• 전기의세계
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• 제30권12호
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• pp.817-821
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• 1981

A simple scheme using the single equivalent machine representation, equivalent loss reprsentation and direct hydro-MW representation are applied to economic dispatch for practical applications. A,simple approach to calculation of incremental transmission losses is proposed from the fast decoupled load flow algorithm. This program is presently being tested on KECO system.

• Tribology and Lubricants
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• 제17권4호
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• pp.297-306
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• 2001

Under the condition of variable density and specific heat, maximum pressure, maximum temperature, bearing load, friction and side leakage in high-speed journal bearing operation are examined within some degree of Journal misalignment. The results are compared with the calculation results under the conditions of constant density and specific heat, and variable density and constant specific heat. It is found that the condition of variable density and specific heat play important roles in determining friction and load of Journal bearing at high speed operation.

• Journal of Electrical Engineering and Technology
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• 제12권5호
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• pp.1743-1753
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• 2017

Since there are multiple random variables in the probabilistic load flow (PLF) calculation of distribution system containing distributed generation (DG) and electric vehicle charging load (EVCL), a Monte Carlo method based on composite sampling method is put forward according to the existing simple random sampling Monte Carlo simulation method (SRS-MCSM) to perform probabilistic assessment analysis of voltage quality of distribution system containing DG and EVCL. This method considers not only the randomness of wind speed and light intensity as well as the uncertainty of basic load and EVCL, but also other stochastic disturbances, such as the failure rate of the transmission line. According to the different characteristics of random factors, different sampling methods are applied. Simulation results on IEEE9 bus system and IEEE34 bus system demonstrates the validity, accuracy, rapidity and practicability of the proposed method. In contrast to the SRS-MCSM, the proposed method is of higher computational efficiency and better simulation accuracy. The variation of nodal voltages for distribution system before and after connecting DG and EVCL is compared and analyzed, especially the voltage fluctuation of the grid-connected point of DG and EVCL.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 하계학술대회 논문집 A
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• pp.289-291
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• 2000

In a competitive electricity power market, the price of electricity changes instantly, that of conventional market is predetermined and hardly changes. In such a new environment, customers' behaviors change instantly according to the changing electricity prices. If we develop a electricity load model that well describes the behavior of electricity consumers, we can utilize that model in forecasting the amount of future load, solving the load flow problem and finding the weak point of the system. In this paper new electricity model that considers the price of electricity and power factor of the load is presented. While conventional load model, which is demand function of electricity, uses the price of real and reactive power as the independent variable of the demand function. this new load model uses price of real power and penalty factor according to the power factor for the calculation of amount of electricity demand.

• 전기학회논문지
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• 제65권3호
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• pp.397-403
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• 2016

Generally, an electrical distribution configuration is a radial system with one-way current in a distribution management system (DMS). All feeders in a DMS have tie-switches to make radial system. Sometimes, DMS should change a tie-switch for operation. In that case, the tie-switch has to be closed first; then a switch is opened as another tie-switch in order to prevent blackout for customers. At the moment when the tie-switch is closed, distribution system is operated in a loop state, not radial. Before the loop operation, DMS operator has to check any expected events for stable distribution system operation; and the most important event is a mis-operation of a protection relay. In addition, DMS operator should check voltage profile violation but a calculation method of section voltages had not been used. Thus, this paper proposes a calculation method of section voltages at a loop operation in a DMS. The proposed calculation algorithm is verified by Matlap Simulink.

• 조명전기설비학회논문지
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• 제21권2호
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• pp.86-93
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• 2007

본 논문은 가용송전용량(ATC)를 계산하기 위한 두 가지 빠른 계산 기법을 제안한다. 이 방법들은 선로의 열적용량한계(Thermal ATC)와 전압 안정도한계(Voltage ATC)를 제약조건으로 ATC를 계산한다. 먼저 선로의 열적용량을 고려한 방법에서는 모선의 전력 변화에 대한 선로의 조류 감도인 PTDF와 n-1 상정사고를 고려한 LODF를 이용하였으며, 전압안정도를 고려한 방법에서는 2모선 등가 시스템을 이용하여 최대 전력을 구하는 방법을 이용하였다. 제안된 방법은 IEEE 30모선 계통에 적용하였으며 그 결과를 다른 방법과 비교하여 제안된 방법의 타당성을 입증하였다.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2009년도 공동학술대회
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• pp.287-288
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• 2009

분산발전원의 위치 변경에 따른 전력조류 및 송전전력 손실 평가를 통하여 도시차원에 적합한 발전원 설치점 선정 기법의 개발이 시급하다. 본 연구에서는 전력손실을 고려하여, 분산전원이 주변의 모선 및 선로에 미치는 영향을 최소화 할 수 있도록, 분산전원의 설치지점을 선정하는 방안을 제안한다.

• 소성∙가공
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• 제4권3호
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• pp.204-213
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• 1995

A finite element program is developed to analyze the flow phenomena in SMC compression molding as a viscoplastic model. The calculation of temperature distribution is also carried out by uncoupling the thermal analysis from the flow analysis. SMC molding processes with a flat plate substructure and the one with a T-shaped rib are considered in numerical simulation. The numerical results provide deformed shapes, temperature distribution in a SMC charge, and the forming load. The simulation of compression molding of a flat plate with a T-shaped rib requires a remeshing technique for the whole process.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1997년도 하계학술대회 논문집 D
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• pp.775-777
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• 1997

This paper presents an algorithm for the calculation of LSC(Load Supplying Capability) in composite power systems. LSC means the maximum load which the composite power system can supply under the constraints of interest and power flow equations. In this paper, Successive Linear Programming algorithm is used to calculate the LSC of composite power systems. This algorithm is applied to the Six-Bus system and IEEE RTS.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1997년도 추계학술대회 논문집 학회본부
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• pp.215-217
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• 1997

In many conventional analysis of voltage stability the effect of load characteristics is ignored. But in the real system the load is composed of various components. Therefore if the load composition could be modeled then it will plays an important role in the analysis of static voltage stability. And also, if the system loss generally imposed to slack bus in the conventional load flow calculation is redistributed to each generator the accuracy of static voltage stability analysis can be improved. This paper presents the effect of load composition in the analysis of system stability as well the loss redistribution algorithm. And this paper will compare the result of conventional method with that of the proposed method.