• 대한전기학회:학술대회논문집
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• 대한전기학회 1992년도 하계학술대회 논문집 B
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• pp.666-668
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• 1992

This paper shows a reasonable design standard of electric equipment capacity for office buildings, that was made by the systematic and statistical way considering actual conditions, such as investigated electric equipment capacity, electric power consumption, etc for 121 buildings. The saving of electric equiment investment, the decrease of power loss, the improvement of facilities utilization and the decreasse of electric power rates can be contributed by the application of the design standard.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2000년도 추계종합학술대회 논문집(1)
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• pp.117-120
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• 2000

This paper discusses solutions for forward link power allocation based on 3GPP(FDD) standardization reports and which meet the required Eb/No of forward link channels. In addition, the forward link user capacity in a mixed service environment. Cell coverage is induced from the user capacity solutions using the urban propagation model. In an urban macrocell environment, the forward link user capacity turns out to be roughly 29 and 3, respectively, for voice and data service (144 kbps) at a distance of 1 km, and in an urban microcell environment, the user capacity turns out to be Toughly 14, 4, and 2, respectively, for voice and two data services (144 kbps, 384 kbps) when the cell radius is 0.2 km.

• Journal of Power Electronics
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• 제13권3호
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• pp.497-506
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• 2013

This paper proposes a new method to improve the available battery capacity in electric vehicles by connecting lead-acid batteries with lithium-ion battery in parallel to supply power. In addition, this method combines the discharge characteristics of batteries to improve their efficiency and lower their cost for electric vehicles. A lithium-ion battery set is used to connect with N sets of lead-acid batteries in parallel. The lead-acid battery supplies the initial power. When the lead-acid battery is discharged by the load current until its output voltage drops to the cut-off voltage, the power management unit controls the lead-acid battery and changes it to discharge continuously with a small current. This discharge can be achieved by connecting the lead-acid battery to a lithium-ion battery in parallel to supply the load power or to discharge its current to another lead-acid or lithium-ion battery. Experimental results demonstrates that the available capacity can be improved by up to 30% of the rated capacity of the lead-acid batteries.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 하계학술대회 논문집 D
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• pp.2187-2189
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• 2001

The proposed algorithm has produced the rules of relationship between the load voltage, current, discharging electric power and ampere-hours, electric power capacity of battery on the basis of the data. Which were acquired through the battery discharging experiment that is defined by the battery's ambient temperature and various load conditions. Especially, by calculating the parameter of second order polynomial equation relation between the remaining capacity and the electric power, the algorithm is proposed adapting for the discharging pattern. And as the depth of discharging is increasing, the calculation-method of electric power is applied to decrease the accumulated error in the calculation method of capacity accumulation. Also, the proposed algorithm has compensated the temperature considering the capacity change of battery to the temperature.

• 전기학회논문지
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• 제58권10호
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• pp.1911-1915
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• 2009

The problem of determining the proper capacity of electric vehicle charging station is studied in the presented paper. Based on the expected arrival rate and the expected charging time, we calculate the proper capacity that guarantees electric vehicles get service better than a given lower bound which is termed the loss of charging probability. The problem is studied by using certain queueing models. We first formulate the problem as a queueless model of type M/M/n/n, known as the Erlang loss system. And then the M/M/n/K type queueing model is formulated to consider the parking space constraint. Results of the study may be used for designing the electric vehicle charging station.

• Journal of Power Electronics
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• 제19권5호
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• pp.1315-1325
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• 2019

Aiming at the negative sequence and harmonic problems in the operation of railway static power conditioners, an optimization compensation strategy for negative sequence and harmonics is studied in this paper. First, the hybrid RPC topology and compensation principle are analyzed to obtain different compensation zone states and current capacities. Second, in order to optimize the RPC capacity configuration, the minimum RPC compensation capacity is calculated according to constraint conditions, and the optimal compensation coefficient and compensation angle are obtained. In addition, the voltage unbalance ${\varepsilon}_U$ and power factor requirements are satisfied. A PSO (Particle Swarm Optimization) algorithm is used to calculate the three indexes for minimum compensating energy. The proposed method can precisely calculate the optimal compensation capacity in real time. Finally, MATLAB simulations and an experimental platform verify the effectiveness and economics of the proposed algorithm.

• Journal of Platform Technology
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• 제11권2호
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• pp.54-65
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• 2023

전기자동차에 사용되는 배터리는 전기자동차의 특성상 정격용량이 매우 커다란 배터리이다. 전기자동차를 장기간 운행하거나 교통사고로 전기자동차가 폐차되게 되면 전기자동차용 배터리는 폐배터리가 된다. 폐차되는 차량이더라도 전기자동차용 폐배터리에 남아 있는 용량은 다른 용도로 사용하기에 충분하다. 자동차용 폐배터리는 매우 고가이기때문에 재활용 및 재사용이 필요하지만 재활용 및 재사용을 위한 폐배터리 성능등급 측정기준이 부족한 문제가 있었다. 폐배터리의 잔존용량을 측정하는 방법으로 가장 안정적이고 신뢰할 수 있는 방법은 완전 충·방전을 이용하여 배터리의 잔존용량을 측정하는 것이다. 하지만 이러한 완전 충·방전에 방식에 의한 검사 방법은 배터리의 용량에 따라 다르지만 검사하는데 하루 이상이 걸리는 단점을 가지고 있으며 많은 사람들이 이러한 문제를 해결하기 위하여 많은 노력을 하고 있다. 본 논문에서는 전기자동차 배터리에 대한 검사 시간을 줄일 수 있는 방법으로 셀간 전압 편차를 활용한 전기자동차 배터리 잔존용량 분석 기법을 연구 분석하였다. 이를 위하여 완전 충·방전 기반의 용량 측정시스템을 구성하고 코나 폐배터리를 이용하여 실험데이터를 수집하였고 배터리 팩을 구성하고 있는 배터리 셀간 전압 편차와 잔존용량과의 상관관계를 분석하여 배터리 검사에 활용할 수 있는지를 검증하였다.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2006년도 추계학술대회 논문집
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• pp.844-849
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• 2006

The electric facilities for subway stations require reliable and safe electricity in spite of their load increases rapidly. Nevertheless, Korea Electrical Safety Corporation reports that the accidents of independent electric facilities increased greatly from 4,632 cases in 1998 to 6,024 in 1999 and 6,776 cases in 2000, while the ratio of the accidents related with transformers grew gradually. As it is, it is deemed very important to minimize the spreading effects of the electric system accidents and thereby, enhance reliability of the electric supply as well as its safety. According to the fact that the electric facilities for subway stations are important for the public safety and conveniences, it should be careful to set their capacity instead of simply applying the general capacity standard to them, and thereby, improve their economy as well as prevent their accidents. With such a basic conception in mind, this study is aimed at analyzing the characteristics of the electric load in the subway stations and thereupon, suggesting some guidelines for setting of the electric facility capacity for subway stations in terms of optimal operation and safety.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 하계학술대회 논문집 A
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• pp.443-445
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• 2001

As the new large buildings are continuously being built with the advanced technology and skills, an adequate size of electric room needs to be obtained so that engineers establish an efficient and reliable system in the electric room. Considering the current capacity, its expansion and its connecting system, the final size of it should be determined in order to bring an effective use of the building. Usually the extension of electricity capacity is on the increase after construction and it comes from the lack of scientific evaluation on the electric room. Later when the expansion of computer and important electric equipment that needs much capacity is impossible, it will cause a great deal of damage to the renting business of the building as well as becomes the unstable factors of the whole system. Therefore, it is important to have the exact method of calculating the effective size of electric room, the heart of the building, especially when the value of land price is very high. In addition, it should be calculated in an accurate way due to the diversification of the system and the compact size of the electricity equipment. However, the research on this area and the comparison and evaluation of the size after construction have not been made enough and the results of them have not been applied when calculating a new size of electric room. Accordingly, this study examines three methods prescribed in the standards of electricity installation technology through case analysis and suggests substantial data by system, capacity, and purpose.

• KEPCO Journal on Electric Power and Energy
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• 제8권2호
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• pp.181-187
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• 2022

As the charges/discharges of VRFB-ESS were repeated during 150cycles or more, the capacity of electrolyte in VRFB-ESS was decreased little by little. It results from the decreasing of the level of anolyte and the increasing of the valance value of the catholyte. Then, we tried to recover the capacity loss with 3 different ways. The first way was that the levels of anolyte and catholyte were allowed to be evenly equalized when the difference in the levels of two different electrolytes were severe. The second one was to lessen the valance value of the catholyte through the reduction reaction to 4-valant ions of 5-valant ions in the catholyte with the reductant, oxalic acid. The last one was that the all electrolytes of analyte and catholyte were allowed to be electro-chemically reduced to 3.5 of the valance value by oxidizing new electrolyte with 3.5 valance ions. The last way was the most effective to recover the capacity loss.