• Proceedings of the KIEE Conference
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• 2007.11b
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• pp.112-114
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• 2007

전력선에서 발생하는 자속으로 인해 주변 통신선이나 도체에 영향을 주는 유도장해는 특히 전력선의 지락사고 시 전력선에서 발생한 큰 자속이 주변 통신선 등에 쇄교하여 높은 전자유도 전압을 발생한다. 선로 정수를 계산하여 자체적으로 인덕턴스와 정전용량 계산이 가능한 EMTP를 통하여 154kV 전력선의 실측데이터를 바탕으로 1선 지락사고 시의 전력전송 등가모델을 구현하여 주변 통신선에 유도되는 전압을 시뮬레이션을 통해 자료를 얻는다. 이론적으로 알고 있는 유도장해를 실험을 통하여 확인함을 이 논문의 목표로 한다.

• Journal of Electrical Engineering and information Science
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• v.3 no.1
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• pp.45-50
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• 1998

This paper deals with some characteristics of a nondestructive eddy current detector to measure OPGW(Composite overhead ground wire with optical fiber) corrosion. This detector is designed to automatically run on OPGW and to continuously inspect the corrosion of the line. The impedance of the eddy current coil changing by any corrosion phenomenon of OPGW is analyzed. Several performances of the detector are described and experimental procedures and test results are also given. As a result, it is shown that the implemented detector can be measured some quantitative data for crack, broken wires or severe deteriorations in OPGW. This nondestructive test method would be applied to improve the reliability and efficiency of transmission line in service.

• Proceedings of the KIEE Conference
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• 1999.11d
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• pp.1034-1037
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• 1999

In this paper, we analyze the inductive interference in conductive material around power transmission line. To compute induced eddy currents as well as electromagnetic fields, finite element method(FEM) is used for numerical calculation. The characteristics of conductive material such as gas pipeline, overhead guide wires, conducting earth and so on are taken account of FEM analysis. This research also shows that mitigation wire reduces amount of eddy current in buried gas pipe line.

• Proceedings of the KIEE Conference
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• 2005.07b
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• pp.1035-1037
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• 2005

The analysis of magnetic fields(2-D) induced by line currents, such as Overhead Trolley Lines or Transmission Lines, is not so easy by using the standard Finite Element Method(FEM). Mesh generation is one of the most important processes in the standard FEM. Because, the current region is relatively small compared with whole region, and actually is a line without thickness, the mesh refinement around the source lines yields many demerits. A way of supplement such a defect, we proposed the coupling scheme of analytical solution and FEM. In this study, the analytical solution is adopted around the region of line currents and FE solution is a lied to the rest of source region. And the two types of solution are coupled at the artificial boundary. To verify the usefulness of proposed algorithm, simplified model with magnetic material in FE region is chosen and analyzed. The results are compared with those of standard FEM. And the errors between them can be reduced by increasing harmonic orders.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.363_364
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• 2009

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 presents countermeasures to reduce and release the effect of electromagnetic force with rope binding and installation of spacer and describes its efficacy through 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.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.21 no.11
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• pp.1036-1041
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• 2008

According to previous report, aged sleeves of old transmission line showed several defaulted installation patterns, which was biased or corrosive-fractured of steel sleeve installed cases. These defects can cause serious accidents such as rapid increasing of sag or falling out of overhead conductor from sleeves. Consequently, the defects lead to the major power outage. Corrosion of steel sleeve is a typical defect by aging of sleeves. And it occupied almost 25 percent of investigated aged sleeves. This paper studied thermal properties and tension for ACSR conductor in case of fractured steel sleeve model by corrosion. The temperature distribution within overhead conductor has a specific gradient. Thermal properties of splice connectors(sleeve and clamp) showed normal behavior. However, mechanical properties were worse than normal sleeves. The detailed results were presented in the text.

• Journal of Internet Computing and Services
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• v.7 no.6
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• pp.175-183
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• 2006

An ad-hoc network is a group of mobile nodes acting as routers. The of hoc node has a precondition of mobility, allowing path to be easily disconnected when transmitting data, thereby increasing network overhead. However, most of hoc routing protocols set up the path based only on the number of hops without considering other practical factors. Here we consider a path with the least substantial number of transmission (SNT) from source to destination based on reliabilities of links. This includes retransmissions due to unreliable links. In this paper, an efficient ad-hoc link reliability based routing (PU) protocol suitable for mobile ah-hoc network in terms of SNT, is proposed. The network overhead and data transmission delay ore reduced, by considering both ad-hoc link reliability and the number of hops. Our empirical performance evaluation comparing to AODV (8) shows that the enhancement is up to about 31% for SNT depending upon the mobility of nodes.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.55 no.3
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• pp.141-145
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• 2006

The line current problem(2-dimensional space : point source) is not easy to analyze the magnetic field using the standard finite element method(FEM), such as overhead trolley line or transmission line. To supplement such a defect this paper is proposed the coupling scheme of analytical solution and FEM. In analysis of the magnetic field using the standard FEM. If the current region is a relatively small compared to the whole region. Therefore the current region must be finely divided using a large number of elements. And the large number of elements increase the number of unknown variables and the use of computer memories. In this paper, an analytical solution is suggested to supplement this weak points. When source is line current and the part of interest is far from line current, the analytical solution can be coupling with FEM at the boundary. Analytical solution can be described by the multiplication of two functions. One is power function of radius, the other is a trigonometric function of angle in the cylindrical coordinate system. There are integral constants of two types which can be established by fourier series expansion. Also fourier series is represented as the factor to apply the continuity of the magnetic vector potential and magnetic field intensity with tangential component at the boundary. To verify the proposed algorithm, we chose simplified model existing magnetic material in FE region. The results are compared with standard FE solution. And it is good agreed by increasing harmonic order.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.48 no.6
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• pp.25-34
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• 2011

In this paper, In this paper, we propose a Cooperative Routing Protocol (CooRP) for supporting network convergence and transmission services efficiently in mobile ad-hoc wireless sensor networks with Rayleigh fading environments. The main contributions and features of this paper are as follows. First, the routing routes are decided on route stability based on entropy concepts using mobility of nodes within the direction guided line region to increase the operational lifetime of routes as well as reduce control overhead for route construction. Second, a cooperative data transmission strategy based on the constructed stable routing route is used to increase packet delivery ratio with advanced SNR. Third, a theoretical analysis for cooperative data transmission of the proposed CooRP with outage probability is presented. The performance evaluation of the proposed CooRP is performed via simulation using OPNET and analysis. The results of performance evaluation show that the proposed CooRP by using stable routing routes and cooperative transmission can increase packet delivery ratio efficiently.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.54 no.3
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• pp.127-131
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• 2005

Big fire such as mountain fire may cause the prevention of the functions of the overhead cables and insulators, which may affect the operation of the transmission lines. In the worst case, this kind of disaster may have a huge effect on the whole industry of a country. However, the study on the effect of the mountain fire on the transmission line is very rare. Therefore, in order to understand the effect of the mountain fire on the polymeric insulator for transmission lines, the author observed the deformation of the sheds of the polymeric insulators and the change of the discs of the porcelain insulators under fire, varying the ignition time using the artificial ignition testing equipment which simulates the mountain fire, and investigated the electrical and mechanical characteristics of the insulators after the ignition test. For the test, the miniature insulators made of polymeric material and porcelain have been utilized. As the result, the following conclusions were obtained. First, the porcelain insulator was degraded in electrical characteristics when the insulator was subjected to the fire for approximately 5 minutes; whereas, the polymeric insulator was not degraded though there were some damage on its sheds. Second, after 20 minute exposure to the fire, the polymeric insulator lost a lot of parts of sheds, but the electrical characteristics was lowered by around $20\%$, but the porcelain insulators were electrically degraded by more than $80\%$.