• 전기학회논문지P
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• 제63권3호
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• pp.131-137
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• 2014

It is expected that there will be delay of scheduled transmission network reinforcement and huge investment of renewable energy resources in Korea. As transmission capacity expansion delayed, supplying power to Seoul metropolitan area will not be increased as scheduled. In addition, uncertain renewable energy out of Seoul metropolitan area can cause transmission congestion in the future power system. These two combining effects will make the difference in locational marginal prices(LMP) and congestion costs increase. In that sense, this paper will analyze how much the congestion costs for Korea power system are incurred in the future power system. Most of previous approaches to analyze the congestion costs for electric power system are based on the optimal power flow model which cannot deal with hourly variation of power system. However, this study attempted to perform the analysis using market simulation model(M-Core) which has the capability of analyzing the hourly power generation cost and power transmission capacity, and market prices by region. As a result, we can estimate the congestion costs of future power system considering the uncertainty of renewable energy and transmission capacity.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 추계학술대회 논문집 전력기술부문
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• pp.129-131
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• 2006

KEPCO constructed the first 765kV 2 circuit transmission line in the world with its home grown technologies. Through this 765kV transmission system project, KEPCO accumulated experience and technologies related to the 765 kV power system. Based on the successful completion of the 765kV transmission project, KEPCO is conducting overseas business by using its abundant experience and know-how. In particular, KEPCO developed the training course for power system, called the ATT (Advanced Transmission Technology) training courses for overseas business, especially for developing countries. Therefore, KEPCO developed the "Transmission line design system for overseas projects". This system supports the calculation of wind pressure load, tower design, wire selection, insulation design, etc. by applying the meteorological data of foreign countries and design standards. And this system is applied to the training program so that the trainees can design the optimal transmission line for their own countries.

• Journal of Electrical Engineering and Technology
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• 제13권1호
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• pp.105-113
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• 2018

This paper proposes pre-analysis on planning of high-voltage direct current (HVDC) transmission system applied to Korea electric power grid. HVDC transmission system for interface lines has been considered as alternative solution for high-voltage AC transmission line in South Korea since constructing new high-voltage AC transmission lines is challenging due to political, environmental and social acceptance problems. However, the installation of HVDC transmission system as interface line in AC grid must be examined carefully. Thus, this paper suggests three scenarios to examine the influences of the installation of HVDC transmission system in AC grid. The power flow and contingency analyses are carried out for the proposed scenarios. Power reserves in metro area are also evaluated. And then the transient stability analysis focusing on special protection scheme (SPS) operations is analyzed when critical lines, which are HVDC lines or high voltage AC lines, are tripped. The latest generic model of HVDC system is considered for evaluating the impacts of the SPS operations for introducing HVDC system in the AC grid. The analyses of proposed scenarios are evaluated by electromechanical simulation.

• 한국정밀공학회지
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• 제15권10호
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• pp.120-127
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• 1998

In this study the dynamic characteristics of automatic transmission system due to the change of the planetary gear ratio is studied. To study the power flow and shift quality for power transmission the simulation program is developed using the modeling and analysis technique. The results from this study will be used in designing the basic structure of automatic transmission using planetary gear system.

• Earthquakes and Structures
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• 제17권6호
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• pp.635-647
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• 2019

Tests and theoretical studies for seismic responses of a transmission tower-line system under coupled horizontal and tilt (CHT) ground motion were conducted. The method of obtaining the tilt component from seismic motion was based on comparisons from the Fourier spectrum of uncorrected seismic waves. The collected data were then applied in testing and theoretical analysis. Taking an actual transmission tower-line system as the prototype, shaking table tests of the scale model of a single transmission tower and towers-line systems under horizontal, tilt, and CHT ground motions were carried out. Dynamic equations under CHT ground motion were also derived. The additional P-∆ effect caused by tilt motion was considered as an equivalent horizontal lateral force, and it was added into the equations as the excitation. Test results were compared with the theoretical analysis and indicated some useful conclusions. First, the shaking table test results are consistent with the theoretical analysis from improved dynamic equations and proved its correctness. Second, the tilt component of ground motion has great influence on the seismic response of the transmission tower-line system, and the additional P-∆effect caused by the foundation tilt, not only increases the seismic response of the transmission tower-line system, but also leads to a remarkable asymmetric displacement effect. Third, for the tower-line system, transmission lines under ground motion weaken the horizontal displacement and acceleration responses of transmission towers. This weakening effect of transmission lines to the main structure, however, will be decreased with consideration of tilt component.

• 대한전기학회논문지:전력기술부문A
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• 제53권1호
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• pp.43-55
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• 2004

This paper presents a study on evaluating the reliability indices considering a transmission system. Because successful operation of electric power under the deregulated electricity market depends on transmission system reliability management, quantity evaluation of transmission system reliability is very important. This paper introduces features and operation modes of the Transmission Reliability Evaluation for Large-Scale Systems(TRELSS) Version 6.0, a commercial program made in EPRI, and TranRel-I V3.2, a educational program made in GSNU(GyeongSang National University) for assessing reliability indices of composite power system. The packages access not only bulk but also bus indices for reliability evaluation of composite powers system. The practicality, effectiveness and future works of this methodology are illustrated by demonstrations of two case studies of modified IEEE 25 buses reliability test system using TRELSS and TranRel-I and a brief case study for the KEPCO size system using TranRel-II made in GSNU.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제55권3호
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• pp.182-188
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• 2006

Contactless power system is base on power transmission by magnetic force. The transformer loss is large because it separated with the gap. Also the system has unstable factor, since the parameters in the secondary can vary with the system movement. This paper proposes light train power transmission system using contactless transformer with multiple primary winding. To increase the system efficiency and to obtain the stable power transmission to the dynamic load, a resonant inverter is adopted. The proposed system was verified by the simulation using Spice and Maxwell. The designed contactless power transmission system is implemented for 5[kW] class and experimental results are discussed.

• 반도체디스플레이기술학회지
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• 제18권1호
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• pp.21-24
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• 2019

In this paper, 5.8GHz 25W microwave wireless power transmission system was developed. The transmission system is composed of a signal generator, a 1W drive amplifier, a 25W power amplifier, and a circularly polarized transmission antenna. The receiving system was fabricated with an integrated receiver that combines a circularly polarized receiving antenna, a pass band filter, and an RF-DC converter. And a multi-integrated receiver had twelve parts, including an integrated receiver. Under the conditions, voltage and current were measured for the system at 5cm intervals from a minimum distance of 5cm to a maximum distance of 80cm. The power was calculated for the system. The results of the system are shown in tables and graphs. The power decreases with distance, but the power does not drop sharply due to a multi-integrated receiver.

• 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.

• 한국정보통신학회논문지
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• 제11권7호
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• pp.1247-1253
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• 2007

본 논문에서는 통신해양기상위성 센서 데이터 송수신 시스템의 요구 시스템 위상 잡음 스펙트럼 분포도를 제안하였다. 위상 잡음 영향을 최소화하기 위한 해석된 수신 설계 파라미터를 기반으로 센서 측정 신호인 raw, LRIT 및 HRIT 데이터 전송에 적합한 위상 잡음 특성을 제시하였다. 제안된 위상 잡음 특성은 전송 채널상에서 발생하는 주파수 신호 자원의 위상 잡음 영향을 최소화하며, 서비스 단말에 양호한 전송 성능을 제공한다. 또한 제안된 위상 잡음 스펙트럼은 센서 데이터 송수신 시스템의 주파수 발생원의 신호 특성으로 설계할 수 있도록 한다.