• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.59 no.5
• /
• pp.847-853
• /
• 2010

This paper describes switching surge analysis for reclosing decision in 345kV combined transmission line with XLPE power cable. Reclosing operation should be decided based on the detailed technical analysis in combined transmission line because this line includes power cable section which is week on insulation. Insulation of power cable can be breakdown at the week point in case of reclosing moment. Therefore the detailed analysis has to be carried out by considering several conditions such as length ratio of power cable section, arrestor, inserting resistance, charging rate, grounding resistance, etc.. On the other hand sheath voltage on IJ(Insulated Joint) is analyzed to check dangerous condition on cable cover. Analysis is performed by EMTP/ATP. Analysis results show that reclosing can be operated as the single line-to-ground fault occurs on overhead line in 345kV combined transmission line, if the inserting resistance is considered before the operation of main circuit breaker.

• International Commerce and Information Review
• /
• v.12 no.4
• /
• pp.363-382
• /
• 2010

It should be unthinkable to not provide water at survival of any living things. Water is too a basic element for development for a country. Currently, the global market of mineral water is growing rapidly. This study, I conceptualized mineral water as bottled water. In particularly, bottled water has seen huge global growth for the last few years. The annual growth rate of the market in the period 2005-2009 was 5.9%. Following a surge in obesity and subsequent health and wellness trends, many consumers are switching from sugary soft drinks to healthier alternatives. Therefore, the global bottled water market is one area which has big potential for growth, but price competition is getting intensified among multi-national and domestic firms. Korean providers too are faced with strong competition in growing domestic market. The bottled water market has presence of multinational provider like Nestle, Danone and Coca-Cola, which collectively account for 35.1% of the world market share in 2009. On the basis of a market orientation approach, this article looks at changing environments in the world mineral water industry and attempts to describe foreign market entry strategy of the Korean mineral water industry. The market orientation provides strong norms for learning from customers and competitors, is instrumental in creating a superior value for buyers, innovating successfully, and generating excellent firm performance. So firms should consider a strategic planning in basis on market orientation before they enter foreign markets. Some discussions were made about managerial implications for Korean bottled water providers.

• The Transactions of the Korean Institute of Electrical Engineers C
• /
• v.48 no.1
• /
• pp.51-56
• /
• 1999

This paper presents a new transient overvoltage blocking device (TOBD) for info-communication facilities with low power and high frequency bandwidth. Conventional protection devices have some problems such as low frequency bandwidth, low energy capacity and high remnant voltage. In order to improve these limitations, thehybrid type TOBD, which consists of a gas tube, avalanche diodes and junction typefield effect transistors (JFETs), was designed and fabricated. The TOBD differs from the conventional protection devices in configuration, and JFETs were used as an active non-linear element and a high speed switching diode with low capacitance limits high current. Therefore the avalanche dilde with low energy capacity are protected fromthe high current, and the TOBD has a very small input capacitance. From the performance test using combination surge generator, which can produce $1.2/50\mus\;4.2kV_{max}\; 8/20\mus\; 2.1kA_{max}$, it is confirmed that proposed TOBD has an excellent protection performance in tight clamping voltage and limiting current characteristics.

• Proceedings of the KIEE Conference
• /
• 2002.11d
• /
• pp.263-266
• /
• 2002

In this paper, It is indicating that an issues of the conventional boost converter for high frequency induction heating. To improve those issues, it is proposed, simulated and analyzed that the current resonant circuit, simulated. As the result, we knew that the proposed circuit has a good point to improve the waveform of input current and to make high efficiency. On the other side, in the inverter for the high current power supply, it is proposed that the high frequency inverter of the half bridge topology, be done the circuit analysis to extract the optimal circuit parameter. It is making sure of the soft switching operating by the inductor to reverse parallel connected on the inverter main switch, decreasing the surge voltage when the switch is turn-off by compulsion, and repressing the switch current and bringing the high current amplitude operation by the multi resonance.

• Proceedings of the KIPE Conference
• /
• 2005.07a
• /
• pp.452-455
• /
• 2005

This paper proposes a new sustaining driver for AC PDP(Plasma Display Panel), which improves the performance of conventional circuit with reduced sustain voltage such as TERES(TEchnology of REciprocal Sustainer). In the TERES circuit, the sustain voltage is the half of general sustaining driver and there is no energy recovery circuit. The circuit proposed in his paper has an energy recovery circuit and removes surge currents. Although the energy recovery circuit is added, the number of active switching elements is the same as the TERES circuit. The operations of the proposed circuit are analyzed for each mode and its validity is verified by the simulations using PSpice program.

• Proceedings of the KIEE Conference
• /
• summer
• /
• pp.48-50
• /
• 2004

The energization of high voltage transmission lines and transformers, that is an inevitable process in most countries as the first restorative action for wide-area blackout, may induce overvoltages such as sustained overvoltage, transient overvoltage and harmonic resonant overvoltage. And these may cause damages to power system equipments or failure of surge arresters. The harmonic resonant overvoltage originates in switching operations and nonlinear characteristics of equipments. Actually it is difficult to predict the occurrence of harmonic overvoltage, since they result from nonlinear characteristics of transformers and other equipments. This paper describes the analysis of domestic primary restorative transmission system using PSCAD/EMTDC. The harmonic resonance is verified and the solution to prevent harmonic resonance is proposed in this paper. As a result, the PSCAD/EMTBC simulation showed slightly conflictive results that had been presented by IEEE Power System Restoration Working Group report.

• Journal of Software Assessment and Valuation
• /
• v.15 no.2
• /
• pp.67-72
• /
• 2019

The recent explosion of data traffic, including cloud services, coupled with the Internet penetration has led to a surge in the need for ultra-fast optical networks that can efficiently connect the data center's reconfiguable resources. In this paper, the algorithms for controlling switching cell operation in the optical switch connection structure are proposed, and the resulting performance is compared and analyzed through simulation. Performance analysis results showed that the algorithm proposed in this paper has improved the probability of successful multi-connection setup by about 3 to 7% compared to the existing algorithm.

• Journal of Advanced Marine Engineering and Technology
• /
• v.34 no.2
• /
• pp.332-338
• /
• 2010

Annually, electrical fires caused by arcing phenomena in power system rapidly increase as the use of more electric appliances, but there is no established method for the prevention of the accidents. With this background, this paper dealt with the experimental results on a series arc detection technique and a device for air conditioners. Series arcing phenomena that is generated in incomplete connection of air conditioners was simulated, and the frequency spectrum was analyzed. The Fast Fourier Transform (FFT) of the arc pulse showed that the dominant frequency components exist in ranges of 190 kHz~250 kHz and 900 kHz~1.6 MHz. An arc detection circuit with low cut off frequency of 170 kHz to attenuate 60 Hz by 170 dB and a signal discriminator were designed. Also, an algorithm which separate series arc signal from unwanted noises produced by switching operation, inverter, and surge was proposed. Application experiment was carried out on several types of air-conditioners by using the arc generator specified in UL1699, and the results showed the over 99 % accuracy.

• Journal of the Korean Society for Railway
• /
• v.12 no.2
• /
• pp.243-248
• /
• 2009

The operation of KTX in Korea has launched since 2004, which brought about a great change in railroad industry. We have acquired lots of great know-hows, especially in railroad construction and operation field. Therefore, we have been building up numerous operation skills until now. However, it was necessary to investigate some of the equipment based on our own environment because the high speed train system were totally imported. In case of Toughened Glass Stem Insulator, it was totally new type in domestic. This paper introduces estimation method and result in three different field aspect, such as an electrical field, a physical field, and environmental circumstances. First, in case of an electrical field, amplitude and a number of time for switching surge voltage data were collected. Second, in case of a physical field, amplitude and trend of vibration in to the insulator were examined. Finally, in case of environmental circumstances, flying possibility of gravel and ice clod were investigated. Also shrink and expend characteristic according to temperature were reviewed. Through this basic data, suitability for Toughened Glass Stem Insulator using in domestic high speed railway have been accumulated and estimated.