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Gyeonggi, South Korea

Jung S.,Korea University | Lee H.,Kyungil University | Song C.S.,Korea University | Han J.-H.,Korea Electrotechnology Research Institute | And 2 more authors.
IEEE Transactions on Power Electronics | Year: 2013

Owing to the consistent increase in energy efficiency issues, studies for improving the charging efficiency and energy density of batteries have been receiving attention in the electric vehicle transportation sector. This paper deals with an online electric vehicle (OLEV) system which utilizes the dc power system for reducing loss as well as reducing the size of the required battery capacity. Intensive research on grid integration with OLEV has not been performed until recently and it is necessary to calculate the power flow analysis considering the unique characteristics of OLEV for the commercialization of this new transport system (for the application of this new system in the transport sector). In this paper, the dc OLEV power system is being investigated for reducing line losses and peak power thereby reducing the electric cost levied on the substation. Verification processes are performed through simulation for various scenarios to examine the effectiveness of the proposed system in terms of power consumption, battery state of charge, peak power, and loss reduction. © 1986-2012 IEEE.

Kil G.-S.,Korea University | Gil H.-J.,Korea Electrical Safety Corporation | Park D.-W.,Korea University
Journal of Electrical Engineering and Technology | Year: 2012

This paper proposes a reduced-scale simulator that can replace numerical analytic methods for the estimation of potential distribution caused by ground faults in various grounding systems. The simulator consists of a hemispherical electrolytic tank, a three-dimensional potential probe, a grounding electrode, and a data acquisition module. The potential distribution is measured using a potentiometer with a position-tracing function when a test current flows to the grounding electrode. Using the simulator, we could clearly analyze the potential distribution for a reduced- scale model by one-eightieth of the buried depth and length of the grounding rod and grounding grid. Once both the shape of the grounding electrode and the fault current are known, the actual potential distribution can be estimated.

Choi S.-H.,Soongsil University | Huh J.-S.,Soongsil University | Han W.-K.,Korea Electrical Safety Corporation | Kim J.-C.,Soongsil University
Transactions of the Korean Institute of Electrical Engineers | Year: 2014

Recently, various measures have been discussed for overcoming depletion of fossil fuels and environmental pollution. One of the measures is electric vehicles. But electric vehicles has some limitations from high cost of battery and low efficiency, so operation distance of electric cars is limited. Also there are difficulties that charging lines should be connected by an electric car whenever it charges. Thus, many studies have been conducted to overcome the limitation using conventional batteries of electric vehicles. As a result, the OLEV(On-Line Electric Vehicle) was developed. But the OLEV system is some limitations. The OLEV system causes power quality problems when it charges. Power quality problem cannot be ignored because OLEV systems are closely connected by distribution grids. In this paper, the OLEV system is designed by using PSCAD/EMTDC, and the power quality is measured and evaluated. Power quality is divided by two cases; harmonics and high-frequency. Harmonics were evaluated according to IEEE Std. 519-1992. But the evaluation of High-frequency could not take it because there was no standard. For this reason, the data measured by OLEV system was compared with the EN50065 regulation.

Shin H.-K.,Inha University | Kim D.-S.,Korea Electrical Safety Corporation | Chung Y.-K.,OMNI LPS Co. | Lee B.-H.,Inha University
2014 International Conference on Lightning Protection, ICLP 2014 | Year: 2014

Surge protective devices (SPDs) play an important role to protect the valuable electrical and electronic equipment against transients originating from lightning. Class I tested SPDs are needed to divert surge currents due to direct lightning flashes. In order to achieve the effective protection of sensitive electrical and electronic systems, coordinated SPD systems should be designed and installed. This paper presents the experimental results obtained from the actual installation conditions of SPDs with the aims to understand the energy sharing of the cascaded Class I and II SPDs and to propose the effective selection and installation methods of SPDs. The residual voltage of each SPD and energy coordination between the upstream Class I tested SPD and the downstream Class tested II SPD were measured using a 10/350 μs current wave. © 2014 IEEE.

Kim S.H.,Gyeongsang National University | Choi J.H.,Gyeongsang National University | Kim W.J.,Gyeongsang National University | Kim K.L.,Korea University | And 4 more authors.
IEEE Transactions on Applied Superconductivity | Year: 2012

A high-temperature superconducting (HTS) DC cable system has attracted a great deal of interest from the view point of low loss, dense structure and large capacity compared to HTS AC cable system. It has a HTS cable and a termination. A HTS DC cable system consists of a conductor, cooling system and electrical insulation. To realize the HTS DC cable system, it is important to study not only high current capacity and low loss of conductor but also optimum electrical insulation at cryogenic temperature. The electrical insulation technology of HTS DC cable and termination must be solved for the long life, reliability and compact of cable.In this paper, we will discuss mainly on the electrical insulation characteristics and the insulation design of 220 kV class HTS DC cable. Voltage-time (V-t) characteristics of laminated polypropylene paper (PPLP) in LN 2 were studied. Furthermore, the surface flashover characteristics of glass fiber reinforced plastic (GFRP) for termination insulators under DC and lightning impulse voltage were studied. © 2011 IEEE.

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