• 대한전기학회논문지:전력기술부문A
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• 제52권7호
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• pp.363-370
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• 2003

This paper presents the analysis of the load transfer capacity and study of conductor size for variable contingencies in distribution systems. The operation capacity of feeders was changed to improve operation efficiency in KEPCO, considerations for contingencies are still based on the previous capacity. In order to cope with the changes such as operation capacity, it is necessary to study whether the present "contingency support criteria" is reasonable or not, also to confirm the whether the present criteria should be improved or not. We analyze the load transfer capacity and conductor size on a distribution system for contingency levels such as the substation-level, bank-level, feeder-level, and zone-level.one-level.

• 조명전기설비학회논문지
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• 제25권9호
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• pp.56-61
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• 2011

The temperature of power transformers is very important factor for power system operation in substation because load capacity and limited lifetime of power transformers are determined by winding temperature. Also, The temperature of power transformers varies with the structure, capacity, operation condition and manufacturers. Thus, it is necessary for temperature distribution to be exactly investigated because of efficient load management and prediction of limited lifetime. Nevertheless, there was no case of analysis as well as measurement of the temperature of power transformers. In this paper, we manufactured the 154kV standard power transformer for the test. And we measured the temperature by the heat run test and analyzed the temperature distribution of transformer.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 추계학술대회 논문집 전력기술부문
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• pp.103-106
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• 2008

OPNW, which takes charge of the outer neutral wire role and the inner optical network role, was developed at the first time among nation and substituted the neutral wire of distribution line between electric power substation and neighboring station. This paper refers to results about its optical character measured periodically, and examines closely whether the unique matter will be occurred or not about the role of neutral wire during more than one year. Also, established OPNW became a new chance to distribution facility's working by establishing remote portrait supervisory system and doing remote supervisory about essential equipment of distribution line.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2001년도 학술대회논문집
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• pp.51-58
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• 2001

This paper gives a type and high-frequency waves analysis of in-rush current cab be flowed into distribution automatic machine to be installed in distribution line in order to use minimizing operation error of failure indicator to have been issue recent with obtaining high-frequency component that can be different from current. The in-rush and fault current data studied in this paper is to be surveyed actually in USA distribution system substation line of Bryan Power Company near Texas A. M University, to be occurred high impedance fault.

• 전기학회논문지
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• 제59권9호
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• pp.1523-1529
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• 2010

This paper describes the distribution power system econimical PQMS(Power quality monitoring system) of Utility. Recently, the korea power quality standard has been established based on the IEC Std. By IEC Std., the power quality assessment point is measured in PCC(Point of common coupling). In this case, the utility has to construct PQM system in all customer PCC point and the PQ meter cost would be very high in order to acquire the suitable data. Also the distribution system would be encounter the communication overload problem due to the huge data. Accordingly the utilities could not apply to PQM system in the distribution power system by the cost and communication problem. In this paper, the proposed economical PQMS has the voltage and current signal reiteration function and FFT operation function is transferred the server. Also the voltage and current measurement channels are minimized by a classified substation construction.

• Journal of Electrical Engineering and Technology
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• 제3권1호
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• pp.20-28
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• 2008

This paper proposes a method for solving distribution system planning problems taking into account demand uncertainty and geographical information. The proposed method can automatically select appropriate location and size of a substation, routing of feeders, and appropriate sizes of conductors while satisfying constraints, e.g. voltage drop and thermal limit. The demand uncertainty representing load growth is modeled by fuzzy numbers. Feeder routing is determined with consideration of existing infrastructure, e.g. streets and canals. The method integrates planner's experience and process optimization to achieve an appropriate practical solution. The proposed method has been tested with an actual distribution system, from which the results indicate that it can provide satisfactory plans.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1988년도 추계학술대회 논문집 학회본부
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• pp.111-114
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• 1988

With the increase of size and complicacy of power systems, distribution system need to operate effectively for high reliability. In order to achieve this purpose, the study which apply expert system to operating plan, restoration on fault and distribution system operating, has developing actively. The essential element of the study is system line state which make a system observe. The development of expert system on power system operation make a system be able to judge state of loading and looping system line, related current direction, substation, and distribution line, atomatically by breaker operation. Finally, this paper developed expert system which decides itself atomatically by rules for deciding system line state.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 제39회 하계학술대회
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• pp.27-28
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• 2008

For stable and sustainable energy supply, distributed generator (DG) has become an essential and indispensable element from environmental and energy security perspectives. However, installation of DG in distribution systems may cause negative affects on feeders because power outputs of DG could be changed irregularly. One of major negative affects is variation in voltage profile. In general, voltage regulation devices such as under load tap changer (ULTC) at distribution substation and step voltage regulator (SVR) along feeder in distribution system are used to maintain customers' receiving voltage within a predetermined range. These regulators are controlled by line drop compensation (LDC) method which calls for two parameters; the equivalent impedance and the load center voltage. Therefore, consideration of DG outputs in the LDC parameter design procedure may give large impact on the installable DG capacity. This paper proposes a method that estimates maximum Installable DG capacity considering LDC parameters of ULTC and SVR. The proposed algorithm is tested with model network.

• 전기의세계
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• 제18권2호
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• pp.7-14
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• 1969

From the first customer located right at the substation to the last customer at the end of the line, voltage must be held within close limits, so the voltage regulation is more important than the thermal limit. On a typical distribution system during the peak load period, the voltage drop may be serious enough to cause unsatisfactory operation of home appliances in the residential area, and present many problems to manufacturing industries, where the voltage must be maintained within close limits to insure smooth operation. Among all the factors contributing to voltage drop in the distribution system, the voltage drop in the distribution transformer may account for 30% of this figure. If we can eliminate this factor, the power companies can provide better quality electricity to more customers with the existing distribution facilities, thus saving on initial investment costs. Taking all these problems into consideration, the author undertook the design of a capacitive transformer which would give zero voltage drop at rated load and at 80% lagging power factor while incorporating overload features to withstand 400% overload for at least 100 seconds. The following are the results obtained through design, manufacture and test of an initial experimental transformer built with these specific purposes.

• 한국농공학회지
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• 제24권4호
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• pp.80-91
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• 1982

To precict the suspended sediments which are 80% of total sediments in a flood disch- arge, an equation representing vertical distribution of sediment concentration was derived based upon the diffusion theory and the logalithmic velocity distribution function in the tubulent flow mechanism. The hypothesis that the uniform mass transfer is occurred at upper part along the center line of water depth, was established as a preconition to solve the problem. The theorecal and the observed values were compared. And the theoretical equation was modified to be fit the theoretical values the observed values. Observed results are as follow; 1) Equation 12) is the theoretical equation representing the vertical concentration distri- bution of suspended sedimenta 2) Rous&exonential type vertical concentration distribution equation shows signification errors near the water surface. But the equation 12) shows substation cocentration values near the water surface. 3) Equation 15) is the modified theoretical equation which is possible to predict the vertical concentration distribution of suspended sediments.