of co-axial grinding machine. Deformation and modal analysis for natural frequency was performed using ANSYS Designspace program to analyze structural characteristics. New improved model of bed and frame structure was proposed based on initial basic model.