• Proceedings of the KIEE Conference
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• 2005.07a
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• pp.483-485
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• 2005

In 2003, there was a wide-area blackout in the United States and Canada. More than fifty million people underwent power failure and the estimated financial loss was about four billion dollars. By such wide-area blackouts, the interest in voltage stability has increased gradually. In order to maintain the voltage stability, the preventive control is essential for a contingency. In this paper, a proper preventive control is determined for defined severe contingencies. Among the preventive control methods (generation rescheduling, load curtailment, tap adjusting, injecting the shunt capacitor, and so on.), this paper presents the injection of shunt capacitors by the sensitivity analysis of the voltage stability assessment for preventive controls. The 2006-2010 KEPCO summer peak system is used in case studies.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.05c
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• pp.122-126
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• 2002

A diagnostic test of 15.4kV cross-linked polyethylene(XLPE) ultra high voltage power cables from generator in the Soyanggang hydro electric power plant was conducted over 3 months, beginning April 2001. According to the results, in the case of the power cables from generator 1, there was little possibility of proceeding rapid1y to failure or defect because the data from diagnosis doesn't indicate any failure, deterioration or partial discharge. However, in the case of the power cables from generator 2, the. polarization index show a slight abnormal condition of the insulator that is not severe, and the deterioration was also identified as not severe. However, the partial discharge had an abnormal condition which was severe.

• Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
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• 2000.02a
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• pp.29-32
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• 2000

Superconducting transmission cable is one of interesting part in power application using high temperature super-conducting wire as transformance. One important parameter in HTS cable design is transport current distribution because it is related with current transmission capacity and loss. In this paper, we present the calculation theory of current distribution for multi-layer cable using the electric circuit model and in example, calculation results of current distribution and AC loss in each layer of 4-layer HTS transmission cable.

• Journal of Industrial Technology
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• v.21 no.A
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• pp.207-211
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• 2001

For the power line communication, we studied its characteristic impedance, noise characteristics, loss characteristics and the coupling circuit between the communication MODEM and power lines. As the results of the experiments, we concluded that the power line impedance in a house varied in the wide range because the electric systems generate the current and voltage hamornic noises.

• Proceedings of the KIEE Conference
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• 2009.04a
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• pp.10-12
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• 2009

Electromagnetic Interference(EMI) in electric railway operation has become increasingly important. The components within very high power electronic, and the circuits for treating low-level signals, comprise complex system that must coexist and be highly reliable. To study it, It were included how much the HEMU-400X generates EMI and it has an effect on the power conversion units which resulted from Power Line Disturbance (PLD) phenomenon by contact loss during its running. In this study, the dynamic characteristic of a contact wire and pantograph suppling electrical power to high-speed trains are investigated. The analysis of the loss of contact based on Power Simulator program software is performed to develop power line disturbance model suitable for high speed operation. It is confirmed that a contact wire and pantograph model are necessary for studying the dynamic behavior of the pantograph system.

• Proceedings of the KIEE Conference
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• 2001.05a
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• pp.65-67
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• 2001

This paper presents an application of UML(Unified Modeling Language) to develop the Transmission Loss Calculation Package (TLCP) and shows a feasibility of UML design for the power system analyzing software. In the rapidly restructuring electric power industry, it is required the development of efficient and transparent transmission pricing mechanism. This should be based to calculate an accurate transmission loss to prompt a fair competition and to give unbiased signals to all the market players. For those reasons, it is necessary to develop a software system for transmission loss calculation. In this paper, we design the TLCP based on UML, and describe using Rational Rose 2000.

• Journal of Biosystems Engineering
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• v.40 no.3
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• pp.250-260
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• 2015

Purpose: Dual cylindrical microwave chambers equipped with an ohmic heating tube were designed and fabricated to maximize the electric field strength for expeditious heat treatment of particulate foods. Methods: The efficacy of the combination heater was investigated by simulating the electric field distribution by using COMSOL Multiphysics software. Results: All components of the designed microwave heating unit were suitable for transmitting maximal microwave power to the load. The simulated electric field distribution implied that single-mode microwave heating would be sufficient for the steady generation of a highly localized heating zone in the cavity. During impedance matching, the calculated reflection coefficient ($S_{11}$) was small, possibly implying minimal power loss and wave reflection in the designed microwave heating chamber. Conclusions: This study demonstrates the possibility of concentrating the microwave power at the centerline for a single-frequency microwave, for thermal treatment of multiphase foods without attenuating the microwave power.

• Journal of Electrical Engineering and Technology
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• v.13 no.2
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• pp.580-590
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• 2018

Active distribution system (ADS) considering distributed generation (DG) and electric vehicle (EV) is an effective way to cut carbon emission and improve system benefits. ADS is an evolving, complex and uncertain system, thus comprehensive model and effective optimization algorithms are needed. Battery swapping station (BSS) for EV service is an essential type of flexible load (FL). This paper establishes ADS planning model considering BSS firstly for the minimization of total cost including feeder investment, operation and maintenance, net loss and carbon tax. Meanwhile, immune binary firefly algorithm (IBFA) is proposed to optimize ADS planning. Firefly algorithm (FA) is a novel intelligent algorithm with simple structure and good convergence. By involving biological immune system into FA, IBFA adjusts antibody population scale to increase diversity and global search capability. To validate proposed algorithm, IBFA is compared with particle swarm optimization (PSO) algorithm on IEEE 39-bus system. The results prove that IBFA performs better than PSO in global search and convergence in ADS planning.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.102-103
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• 2007

In order to apply resistive superconducting fault current limiters into electric power systems, the urgent issues to be settled are as follows, such as initial installation price of SFCL, operation and maintenance cost due to ac loss of superconductor and the life of cryostat, and high voltage and high current problems. The ac loss and high cost of superconductor and cryostat system are main bottlenecks for real application. Furthermore in order to increase voltage and current ratings of SFCL, a lot of superconductor components should be connected in series and parallel which resulted in extreme high cost. Thus, in order to make practical SFCL, we designed novel hybrid SFCL which combines superconductor and conventional electric equipment including vacuum interrupter, power fuse and current limiting reactor. The main purpose of hybrid SFCL is to drastically reduce total usage of superconductor by adopting current commutation method by use of superconductor and high fast switch. Consequently, it was possible to get the satisfactory test results using this method, and further works for practical applications are in the process.

• Journal of Energy Engineering
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• v.15 no.4 s.48
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• pp.229-234
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• 2006

Electric energy is too difficult to manage realtime for irregular change of load because of non-storage. In specially, operation of reserve is ancillary service to supply stably to defend large troubles in electric power system. But whole of electric power system brings to economical loss because of reserve operation. Therefore optimal reserve quantity and optimal reserve price are necessary in order to minimize loss. In this paper, we have presents optimal dispatch and reserve price consideration of opportunity cost.