• The Transactions of the Korean Institute of Electrical Engineers A
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• v.55 no.1
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• pp.18-23
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• 2006

Recently as the power system has been becoming massive and complicated, most of the faults bring on severe proliferation effects. Because of the complexity of the power system it is not easy to analyze faults-the calculation of current flows under fault conditions. Therefore many researches have been performed in this area. As a result of those efforts, the protective equipments for a power system have been designed to operate properly and without damage when the highest possible fault current is flowing in the power system. Most of the fault data can be also acquired from intelligent protection equipments. The fault data saved in them don't always include the fault type information. n you don't have knowledge about the fault analysis, it becomes useless. So this paper presents 3 topics to increase a reusability of them as followings. First, describes a fault data using the XML(extensible Markup Language). It would be a well-formed and valid document complied with suggested XML DTD(Document Type Definition). In this paper I suggest a standard DTD to describe the power system fault. If the XML document describes any power system faults is validated against suggested DTD, it is possible to be used in any applications. Second, sends them through the web using the XML web service. Last, presents the rapid and accurate algorithm for a fault type determination of the fault data received from the web. In the ultimate the client to request the server to analyze a fault data is provided the correct information what kind of fault is occurred.

• Proceedings of the KIEE Conference
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• 1999.07b
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• pp.856-858
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• 1999

The analysis of distribution line faults is essential to the proper protection of power system. A high impedance fault(HIF) dose not make enough current to cause conventional protective device. It is well known that undesirable operating conditions and certain types of faults on electric distribution feeders cannot be detected by using conventional Protection system. This paper describes an algorithm using neural network for pattern recognition and detection of high impedance faults. Wavelet transform analysis gives the time-scale information. Time-scale representation of high impedance faults can detect easily and localize correctly the fault waveform.

• Proceedings of the KIEE Conference
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• 2003.11a
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• pp.217-219
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• 2003

This paper presents a distance relaying algorithm for a transmission line protection with MAS. First, the voltage and fault current of the opposite side are represented as a function of those of the measuring end using source voltages of both ends. These voltages are assumed to be obtained from the transformers protecting agents, periodically in normal state. Then, the fault location expression, independent of fault resistance, is derived with voltage and current in only one end of faulted line used. The suggested algorithm is applied to a simple system with two power sources to show its effectiveness.

• Proceedings of the KIEE Conference
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• 2003.07a
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• pp.421-423
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• 2003

To prevent fault effect in supply of electric power distribution system and plan stable operation of electric power system, must control magnitude of fault current. Although there are various kinds of method to solvethis, approached from super conductivity Fault Current Limiter application viewpoint among them. High Temperature Superconductor-Fault Current Limiter (HTS-FCL) development is progressing according to HTS technology development, and system application is tried. For actual system application of such super conductivity FCL, so that can reflect special quality of actuality supply of electric power distribution system just as it is in this treatise supply of electric power system by two modelling do. Also, by simulation of HTS-FCL action and protection coordination with another equipment appliances, verified the effectiveness in supply of electric power system applying itself super conductivity FCL EMTDC dynamic characteristic model that is develope.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.61 no.11
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• pp.1752-1757
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• 2012

With the development in industry, power demand has increased rapidly. As consumption of power has increased, Demand for new power line and electric capacity has risen. However, in the event of fault, problems occur in extending the range of fault coverage and increasing fault current. In these reasons, protection devise is recognized as the prevention of an accident and fault current. This paper dealt with minimizing fault propagation and limiting fault current by adjusting fault current limiter (FCL) with fast interrupter. At this point, we compared and analyzed characteristics between non-inductive resistance and fault current which is limited by superconducting units. In normal state of the power system, power was supplied to the load, but when fault occurred, the interrupter was operated as CT which detected the over-current. Its operation made the limitation of fault current through a FCL. We concluded that the limiter using superconducting units was more efficient with the increase of power voltage. Superconducting fault current limiter with the fast interrupter prevented the spread of a fault, and improved reliability of power system.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.64 no.1
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• pp.35-40
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• 2015

Generators are the most complex and expensive single element in a power system. The generator protection relays should to minimize damage during fault states and must be designed for maximum reliability. A conventional CDR(Current Differential Relaying) technique based on DFT(Discrete Fourier Transform) filter have the disadvantages that the time information can lead to loss in the process of converting the signal from the time domain to the frequency domain. A WT(Wavelet transform) and WT analysis is known that it is possible with the local analysis of the fault and transient signal. In this paper, to overcome the defects in the DFT process, an application of WT for fault detection of generator is presented. This paper describes an selection of mother Wavelet to detect faults of generator. Using collected data from the fault simulation with ATPdraw, we analyzed the several mother Wavelet through the course of MLD(multi-level decomposition) using MATLAB software. Finally, it can be seen that the proposed technique using detail coefficient of Daubechies level 2 which can be fault discriminant of generator.

• Proceedings of the KIEE Conference
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• 2004.11b
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• pp.14-16
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• 2004

A DC railway system has low feeder voltage, The remote fault current can be smaller than the current of load starting. So it is important to discriminate between the small fault current and the load starting current. The load starting current increases step by step but the fault current increases all at once. As for the load starting current, the time constant of load current at each step is much smaller than that of the fault current. To detect faults in DC railway systems, an algorithm using the time constant calculated by the method of least squares was presented. But, It have a weakness about harmonic to calculate time constant. So in this paper, new protection algorithm for DC railway systems using estimation of time constant based on fourier transform was presented.

• Proceedings of the KIEE Conference
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• 1998.07c
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• pp.1244-1246
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• 1998

This paper present a variety fault problem brought out with the multifunctional Battery Energy Storage System [MBESS] expected to be practical in the short future interconnected to power distribution system. Multifunctional BESS model and interconnection model to power system is simply configured, the problems of protection coordination and operation is studied. A line fault in the power distribution system are discussed such as line to ground and three phase fault in order to show the impact on power utilities, demand-side and BESS-side. In order to simulate a variable transient phenomenon due to 2 the BESS interconnection operation to power distribution system, in this paper, PSCAD/EMTDC simulation tools is used.

• Journal of KIISE:Software and Applications
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• v.30 no.12
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• pp.1149-1157
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• 2003

As an Embedded system combining hardware and software gets more complicated, the importance of the embedded software test increases. Especially, it is mandatory to test the embedded software in the system which has high safety level. In embedded system, it is necessary to develop a test technique to detect faults in interaction between hardware and software. In this paper, we propose a test data selection technique using a fault injection technique for the faults in interaction between hardware and software in embedded system and we apply our technique to the Digital Plant Protection System and analyze effectiveness of the proposed technique through experiments.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.63 no.2
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• pp.74-80
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• 2014

Generator protection device has to detects an internal fault conditions in generator and abnormal operating conditions must be due to the hazards. Loss of excitation may cause generator itself failure as well as serious operating problem in power system, and then requires an appropriate response of generator protection device. Details modeling of generator control system and analysis of transient states in generator are important for optimal operation in power plants. In addition, the fault simulation data are also used for testing the characteristics of IED. In this paper, the hydro generator control system using PSCAD/EMTDC, visual simulation for power systems, was modeled. The generator control system which is composed of generator, turbine, exciter, governor was implemented. The parameters of generator control system model were obtained from field power plant. Loss of excitation simulations were performed while varying the fixed load. Several signals analysis were also performed so as to analyze transients phenomena.