• 대한전기학회:학술대회논문집
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• 대한전기학회 1996년도 하계학술대회 논문집 B
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• pp.905-907
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• 1996

Current design standard of substation grounding systems is primarily concerned with conventional outdoor substations. But in case of 154kV substations in the nation, almost all are indoor-type GIS substations. So there became to be something not proper for application of present design standard to indoor-type substations. In this paper, as a preliminary stage of drawing-up of the grounding system design standard which concerned with in-door-type substions, issues of current design standard are mentioned and directions of improvement are also presented.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1998년도 하계학술대회 논문집 C
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• pp.1235-1237
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• 1998

Spacer Dampers must be carefully designed and tested. Because it can protect conductors from conductor oscillations due to winds and electrical forces. If the spacer damper has any problems in itself, it may cause extensive damage to the transmission lines. This paper suggests a design method and considerations of spacer damper for bundled conductor transmission lines.

• 한국초전도저온공학회:학술대회논문집
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• 한국초전도저온공학회 1999년도 제1회 학술대회논문집(KIASC 1st conference 99)
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• pp.129-133
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• 1999

In recent years, there is a growing needs for large capacity underground power transmission lines with the increasing demand of electric power in the urban area, where various environmental limitations are imposed on the overhead transmission lines. But it is difficult to get the space for the underground power transmission cables because of complicated distributions of underground public facilties such as subway, water pipes, gas etc. As the superconducting power cables have the large power transmission capacity, the high power transmission capacity, the high power transmission density, and low loss characteristics in comparison with a conventional cable, it would be a solution to meet the increased power demand. In this paper, the results of the conceptual design and analysis of power system of HTS power transmission cable is described.

• KEPCO Journal on Electric Power and Energy
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• 제5권2호
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• pp.75-81
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• 2019

본 연구에서는 최근 정부에서 제시한 표준설계 응답스펙트럼을 이용하여 송전용량, 높이 및 구조타입 등 다양한 변수를 고려한 송전철탑 24기를 선정하여 내진성능평가를 수행하였다. 또한, 정부에서 요구한 내진기준 상향 시 철탑의 설계에 미치는 영향을 검토하기 위하여, 현 설계 풍하중 및 개정 지진하중에 의해 발생되는 응력 및 단면력의 크기를 비교해 보았다. 내진성능평가 결과 대상 철탑들은 0.31~0.91g의 내진성능을 보유하고 있는 것으로 나타나, 2,400년 재현주기의 내진특등급 수준을 만족하였으며 내진안전성을 확보하고 있는 것으로 나타났다. 또한, 철탑의 지진에 의한 단면력은 풍하중에 의한 값의 33~82.5%로 나타나, 상향된 내진기준에서도 설계 풍하중이 지진하중보다 지배적임을 확인하였다.

• Journal of electromagnetic engineering and science
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• 제14권2호
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• pp.54-60
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• 2014

A systematic design for asymmetric coupled-section Marchand baluns is presented. Asymmetrically coupled transmission lines in multilayer configuration are exploited for constructing Marchand baluns. Design equations for characteristic impedance and electrical length of asymmetrical coupled transmission lines are derived for establishing a systematic design procedure. Novel Marchand balun based on these design equations is composed of two identical asymmetrical coupled transmission lines. However, contrary to the general conventional design approach where ranges for characteristic impedances of coupled lines are ambiguously capitalized, values for characteristic impedance and length are explicitly expressed. Our approach is fundamentally different from the design method using coupling coefficients where solution for coupling coefficient is inherently restricted. To verify the proposed method, one design example is performed for wideband Marchand balun in multilayer configuration, and is fabricated for verifying the design procedure proposed. Maintaining the return loss more than 10 dB, the bandwidth is measured from 0.43 to 1.0 GHz, where $S_{21}$ and $S_{31}$ show better than -4 dB. The measured phase and amplitude imbalances illustrate 0.5 dB and ${\pm}5^{\circ}$, respectively.

• Journal of the Korean Wood Science and Technology
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• 제46권4호
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• pp.338-345
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• 2018

The sound insulation capacity of a barrier is indicated by its transmission loss. In this study, the sound transmission loss of a sound barrier filled with rice-straw particles was measured by the transfer function method and a laboratory measurement method. The results of the two measurements were compared. The transmission losses measured by the two methods were similar above a frequency of 500 Hz. The loss increased greatly upon the introduction of a plywood to the sound barrier. The results of this study are expected to be used to design sound barriers for roads.

• 전자공학회논문지A
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• 제32A권6호
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• pp.19-28
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• 1995

In this paper, measured iris transmission loss data and simulated data by using 3-dimension full-wave analysis S/W are presented and compared with Marcuvitz's theory. And by using measured iris data, dual-mode narrow-band channel filters can be successfully implemented. This paper shows that there is severe difference between the transmission loss of iris calculated by using Marcuvitz's equation to calculate iris dimension, if the length of slot iris is longer than .lambda./.pi., and in the long urn the response of channel filter is distorted. Experimental result shows that the characteristic response of implemented channel filter by using the iris transmission loss graph presented here matches well the design specfications. In conclusion, iris transmission loss measurement method will be very useful to design channel filter.

• International Journal of Precision Engineering and Manufacturing
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• 제9권1호
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• pp.7-11
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• 2008

A new continuously variable transmission (CVT) for electric bicycles was developed using a traction drive mechanism with inner and outer spherical rotors. This electric bicycle CVT permits three propulsion modes: human-power only, motor-power only, or a combination of motor power and human power. In addition, the electric bicycle CVT has high power efficiency, large torque capacity, improved drivability, and good packageability. A prototype was manufactured based on a conceptual design, a performance analysis, and a detailed design. This prototype has a rated power of 250 W and input motor speed of 20 rad/s for an overall speed ratio in the range 0.3-1.2. A bench test was conducted to measure the power transmission performance of the prototype.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2014년도 추계학술대회 논문집
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• pp.116-118
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• 2014

A shape optimization problem is formulated to optimally design aluminum sandwich panel, which is used for high speed railway vehicle. An aluminum volume used in the panel is selected as a design objective with constraints on the stiffness and the transmission loss value. The formulated shape optimization problem is solved for a well -selected initial shape. The stiffness and transmission loss value of the obtained optimal shape are compared with those of the previously-reported panel.

• 대한전기학회논문지:전력기술부문A
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• 제55권12호
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• pp.555-560
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• 2006

As it has been reported that more than 60% of transmission line faults occurs due to lightning strokes, lighting is one of concerned issues in electric power utility company. Most of transmission line is double circuit in Korea. Double circuit outages account for 33.7 percent of total lightning faults from 1996 to 2004. Even though transmission fault might be cleared shortly by protective system, it could deteriorate the power quality accompanied with sag or flicker. Moreover, double circuit fault may lead to more aggravated situation, for instance, blackout. To Protect transmission lines from lightning stroke, reduction of tower footing resistance, multiple ground wires and unbalanced insulation in double circuit lines have been adopted. In this paper, we would like to introduce insulation design standards for lightning protection of Korea Electric Power Corporation.