• The Transactions of the Korean Institute of Electrical Engineers A
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• v.52 no.4
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• pp.213-218
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• 2003

In front of the opening of electric distribution market in 2004, it is indispensable to have a proper estimation of power quality index and rower quality cost calculation mechanism which are indispensable to stabilize highly industrialized society and to vitalize the Investment lot electric power system. However, there were not enough measures to reflect the voltage characteristics such as voltage sags and Interruptions which make electric load in unstable operation. This paper suggests power quality index and power quality cost which translate various kinds of voltage records into bus load drop index(BLDI) and bus power quality cost(BPQC) based on aggregated load CBEMA curve. A sample calculation result shows that this method can produces the acceptable power Quality index and costs for utilities and customers requirements.

• Corrosion Science and Technology
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• v.18 no.4
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• pp.117-120
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• 2019

Considering the tendency of development of electrification vehicles, development and verification of new evaluation technology is needed because of new technology applications. Recently, as the battery package is set outdoors of an electric vehicle, such vehicles are exposed to corrosive environments. Among major components connected to the battery package, rust prevention of high-voltage cables and connectors is considered the most important issue. For example, if corrosion of high voltage cable connectors occurs, the corrosion durability assessment of using an electric vehicle will be different from general environmental corrosion phenomena. The purpose of this study is to investigate the corrosion mechanism of high voltage cable connectors of an electric vehicle under various driving environments (road surface vibration, corrosion environment, current conduction by stray current, etc.) and develop an optimal rust prevention solution. To improve our parts test method, we have proposed a realistic test method to reproduce actual electric vehicle corrosion issues based on the principle test.

• Journal of the Korean Society of Industry Convergence
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• v.26 no.6_1
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• pp.985-991
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• 2023

This study proposes a solution to the voltage drop in electric vehicle chargers, due to the parasitic resistance and inductance of power cables when the chargers are separated by large distances. A method using multi-level electric vehicle chargers that can output power in stages, without installing an additional energy supply source such as a reactive power compensator or an energy storage system, is proposed. The voltage drop over the power cables, to optimize the charging scheduling, is derived. The obtained voltage drop equation is used to formulate the constraints of the optimization process. To validate the effectiveness of the obtained results, an optimal charging scheduling is performed for each period in a case study based on the assumed charging demands of three connected chargers. From the calculations, the proposed method was found to generate an annual profit of $20,800 for a $12,500 increase in installation costs.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.61 no.12
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• pp.1953-1958
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• 2012

The major causes of electrical fire are classified to short circuit fault, overload fault, electric leakage and electric contact failure. The occurrence factor of the fire is electric arc or spark accompanied with such electric faults, specially short circuit faults. Earth Leakage Circuit Breaker (ELB) and Molded_case Circuit Breaker (MCCB), that is, Residual Current Protective Devices (RCDs) used on low voltage distribution lines cut off earth leakage and overload, but the RCD can not cut off electric arc or spark to be a major factor of electrical fire. As the RCDs which are applied in low voltage distribution panel are prescribed to rated breaking time about 30ms(KS C 4613), the RCDs can't perceive to the periodic electric arc or spark of more short wavelength level. To improve such problem, this paper proposes a prevention apparatus using the line voltage drop of neutral wire and some semiconductor switching devices. Some experimental tests of the proposed apparatus confirm the validity of the analytical results.

• Journal of the Korean Society of Safety
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• v.4 no.1
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• pp.83-90
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• 1989

Recently, due to the increase of 220V distribution lines and equipments preventive measures to cope with several kinds of electric accidents is revealed as an urgent problem. This study investigates the following matters; the cause and present condition of e1ectric shock accident, the influence of electric shock on human body, the safety limit of electric shock, the method of distribution voltage, the insulation of electrical load apparatus, the teachnics of electric shock prevention and foreign materials concerned with this subject etc. This paper present the fundamental cause of electric shock and syntbetic preventive counter measure of electric shock, too.

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.1997-2004
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• 2011

The $2{\times}25kv$ AT electric power feeding method in the A.C. electric train adopts the one-phase power feeding method as the standard due to a voltage phase difference, and the distance between the two neighboring substations is 50km due to voltage drop. The one-phase power feeding method makes the system operation feasible, while making it unfavorable for power supply. Moreover, railroad involves large-capacity single-phase load, and if it is expected to continue to rise, it is necessary to research on measures to stabilize the supply of power to railroad cars with the existing facilities. In this study, a parallel power feeding method between neighboring substations is proposed to stabilize the supply of electric power to electric railroad cars under the 2*25kv AT power feeding method and the loop current induced by voltage phase difference between the two neighboring substations during parallel power feeding is investigated.

• Proceedings of the KIEE Conference
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• 2006.07a
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• pp.329-330
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• 2006

The purpose of this paper is to compensate the voltage drop of the power system in the AC Electric Railway Systems. Reactive power compensation is often the most effective way to improve system voltage drop. The suitable modeling of the electric railway system should be applied to the EMTP. the dynamic characteristics of 3-Phase Induction Motor in Electric Railway Systems is considered for precise modeling. it is shown through EMTP simulation using EMTP MODELS that voltage drop can be compensated effectively by STATCOM.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2009.05a
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• pp.305-308
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• 2009

This paper resents a study on the electric facilities plan and application of low-voltage grid connection for a photovoltaic electric power station. The analysis for an installation cost is carried out and a new plan to solve the problem caused by a voltage drop in a low-voltage grid connection is devised. It is expected that the results can be usefully applied to spread the photovoltaic electric power station.

• Proceedings of the KIEE Conference
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• 1994.11a
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• pp.287-289
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• 1994

This paper deals with the planar-type electric field sensor which can measure the time-varying electric fields. The theoretical principle and design rule of the sensor are introduced, and also the calibration and application investigations are carried out. From the calibration experiments, the frequency bandwidth of the measurement system ranges from 160 [Hz] to 25 [MHz]. At a high voltage laboratory, the electric fields caused by the impulse voltage and oscillating transient voltage are measured by the proposed sensor. Obtained results are well agreement with the applied voltage waveforms.

• Journal of Biosystems Engineering
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• v.35 no.2
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• pp.100-107
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• 2010

This study was conducted to investigate the effects of electric current stimuli and high-voltage electric field treatments on brown rice germination. The brown rice stimulated by electrical current stimuli, functional electrical stimuli of a pulse type, and high-voltage electric field treatments were observed (Type I, II and III). Treatment Type I was a method of semi-soaking brown rice with electric current stimuli of 0.13 V/cm, 0.19 V/cm, and 0.25 V/cm into Petri-dishes for 72 hours. Type II was a method of semi-soaking brown rice with functional electrical stimuli of a pulse type(DC 1 V, 1 Hz, 5%, and duty cycles of 5%, 20%, and 35%) into Petri-dishes for 72 hours. Type III was a method of water-soaking with high-voltage electric field treatments for 60 hours. High-voltage electric field treatments at 15 kV/cm were also conducted for 2.5 min, 7.5 min, and 10 min, respectively. The germination rate and the sprout growth of brown rice germinated by electric current stimuli with 0.13 V/cm, 0.19 V/cm, and 0.25 V/cm were increased by about 10-15% compared with those of the control group. The germination rate and the sprout growth of brown rice germinated by functional electrical stimuli of pulse type(DC 1 V, 1 Hz, 5% duty cycle) were increased by about 10∼15% compared to those of the control group. Also, the best effective treatment among high-voltage electric field treatments was the 10 min group at 15 kV/cm. The germination rate and the sprout growth of brown rice germinated by this treatment of 10 min at 15 kV/cm were increased by about 10∼20% compared to those of the control group. The treatments of electric current stimuli and high-voltage electric field accelerated the germination rate and sprout growth of brown rice by about 10∼15% compared to those of the control group.