• 대한전기학회논문지:전력기술부문A
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• 제48권11호
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• pp.1410-1416
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• 1999

This paper aims at investigating the operating-mode characteristics of two-module Thyristor Controlled Series Compensator (TCSC) as an equivalent of the multi-module TCSC in a simple three-phase power transmission system. The load flow program is developed to analyze the steady-state characteristics of two-module TCSC system and to find the thyristor firing angles for the required real power flow. The stability calculation program is developed with Poincare mapping theory. Simulation studies of the TCSC power transmission system using EMTP are performed to evaluate the transient characteristics of two-module TCSC as a real power flow controller and to rpove the results of the load flow calculation and the stability analysis. In the process of the study, the operating-mode characteristics of two-module TCSC are evaluated and compared to those of single-module TCSC.

• 한국인터넷방송통신학회논문지
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• 제19권5호
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• pp.175-180
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• 2019

새로운 고유치 문제에 기초한 모드 전송선로 이론 (Modal Transmission-Line Theory: MTLT))을 이용하여 blazed 격자 구조형 방향성 결합기 (B-GADC)의 광학 특성과 채널사이의 전력전달을 자세하게 분석하였다. 설계한 B-GADC의 결함효율을 분석하기 위하여 격자주기와 파장에 따라 변하는 quasi-TE 모드와 quasi-TM 모드의 분산곡선을 수치 해석하였으며, blazing 특성이 GADC의 결합효율에 미치는 영향을 분석하기 위하여 대칭형, 톱니형 그리고 비대칭형 blazed 격자구조를 설계하고 평가하였다. 수치해석 결과, blazed 격자구조가 대칭형에서 비대칭형으로 변함에 따라 최대 전력전송을 위한 최소 간격 조건을 만족하는 격자주기는 줄어들었으며 결합길이는 반대로 늘어나는 것을 확인하였다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제15권6호
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• pp.2282-2303
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• 2021

To solve the problems of heavy computing load and system transmission pressure in energy internet (EI), we establish a three-tier cloud-edge integrated EI network based on a cloud-edge collaborative computing to achieve the tradeoff between energy consumption and the system delay. A joint optimization problem for resource allocation and task offloading in the threetier cloud-edge integrated EI network is formulated to minimize the total system cost under the constraints of the task scheduling binary variables of each sensor node, the maximum uplink transmit power of each sensor node, the limited computation capability of the sensor node and the maximum computation resource of each edge server, which is a Mixed Integer Non-linear Programming (MINLP) problem. To solve the problem, we propose a joint task offloading and resource allocation algorithm (JTOARA), which is decomposed into three subproblems including the uplink transmission power allocation sub-problem, the computation resource allocation sub-problem, and the offloading scheme selection subproblem. Then, the power allocation of each sensor node is achieved by bisection search algorithm, which has a fast convergence. While the computation resource allocation is derived by line optimization method and convex optimization theory. Finally, to achieve the optimal task offloading, we propose a cloud-edge collaborative computation offloading schemes based on game theory and prove the existence of Nash Equilibrium. The simulation results demonstrate that our proposed algorithm can improve output performance as comparing with the conventional algorithms, and its performance is close to the that of the enumerative algorithm.

• Journal of Electrical Engineering and Technology
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• 제12권2호
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• pp.576-585
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• 2017

Dynamic thermal rating (DTR) of overhead transmission lines can provide a significant increase in transmission capacity compared to the static thermal rating. However, the DTR are usually estimated by the traditional thermal model of overhead conductor that is highly dependent on the solar, wind speed and wind direction data. Consequently, the estimated DTR would be unreliable and the safety of transmission lines would be reduced when the solar and wind sensors are out of function. To address this issue, this study proposed a novel thermal model of overhead conductor based on the thermal-electric analogy theory and Markov chain. Using this thermal model, the random variation of conductor temperature can be simulated with any specific current level and ambient temperature, even if the solar and wind sensors are out of function or uninstalled. On this basis, an estimation method was proposed to determine the DTR in the form of probability. The laboratory experiments prove that the proposed method can estimate the DTR reliably without measured solar and wind data.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 하계학술대회 논문집 A
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• pp.195-198
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• 2004

In recent, the Importance and necessity of some studies on reliability evaluation of grid comes from the recent black-out accidents occurred in the world. The quantity evaluation of transmission system reliability is very important under competitive electricity environment. Accurate probabilistic reliability evaluation depends on assessment of forced outage rate of elements, generators, transmission lines. This paper describes basic theory of relationship between outage rates and reliability evaluation for assessing FOR(forced outage rate) of elements of power system. In case study, FORs assessed and supplied from Canada Electricity Association is introduced and FORs assessed from using actual historical data from 1997 to 2002 for transmission lines of KEPCO system.

• 한국전자파학회논문지
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• 제18권4호
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• pp.448-454
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• 2007

본 논문에서는 CR(Cognitive Radio)의 가장 적합한 인공지능 기술로 주목받고 있는 게임 이론을 전력 제어 방식에 적용해 CDMA 시스템 기반의 사용효율과 효용에 대한 성능 평가 결과를 제시하였다. 사용자와 네트워크 동시 최적화를 위한 효용함수식을 정의하였으며 모의실험을 통해 FOM(Figure of Merit)과 형평성(Fairness)에서 기존의 폐루프 전력 제어 방식보다 월등한 성능을 입증하였다. 또한 게임 이론을 적용한 전력 제어 방식은 통신 환경을 인지하고 연산하여 적합한 최적의 서비스를 제공하는 CR의 여러 분야에 확장 적용 가능함을 제시하였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 하계학술대회 논문집 D
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• pp.2404-2406
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• 2000

Chua's circuit is a simple electronic network which exhibits a variety of bifurcation and attractors. The circuit consists of two capacitors, an inductor, a linear resistor, and a nonlinear resistor. In this paper, a transmitter and a receiver using two identical Chua's circuits are proposed and synchronizations of a T or ${\pi}$ type power line are investigated. Since the synchronization of the power line system is impossible by coupled synchronization, theory having both the drive-response and the coupled synchronization is proposed. As a result, the chaos synchronization has delay characteristics in the power line transmission system caused by the line parameters L and C

• 한국전자파학회:학술대회논문집
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• 한국전자파학회 2003년도 종합학술발표회 논문집 Vol.13 No.1
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• pp.126-130
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• 2003

The optical power transfer of TM modes in grating-assisted directional couplers (GADCs) with three-guiding channels is rigorously evaluated by defining a novel coupling efficiency amenable to the rigorous analytical solutions of modal transmission-line theory (MTLT). The results reveal that the incident power is sensitively partitioned through three output channels in terms of such grating parameters as the period, the duty cycle, and wavelength.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 제36회 하계학술대회 논문집 A
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• pp.609-611
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• 2005

In this study electromagnetic wave fields under power lines arc derived by dipole antenna theory and electromagnetic fields under 3 phase power lines with horizontal and vertical configuration are formulated. The calculation results by those formulas were consistent with the results of reference. The formulas were applied to 345[kV] and 765[kV] transmission lines constructed in our country.

• KIEE International Transactions on Power Engineering
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• 제2A권3호
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• pp.121-128
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• 2002

This study proposes a new method for transmission system expansion planning using fuzzy integer programming. It presents stepwise cost characteristics analysis which is a practical condition of an actual system. A branch and bound method which includes the network flow method and the maximum flow - minimum cut set theorem has been used in order to carry out the stepwise cost characteristics analysis. Uncertainties of the permissibility of the construction cost and the lenient reserve rate and load forecasting of expansion planning have been included and also processed using the fuzzy set theory in this study. In order to carry out the latter analysis, the solving procedure is illustrated in detail by the branch and bound method which includes the network flow method and maximum flow-minimum cut set theorem. Finally, case studies on the 21- bus test system show that the algorithm proposed is efficiently applicable to the practical expansion planning of transmission systems in the future.