• 한국전자파학회논문지
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• 제19권2호
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• pp.237-243
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• 2008

본 논문에서는 무한히 넓은 백 플레인의 사각형 개구를 관통하는 길이가 다른 평행 2선 전송 선로에 대하여 백 플레인의 존재가 전송 선로에 미치는 영향을 검토하였다. 이론 해석에는 FDTD법을 사용하였으며, 길이가 다른 구조를 가지게 하는 부가 선로의 길이와 전송 선로의 간격 변화에 따른 반사 손실 및 삽입 손실 특성을 계산하여 백 플레인이 전송 선로에 미치는 영향을 고찰하였다. 그 결과, 전송 선로의 간격이 좁은 경우에는 부하 측의 전송 선로가 안테나처럼 동작하여 삽입 이득 특성이 나타나고, 부가 선로의 길이가 길어지면 백 플레인에 의한 삽입 손실 특성이 현저히 나타남을 확인할 수 있었다. 반사 손실을 측정하고 수치 계산 결과와 비교하여 이론 해석의 타당성도 확인하였다.

• 대한전기학회논문지:전력기술부문A
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• 제51권4호
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• pp.183-187
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• 2002

The efficient and rational transmission tariff structure is one of the crucial factors in creation of fair and competitive electricity markets. Transmission charge can be largely categorized into the line usage charge, system reliability charge, access charge and others. Any transmission tariff should be able to reflect these cost components reasonably. This paper suggests an approach amenable to allocating the transmission reliability costs reasonably with reflection of line sensitivity and line outage rate.

• 전기학회논문지
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• 제66권1호
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• pp.7-15
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• 2017

Ambient Adjusted line Rating(AAR) method for overhead transmission lines considering Risk Tolerance(RT) was proposed in this paper. AAR is suitable for system operators to plan their operation strategy and maintenance schedule because this can be designed as a seasonal line rating. Several candidate transmission lines are chosen to apply the proposed method in the paper. As a result, it is shown that system reliability was significantly enhanced through maximizing transfer capability, solving the system constraints.

• Journal of electromagnetic engineering and science
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• 제9권2호
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• pp.85-97
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• 2009

As operating frequency is raised and as more integration with active and passive elements is required, it becomes difficult to fabricate more than 120 ${\Omega}$ characteristic impedance of a mierostrip line. To solve this problem, an equivalent high impedance transmission-line section is suggested, which consists mainly of a pair of coupled-line sections with two shorts. However, it becomes a transmission-line section only when its electrical length is fixed and its coupling power is more than half. To have transmission-line characteristics(perfect matching), independently of coupling power and electrical length, two identical open stubs are added and conventional design equations of evenand odd-mode impedances are modified, based on the fact that the modified design equations have the linear combinations of conventional ones. The high impedance transmission-line section is a passive component and therefore should be perfectly matched, at least at a design center frequency. For this, two different solutions are derived for the added open stub and two types of high impedance transmission-line sections with 160 ${\Omega}$ characteristic impedance are simulated as the electrical lengths of the coupled-line sections are varied. The simulation results show that the determination of the available bandwidth location depends on which solution is chosen. As an application, branch-line hybrids with very weak coupling power are investigated, depending on where an isolated port is located, and two types of branch-line hybrids are derived for each case. To verify the derived branch-line hybrids, a microstrip branch-line hybrid with -15 dB coupling power, composed of two 90$^{\circ}$ and two 270$^{\circ}$ transmission-line sections, is fabricated on a substrate of ${\varepsilon}_r$= 3.4 and h=0.76 mm and measured. In this case, 276.7 ${\Omega}$ characteristic impedance is fabricated using the suggested high impedance transmission-line sections. The measured coupling power is -14.5 dB, isolation and matching is almost perfect at a design center frequency of 2 GHz, showing good agreement with the prediction.

• 한국전자파학회논문지
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• 제23권7호
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• pp.774-783
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• 2012

본 논문에서는 주기적인 요철 모양의 구조를 이용하여 인접해 있는 선로 간의 누화(crosstalk) 감소 효과를 갖는 전송 선로를 제안한다. 요철 모양의 전송 선로는 인접한 선로 간의 유도성 커플링과 용량성 커플링의 크기를 동일하게 조절이 가능하다. 따라서 유도성과 용량성의 커플링이 서로 상쇄되기 때문에 누화 감소 효과를 갖는다. 요철 모양의 전송 선로는 비유전율이 3.38이며, 두께가 0.508 mm인 RO4003 기판 위에 설계하였다. 전산모의 실험 결과, 일반적인 전송 선로와 주기 간격이 A=1 mm인 요철 모양 전송 선로의 far-end 누화는 30 GHz까지 각각 최대 -3.6 dB와 -22 dB 값을 가진다. 측정 결과, 일반적인 전송 선로와 A=1 mm인 요철 모양 전송 선로의 far-end 누화는 30 GHz까지 각각 최대 -6.3 dB와 -20.5 dB 값을 가진다.

• Earthquakes and Structures
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• 제15권6호
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• pp.583-593
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• 2018

Seismic performance is particularly important for life-line structures, especially for long-span transmission tower line system subjected to multi-component ground motions. However, the influence of multi-component seismic loads and the coupling effect between supporting towers and transmission lines are not taken into consideration in the current seismic design specifications. In this research, shake table tests are conducted to investigate the performance of long-span transmission tower-line system under multi-component seismic excitations. For reproducing the genuine structural responses, the reduced-scale experimental model of the prototype is designed and constructed based on the Buckingham's theorem. And three commonly used seismic records are selected as the input ground motions according to the site soil condition of supporting towers. In order to compare the experimental results, the dynamic responses of transmission tower-line system subjected to single-component and two-component ground motions are also studied using shake table tests. Furthermore, an empirical model is proposed to evaluate the acceleration and member stress responses of transmission tower-line system subjected to multi-component ground motions. The results demonstrate that the ground motions with multi-components can amplify the dynamic response of transmission tower-line system, and transmission lines have a significant influence on the structural response and should not be neglected in seismic analysis. The experimental results can provide a reference for the seismic design and analysis of long-span transmission tower-line system subjected to multi-component ground motions.

• Structural Engineering and Mechanics
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• 제6권7호
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• pp.773-784
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• 1998

To assess the collapse risk of transmission line structures subject to natural hazards, it is important to identify what hazard may cause the structural collapse. In Australia and many other countries, a large proportion of failures of transmission line structures are caused by severe thunderstorms. Because the wind loads generated by thunderstorms are not only random but time-variant as well, a time-dependent structural reliability approach for the risk assessment of transmission line structures is essential. However, a lack of appropriate stochastic models for thunderstorm winds usually makes this kind of analysis impossible. The intention of the paper is to propose a stochastic model that could realistically and accurately simulate wind loading due to severe thunderstorms. With the proposed thunderstorm model, the collapse risk of transmission line structures under severe thunderstorms is assessed numerically based on the computed failure probability of the structure.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2004년도 추계학술대회
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• pp.731-736
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• 2004

In this study, a linearized model of pneumatic cylinder position control system including transmission line is proposed. The transmission line using compressible fluid has a nonlinear transfer characteristics because that the frequency response of it is changed by the flowing state of the fluid. But, when the pressure difference between both sides of transmission line is low, the effect of resonance characteristics of it under high frequency range can be neglected because of the friction force and low pass characteristics of the position control system. Therefore, the transmission line can be modeled by second order transfer function and the natural frequency, damping ratio and gain are changed by the diameter and length of it. The effectiveness of the proposed model is proved by comparison of simulation results using proposed model with experimental results and simulation results using conventional model.

• 유공압시스템학회논문집
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• 제8권3호
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• pp.8-13
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• 2011

In the present study, a robust controller has been designed to control force for a pneumatic driving system considering the effect of a transmission line. Transfer characteristics of pneumatic transmission line should be changed according to the velocity of the air going through the transmission line. The designed controller is composed of two parts. The one is a feedback controller, which is composed of a stabilizing filter, a compensating filter of modelling error and a nominal model of the force control system, to compensate the influence of transmission line and improve the feedback characteristics of the control system, and, the other is a feedforward controller to achieve the control performance. Control results with the designed controller show that the robustness and performance of the control system are improved compared to the control results with a fixed gain controller.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2014년도 추계학술대회 논문집
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• pp.518-522
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• 2014

This paper is concerned with the dynamic modeling of transmission line undergoing galloping vibrations. To this end, the kinetic and potential energies of a uniform wire vibrating in space are derived. The equations of motion suitable for numerical simulations are derived using the assumed mode method and Lagrange equation. The resulting equations of motion are expressed in matrix form. To cope with bundled transmission line, the spacer was modelled by a spring element. As a numerical example, a two-wire transmission line combined by spacers was considered. Natural vibration characteristics show that the in-plane vibrations of the transmission line appeared in low frequency range, which may lead to galloping.