• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.9 no.5
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• pp.687-697
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• 1998

In spite of increasing public concern about the human exposure to electric and magnetic fields(EMFs), there is little information about the EMF levels in the vicinity of power facilities and of home appliances. To provide such information, a nationwide survey for EMFs near overhead transmission lines has been conducted. The median values of the electric fields and magnetic fields of 153 transmission lines were 0.47 kV/m and 11.6 mG, respectively. The maximum values were 3.16 kV/m and 125 mG. These were low values in comparison with any EMF guidelines or standards of advanced contries. Measurements of the magnetic fields of typical home appliances and daily human exposure records have been also conducted. These magnetic field values were comparable to those of the transmission lines.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.264_265
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• 2009

최근 국내에서 가스절연송전선(GIL : Gas Insulated Transmission Line)의 실계통 도입을 위하여 345kV급 GIL의 개발 및 적용을 위한 연구 및 검토가 수행되고 있다. 가공선로의 일부구간을 GIL로 대치하는 데 있어서, 변전소측이 원거리일 경우에는 변전소 내부의 차단기나 단로기 등 개폐 써지에 의한 과전압의 영향은 감쇄효과로 인하여 그다지 크지 않지만, 현재 설치 예정선로와 같이 변전소 측과의 거리가 약 2.6[km]로 짧을 경우 차단기 동작에 의한 개폐써지의 영향을 무시할 수 없게 된다. 따라서 본 논문에서는 GIL 시스템이 가공송전선로와 연계된 경우 근접한 변전소단에서 개폐를 가정하였을 때, GIL 시스템과 가공송전선로에서 발생할 수 있는 개폐과전압에 대하여 과도해석 프로그램인 EMTP를 이용하여 검토하였다.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.1297_1298
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• 2009

According to previous report, aged sleeves for old transmission lines have various defect such as biased installation or corrosion of steel sleeve. These defects occupied almost 50 percent of investigated aged sleeves. These defects can cause serious accidents such as rapid increasing of sag or falling out of overhead conductor from sleeves. Moreover, the defects have been limited power capacity of transmission line. This paper study on thermal behavior of ACSR 480Rail conductor and sleeve with various defect model. The detailed results were presented in the text.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.58 no.4
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• pp.447-450
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• 2009

In order to protect conductors from oscillations or vibrations due to winds, spacer dampers are installed on overhead transmission lines. Generally the spacer damper clamp can move slightly according to oscillation directions, namely in longitudinal, vertical & horizontal directions. This is for reducing fatigue phenomena of the conductor. But the high longitudinal- displacement of the clamp raises a doubt for its necessity. Then this paper carried out oscillation tests by using 4 bundle test lines, to know the relation between longitudinal displacement and oscillation. and suggests design necessity of the longitudinal articulation part for spacer damper clamps.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.11a
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• pp.461-461
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• 2008

According to previous report, aged sleeves for old transmission lines have various defect such as biased installation or corrosion of steel sleeve. These defects occupied almost 50 percent of investigated aged sleeves. The defects have been limited power capacity of transmission line. And it can cause serious problems such as rapid increasing of sag or falling out of overhead conductor from sleeve. This paper study on thermal behavior of sleeve with various defect model. The detailed results were presented in the text.

• Proceedings of the KIEE Conference
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• 2001.11b
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• pp.395-398
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• 2001

Recently, the increasing need for internet and the activation of hiring business of communication line makes the demand for OPGW cable which can construct the optical communication network in the basis of existing overhead power transmission line. Especially, the demand is focused on the high fiber count OPGW due to high capacity transmission. In step with the trend toward high fiber count cable we have developed the Stainless Steel Loose Tube type OPGW within which have 144core firstly in KOREA. This paper describes the cable design and manufacturing process which gives the stable operation in very severe conditions and the long-term reliability test results conducted in according to dominant specification IEEE Std. 1138-1194.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.109-110
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• 2007

Most transmission lines pass through mountainous terrain and deep valleys, to avoid populated areas. Accordingly, the impact of climate changes, environmental conditions and system expansion have caused an increase in transmission line system fault rates. KEPCO has developed and applied phase-spacers to reduce contact faults between phases. Contact between phases represented 9% of total line faults before the devices were installed. Phase-spacers have reduced faults by up to 3.4% since the phase-spacers were installed in 2005. Also, recently developed devices provide additional economic benefits as they cost about a third of the price as similar devices introduced in foreign countries. Phase-spacers are an effective way to prevent phase contact accidents by maintaining physical space between phases. These spacers will be implemented in areas where contacts are likely to occur. They are expected to reduce accident rates and improve power quality.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.395_396
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• 2009

This paper handles with effect of electromagnetic force on the cables by fault current accompanied by accident of underground transmission cable. Even though underground transmission cable is an essential transmission method to supply stable power for downtown and population center, interaction of electromagnetic force from fault current is very large comparing to overhead transmission line due to restricted installation space such as tunnel, etc. and close consideration is required for it. This paper describes the effect of electromagnetic force through results of three phase short-circuit test and electromagnetic force analysis using theoretical calculations and electrical evaluation test after three phase short-circuit test, which will be utilized as basic materials for improvement and development of cleat, hanger, etc. to reduce and release effect of electromagnetic force in the future.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38B no.2
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• pp.130-139
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• 2013

In recent, the communication networks of wind power farm are becoming crucial technologies for monitoring and controlling the large-scale offshore wind power farm. In this paper, EPON based communication network architectures are proposed in order to combat the problems of conventional Ethernet based communication network such as delay, data processing overhead and the fairness of data transmission among turbines in offshore wind power farm. The proposed architecture constructs the point to multi-point network by using OLT and ONUs installed in central control center and wind turbines respectively. The EPON based communication network architecture has low cost, high reliability, and fair transmission capability. To evaluate the performance of proposed architectures, the wind power farm based on IEC 61850 is modelled by using OPNET The simulation results are analyzed and compared with conventional Ethernet based communication network in terms of the overhead, delay and fairness of data transmission.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.49 no.12
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• pp.595-601
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• 2000

This paper describes the improvement method of distance relaying algorithm for the underground transmission cables. Distance relaying algorithms have been mainly developing to protect the overhead transmission lines than the underground cables. If the cable systems are directly protected using distance relaying algorithm developed for overhead line without any improvement, there will be really occurred many misoperation in cable systems, because the cable systems consist of the conductor, the sheath, several grounding method, cable cover protection units(CCPUs), and grounding wire. Accordingly, the complicated phenomena are occurred, if there is a fault in cable systems. Therefore, to develope a correct distance relaying algorithm, such cable characteristics should be taken into account. This paper presents the process to improve distance relaying algorithm which is now used. REal cable system was selected to establish modeling in EMTP and ATP Draw. It was discovered through the detailed simulation during the fault that the large error existed between impedance measured at the relay point and real impedance is due to the resistance of grounding wire in each grounding method. And also compensation factor obtained by the simulation is proposed in this paper. It is proved that the factor proposed can fairly improve the accuracy of impedance at the relay point. It is evaluated that the protective ability will be really much improved, if the algorithm proposed in this paper is applied for cable systems of utility.