• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 하계학술대회 논문집 C
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• pp.1990-1992
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• 2000

Isolated phase bus is, as a special bus which allows large current from a generator to main transformer, composed of main conductor, enclosure and auxiliary equipments such as insulating bellows, bus elbows, support insulator, etc. To develop this kind of high power devices, it is required to secure the technique of selection of conducting and insulating materials, basic arrangement skills, and analysis on eddy current which causes temperature increase in enclosures. By the way, these techniques are based on the analysis of electromagnetic phenomena for high voltage and large current. In this study, an electromagnetic field analysis program is developed and applied to the isolated phase bus. which could be the basic numerical method for the analysis design and modifying isolated phase bus.

• 한국통신학회논문지
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• 제15권2호
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• pp.88-97
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• 1990

時分割 버스 구조를 갖는 멀티프로세서 시스템의 단점을 보완하기 위하여 각 PE의 로칼메모리를 다른 PE가 직접 액세스하는 것이 가능하도록 시스템 버스를 提案하였다. 이를 위하여 이중 입출 메모리 콘트롤러와 중재기를 설계하였으며 이를 이용한 멀티프로세서 시스템의 具現例를 보였다. 性能評價를 위하여 SPN에 의한 모델링과 부하율에 따른 processing power, 效率 및 시스템 버스의 이용율을 측정하였다.

• Journal of Advanced Marine Engineering and Technology
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• 제28권6호
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• pp.1017-1025
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• 2004

Generally generator is connected to the bus with no load. After the connection to the bus. the frequency of generator system with no load has to be increased for preventing the reverse power. But in a few case of parallel running with infinite bus system, we have to synchronize the loaded generator to the infinite bus. The frequency of generator system with load has to be lowered for prevention of load shift to the bus system. The blackout of infinite bus decreases the parallel running generator's frequency because of load increasing. In this paper we propose a method that the generator with load maintains the frequency constantly after the blackout of infinite bus. With the constant speed control and load control method of parallel running system to the infinite bus we apply the method to the industrial generating system.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1992년도 하계학술대회 논문집 A
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• pp.205-210
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• 1992

The power flow calculations are the most important and powerful tools in the various studies of power system engineering. Newton-Raphson method, among the various power flow calculation techniques, is normally used due to its rapidness of numerical convergency. In the conventional Newton-Raphson method, however, there are some unrealistic assumptions, in which all the system power losses are considered to be supplied by the slack bus generator. Introducing the system power loss formula and augmenting the conventional Newton-Raphson power flow method, we can relieve the unrealistic assumption and improve the performance of power flow calculation. In this study, A new approach for handling the losses and augmenting the conventional power flow problem is proposed. The proposed method estimates the increamental changes of active power on each generation bus with respect to the change of total system power losses and the estimated value are used to update the slack bus power. If some studies for more theoritical investigations and verifications are followed, the proposed approach will show some improvement of the conventional method and give lots of contribution to increase the performance of power flow techniques in power systems engineering.

• 대한전기학회논문지
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• 제41권4호
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• pp.346-354
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• 1992

In the power-system, the active and reactive power levels of load bus randomly vary over days, months, and years which are stochastic in nature. This paper presents an algorithm for optimal Var planning considering the uncertainties of loads. The optimization problem is solved by a stochastic linear programming technique which can handle stochastic constraints to evaluate optimal Var requirement at load bus to maintain the voltage profile which results in probabilistic density function by stochastic Load Flow analysis within admissible range. The effectiveness of the proposed algorithm has been verified by the test on the IEEE-30 bus system.

• 전기학회논문지P
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• 제64권1호
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• pp.29-34
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• 2015

DC bus electrolytic capacitors are used in variety of equipments as smoothing element of the power converters because it has high capacitance for its size and low price. It is responsible for frequent breakdowns of many static converters and inverter drive systems. Therefore it is important to diagnosis monitoring the condition of an electrolytic capacitor in real-time to predict the failure of power converter. In this paper, the on-line remote diagnosis monitoring system for DC BUS electrolytic capacitors of power converter using low-cost type Zigbee communication modules is developed. To estimate the health status of the capacitor, the equivalent series resistor(ESR) of the component has to be determined. The capacitor ESR is estimated by using RMS computation using AC coupling method of DC link ripple voltage/current. The Zigbee communication-based experimental results show that the proposed remote DC capacitor diagnosis monitoring system can be applied to DC/DC converter and UPS successfully.

• 대한전기학회논문지
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• 제38권10호
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• pp.805-810
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• 1989

This paper presents a method for planning reactive power compensation such as shunt capacitors and reacters so as to maintain bus voltage in acceptable range during steady state operation in power system. The algorithm in this paper decomposes the problem into reactive power planning module for the compensation of bus voltage and load flow module for adjusting the error resulted from the linear approximation. A planning technique is based on linear programming to minimize the amount of added reactive power compensation in each case. Transformer tap settings and generator voltages are adjusted to minimize the compensation. The constraints are the operation limits of the control variables and bus voltages. The result of one sample system is presented to confirm the practical use of the proposed algorithm.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1996년도 하계학술대회 논문집 B
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• pp.643-645
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• 1996

In order to improve the voltage profile of the system we introduce the reactive power devices. However, it is difficult to know which bus will be the most effective bus when we inject the reactive power supplier in it. This paper systematically determines indices of the system in order to locate reactive power devices in a power system. To prove the validity and effectiveness of the system we apply the proposed method to the 9 bus system.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2009년도 춘계학술대회 논문집
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• pp.536-538
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• 2009

In recent day, many people are interested in wind resource for generation of electric power. Especially, it is made assessment the possibility of generation of electric power by wind resource originated from running cars and buses in downtown or highway. Moreover bus, driven in the exclusive lane, is focused on possibility of generation electric power on highway because median strip makes fast flow way between bus body and median strip and a pattern will appear in the flow way like drag coefficient. But nobody can guess whether the induced flow will increase or decrease and estimate amount of change of drag coefficient. Solving drag coefficient of bus running highway is the point of this paper. To solve this problem, we use the CFD method. The model is a bus simplified without mirror and gates. In order to assess result, the flow analysis surrounding the bus on the flat road where median strip is not installed has been compared with road with median strip. Solving condition is that the driving highway and median strip are running with 100km/h (27.8m/s).

• 대한전자공학회논문지SD
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• 제41권7호
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• pp.71-79
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• 2004

패킷형 데이터전송은 다량의 데이터가 연속적으로 전달되는 특성이 있다. 이와 같은 데이터를 버스를 통하여 전송할 패에 데이터의 전송순서는 버스의 전력소모에 영향을 주는 하나의 요소로서 작용한다. 본 논문에서는 패킷형 데이터를 전송할 때 데이터의 전송순서를 변화시켜 버스의 전이횟수를 줄임으로써 버스의 소비전력을 감소시키는 순서변환코딩 (Sequence-Switch Coding, SSC)을 제안하였다. 또한 SSC를 구현하는 알고리즘을 개발하였으며, 실험을 통하여 이들 알고리즘으로 기존의 널리 알려진 Bus-Invert Coding보다 우수한 성능을 얻을 수 있음을 보였다. SSC는 버스의 소비전력을 줄이는 하나의 방법이며, 이를 실현하는 알고리즘은 무수히 많다. 알고리즘의 다양성은 SSC가 갖는 하나의 장점으로써 회로설계자에게 버스의 소비전력과 회로의 구현부담 사이에서 넓은 범위에 걸쳐 절충할 수 있는 자유를 제공해 준다.