• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 학술대회 논문집 전문대학교육위원
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• pp.76-79
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• 2001

Energy distribution function in $SiH_4$ has been analysed over the E/N range $0.5{\sim}300Td$ and Pressure value 0.5, 1.0, 2.5 Torr by a two-term approximation Boltzmann equation method and by a Monte Carlo simulation. The motion has been calculated to give swarm parameters for the electron drift velocity, diffusion coefficient, electron ionization, mean energy and the electron energy distribution function. The electron energy distribution function has been analysed in $SiH_4$ at E/N=30, 50Td for a case of the equilibrium region in the mean electron energy and respective set of electron collision cross sections.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1992년도 하계학술대회 논문집 A
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• pp.153-156
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• 1992

Transient stability analysis of Korea Electric power Corporation(KEPCO) system is conducted by time simulation method, and the method is robust and reliable. But, time simulation consumes enormous computing resources and engineering time, and it does not provide a measure of the degree of stability of the system. Therefore, this method does not apply to every changed condition appropriately and quickly in planning and operating. And Transient Energy Function (TEF) method whis can assess quickly and quantatively the degree of stability of the system and which judges the stability and the instability to analyse transient dynamic charater of the system by mutual changing kinetic energy and potential energy, is developed. TEF method analyses the first Swing transient stability of the system by using the thought that if after disturbance happening, the increase of all the rotator kinetic energy changes into the potential energy after diturbance clearing, the system is stable, otherwise the system is unstable. This paper represents the availabiIity of the TEF method by comparing with time simulation method on the two cases.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 제38회 하계학술대회
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• pp.465-466
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• 2007

Available transfer capability(ATC) quantifies the viable increase in real power transfer from one point to another in a power system. ATC calculation has predominantly focussed on steady-state viability. In many power systems, point-to-point transfer is not restricted by steady-state limits, but by undesirable dynamic behavior following large disturbance. In this paper, an energy function method for transient stability ATC computation is proposed, which utilizes a between the potential energy and energy function.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 추계학술대회 논문집 학회본부 A
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• pp.125-128
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• 2000

This paper presents an energy function which provides the direct relationships between the system stability and parameters of the exciter system. The energy function is derived from the energy conservation law by using the first motion integral. he time derivative does not absolutely satisfy the seminegativeness. However dE/dt usually has big negative value just after the fault clearing so that the energy is rapidly decreased. In this situation, the system state can be obviously confined in a stable region if the intial energy is less than the UEP energy. With these observation, two theorems are developed regarding the state confinement and asymptotic stability. Based on two theorems a new approximated direct energy method is developed to analyze the transient stability with the consideration of the exciter control effects. The proposed method has been tested for a single-machine-infinite bus system.

• 전자공학회논문지
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• 제53권8호
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• pp.19-27
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• 2016

IP 네트워크에서 에너지 절약을 위한 한 가지 방안으로 적응적 버퍼링 기법을 적용한 버스트 패킷 구성 및 그의 알고리즘에 대한 연구가 진행되어 왔다. 본 논문은 IP 네트워크의 ingress 라우터에서 버스트 스트림 패킷을 구성할 때, 에너지 절약을 위한 패킷 버퍼링 구간 결정 방법에 대해 검토한다. 특히 ingress 라우터의 입력 단에서 에너지 절약 효율을 높이기 위해 버스트 스트림 패킷을 만들 때 적응적 버퍼링 구간 및 구현 기법이 요구된다. 본 논문에서는 현재 버퍼링 구간은 과거 버퍼링 구간의 입력 트래픽을 기반으로 결정하는 최선의 적응적 역함수 버퍼링 결정 방식을 제안하고, 그의 에너지 절약과 지연 특성을 시뮬레이션을 통해 분석한다. 본 논문에서 적절한 역 지수함수를 이용하여 버스트 스트림 패킷 구성을 위한 버퍼링 구간을 결정하면, 에너지 절약 효과의 개선 및 평균 지연 변이를 감소시킬 수 있음을 나타낸다. 이 방법은 다른 방법에 비해 우수한 특성을 가지고 있음을 확인한다. 그리고 제안 방법은 다양한 입력 트래픽 유형에 민감하게 반응하지 않으며, 실용적인 방법임을 나타낸다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1997년도 춘계학술대회 논문집
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• pp.154-159
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• 1997

This paper describes the electron transport characteristic in SiH$_4$ gas calculated for range of E/N values from 0.5~300(Td) by the Monte Calro simulation and Boltzmann equation method using a set of electron collision cross sections determined by the authors and the values of electron swarm parameters are obtained for TOF method. The results gained that the value of an electron swarm parameter such as the electron drift velocity, the electron ionization coefficients longitudinal and transverse diffusion coefficients, characteristics energy agree with thee experimental and theoretical for a range of E/N. The electron energy distributions function were analysed in monosilane at EN : 30, 50(Td) for a case of equilibrium region in the mean electron energy. The validity of the results obtained has been confirmed by a TOF method.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 제39회 하계학술대회
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• pp.296-297
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• 2008

This paper proposed a methods to ATC calculation using energy function. In this paper, ATC was calculated as PTDF, LODF, RPF and Energy Function method and calculation results of each methods was compared. Contingency ranking method decided the overloading branches by PI-index. As a result, a study proved the fast and accurate ATC calculation method considering contingency suggested in this paper.

• 전기학회논문지
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• 제65권4호
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• pp.547-554
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• 2016

Analyze the customer daily load patterns, be used to determine the optimal charging and discharging schedule which can minimize the electrical charges through the battery energy storage system(BESS) installed in consumers is an object of this paper. BESS, which analyzes the load characteristics of customer and reduce the peak load, is essential for optimal charging and discharging scheduling to save electricity charges. This thesis proposes optimal charging and discharging scheduling method, using particle swarm optimization (PSO) and penalty function method, of BESS for reducing energy charge. Since PSO is a global optimization algorithm, best charging and discharging scheduling can be found effectively. In addition, penalty function method was combined with PSO in order to handle many constraint conditions. After analysing the load patterns of target BESS, PSO based on penalty function method was applied to get optimal charging and discharging schedule.

• Journal of Electrical Engineering and Technology
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• 제13권3호
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• pp.1110-1122
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• 2018

This paper proposes an alternative method to evaluate the effect of wind power to the power system stability with small disturbance. Alternatively, available techniques for stability analysis of a power system based on deterministic methods are less accurate for high penetration of wind power. Numerical simulations of random behaviors are computationally expensive. A stochastic stability index (SSI) is proposed for the power system stability evaluation based on the theory of stochastic stability and energy function, specifically the stochastic derivative of the relative well-defined energy function and the critical energy. The SSI is implemented on the modified nine-bus system including wind turbines under different conditions. A doubly-fed induction generator (DFIG) wind turbine is characterized and modeled using measured wind data from several sites in Thailand. Each of the obtained wind power data is analyzed. The wind power effect is modeled considering the aggregated effect of wind turbines. With the proposed method, the system behavior is properly predicted and the stability is quantitatively evaluated with less computational effort compared with conventional numerical simulation methods.

• Steel and Composite Structures
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• 제36권1호
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• pp.31-45
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• 2020

The purpose of this study is to develop an effective iterative two-stage method (ITSM) for structural damage identification of offshore platform structures. In each iteration, a new damage index, Modal Energy-Based Damage Index (MEBI), is proposed to help effectively locate the potential damage elements in the first stage. Then, in the second stage, the beetle antenna search (BAS) algorithm is used to estimate the damage severity of these elements. Compared with the well-known particle swarm optimization (PSO) algorithm and genetic algorithm (GA), this algorithm has lower computational cost. A modal energy based objective function for the optimization process is proposed. Using numerical and experimental data, the efficiency and accuracy of the ITSM are studied. The effects of measurement noise and spatial incompleteness of mode shape are both considered. All the obtained results show that under these influences, the ITSM can accurately identify the true location and severity of damage. The results also show that the objective function based on modal energy is most suitable for the ITSM compared with that based on flexibility and weighted natural frequency-mode shape.