• Earthquakes and Structures
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• 제17권4호
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• pp.387-398
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• 2019

On the basis that ground motions may arrive at a structure from any horizontal direction and that different directions of seismic incidence would result in different structural dynamic responses, this paper focuses on orienting the crucial seismic incidence of transmission tower-line systems based on the wavelet energy method. A typical transmission tower-line system is chosen as the case study, and two finite element (FE) models are established in ABAQUS, with and without consideration of the interaction between the transmission towers and the transmission lines. The mode combination frequency is defined by considering the influence of the higher-order modes of the structure. Subsequently, wavelet transformation is performed to obtain the total effective energy input and the effective energy input rate corresponding to the mode combination frequency to further judge the critical angle of seismic incidence by comparing these two performance indexes under different seismic incidence angles. To validate this approach, finite element history analysis (FEHA) is imposed on both FE models to generate comparative data, and good agreement is found. The results demonstrate that the wavelet energy method can forecast the critical angle of seismic incidence of a transmission tower-line system with adequate accuracy, avoiding time-consuming and cumbersome computer analysis. The proposed approach can be used in future seismic design of transmission tower-line systems.

• 한국지능시스템학회논문지
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• 제20권6호
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• pp.831-836
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• 2010

실제 시스템 적용에 있어서, 수중음향 통신(underwater acoustic communication)에 기반한 이종 해양로봇의 협력제어(coordinated control)를 위한 경로 계획 및 추종(path planning and following) 시스템은 다음의 문제점을 가지고 있다. 즉, 수상 및 수중로봇은 기동 특성이 상이하며, 수중로봇은 더욱 효과적인 운용이 요구되며, 음파의 전달 손실(Transmission Loss : TL)로 통신 거리 제한을 가지며, 음파의 도플러 변형(Doppler distortion)으로 통신 오류를 갖는다. 나아가, 구조와 파라메터의 관점에 있어서 용이한 설계 절차를 요구한다. 이러한 문제들을 해결하기 위해서 시스템 모델링에 기초하여 진화 전략(Evolution Strategy : ES) 및 퍼지논리 제어기(Fuzzy Logic Controller : FLC)를 이용하는 지능형 경로 계획 및 추종 알고리즘을 제안하였다. 제안된 알고리즘의 성능을 검증하기 위해 수상로봇의 기동에 따른 수중로봇의 경로 계획 및 추종이 수행되었다. 시뮬레이션 결과는 제안된 알고리즘이 제기된 문제점들을 효과적으로 해결하고 있음을 보여준다.

• 대한전기학회논문지
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• 제38권8호
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• pp.585-592
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• 1989

This paper presents an efficient algorithm for the reactive planning of transmission network under normal operating conditions. The optimal operation of a power system is a prerequisite to obtain the optimal investment planning. The operation problem is decomposed into a P-optimization module and a Q-optimization module, but both modules use the same objective function of generation cost. In the investment problem, a new variable decomposition technique is adopted which can operate the operation and the investment variables. The optimization problem is solved by using the gradient projection method (GPM).

• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 제38회 하계학술대회
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• pp.485-486
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• 2007

In the deregulated power market, suppliers, consumers and transmission companies try to maximize their profits by economical behaviors. In particular, generating companies like to sell more electricity for the revenue. Their situations will lead to various power system planning as optimal solutions for each supplier. In this paper, fundamental approaches of optimal power system planning under market positions of generating company are presented. The profit-maximizing approaches are modeled mathematically. By this analysis, each optimal planning is proved in risk of cost and monetary risk will be the economical signal for participants.

• 전기학회논문지
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• 제56권3호
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• pp.481-490
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• 2007

WASP which is used to plan generation expansion has disadvantages that can't manage environmental factors and regional supply-demand planning. But with the effectuation of the United Nations Framework Convention on Climate Change (UNFCCC) and Kyoto Protocol, it is expected that reducing greenhouse gases affects power system in its long-term generation expansion planning. Therefore national countermeasures is needed. This paper formulates a mathematical model considering CO2 emission constraints and Emission Trading that will be enforced. This model is based on the MEFISET (Model for Economic Feasibility of Interstate Electrical Ties) which was made by Korea Energy Economics Institute and Hong-ik university and manages generation expansion planning. And this mathematical model is verified by studying a case system.

• 한국초전도저온공학회:학술대회논문집
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• 한국초전도저온공학회 2000년도 KIASC Conference 2000 / 2000년도 학술대회 논문집
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• pp.125-127
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• 2000

In this study, we performed long lange power transmission expansion planning for conceptual design of HTS power cable in Seoul area. Since the HTS power cable has the high power transmission density and low loss characteristics in comparison with conventional power cables, the HTS power cable is introduced between the downtown and the suburbs in the future system in order to verify the feasibility of the HTS power transmission cables technically and to encourage the research activity in the area.

• Journal of Electrical Engineering and Technology
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• 제7권5호
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• pp.698-704
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• 2012

This paper proposes a new methodology for evaluating the probabilistic reliability based grid expansion planning of composite power system including the Wind Turbine Generators. The proposed model includes capacity limitations and uncertainties of the generators and transmission lines. It proposes to handle the uncertainties of system elements (generators, lines, transformers and wind resources of WTG, etc.) by a Composite power system Equivalent Load Duration Curve (CMELDC)-based model considering wind turbine generators (WTG). The model is derived from a nodal equivalent load duration curve based on an effective nodal load model including WTGs. Several scenarios are used to choose the optimal solution among various scenarios featuring new candidate lines. The characteristics and effectiveness of this simulation model are illustrated by case study using Jeju power system in South Korea.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1993년도 하계학술대회 논문집 A
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• pp.67-69
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• 1993

The purpose of the facility investment planning for bulk power system is to appropriately configure the power system network to supply the load, which has the supply capability satisfying the probabilistically changing load on the desired reliability level. In order to achieve this purpose, this paper represents the reliability evaluation of the KEPCO's real system with using the MEXICO model, and builds the data base of the power system operation in order to effectively handle the computer model.

• 항공우주시스템공학회지
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• 제14권6호
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• pp.26-35
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• 2020

The national satellite operation network, which supports multiple satellites, was designated as a Critical Information Infrastructure (CII) in 2017. The network was designed independently from the control network and the information network to enhance physical security. Planning is underway to establish a bidirectional data interface between networks. The data transmission system allows data flow only to the physical layer and the data link layer; hence, only one file can be transferred at any one time. This means that when large amounts of data are being transmitted, no other data can be sent simultaneously in urgent situations. Thus, this paper discusses the design of flexible packets for the transmission of data between networks in an environment where physical security has been enhanced through network separation and based on this, presents a method for transmitting data effectively.

• Journal of Electrical Engineering and Technology
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• 제10권5호
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• pp.1921-1929
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• 2015

The smart substation is the heart of a transmission system, which is particularly emphasized as the most significant composition of smart grids in China. In order to assess the functionality performance of substation technologies, this paper presents methods used to identify the most promising solutions for smart substation design and to evaluate the technical levels of available technologies. The multi-index optimization model is presented to address the issue of smart substation planning. A mathematical model of the planning decision problem is established with multiple objectives consisting of economic, reliability, and green key indices, and many kinds of concerns including physical and environmentally friendly operations are formulated as a set of constraints. With respect to the assessment of the technical level regarding integration of advanced technologies into a substation, a modified grey whitenization weight function is adopted to structure a novel grey clustering method. The proposed grey clustering approach is used to overcome the difficulty of insufficient quantitative assessment capacity for traditional methods. The evaluation of technical effects provides the classification definition for the development phase and the maturity level of the smart substation. The effectiveness of the proposed approaches in planning decision-making and evaluation of construction efforts is demonstrated with case studies involving the actual smart substation projects of Wenchongkou substation in China Southern Power Grid (CSG) and Mengzi substation in State Grid Corporation of China (SGCC).