• Journal of the Korean Institute of Intelligent Systems
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• v.9 no.4
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• pp.426-435
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• 1999

A high impedance fault(HIF) is one of the serious problems facing the electric utility industry today. Because of the high impedance of a downed conductor under some conditions these faults are not easily detected by over-current based protection devices and can cause fires and personal hazard. In this paper a new method for detection of HIF which uses adaptive neuro-fuzzy inference system (ANFIS) is proposed. Since arcing fault current shows different changes during high and low voltage portion of conductor voltage waveform we firstly divided one cycle of fault current into equal spanned four data windows according to the mangnitude of conductor voltage. Fast fourier transform(FFT) is applied to each data window and the frequency spectrum of current waveform are chosen asinputs of ANFIS after input selection method is preprocessed. Using staged fault and normal data ANFIS is trained to discriminate between normal and HIF status by hybrid learning algorithm. This algorithm adapted gradient descent and least square method and shows rapid convergence speed and improved convergence error. The proposed method represent good performance when applied to staged fault data and HIFLL(high impedance like load)such as arc-welder.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.54 no.11
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• pp.525-532
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• 2005

This paper presents a new two-terminal numerical algorithm for fault location estimation and for faults recognition using the synchronized phaser in time-domain. The proposed algorithm is also based on the synchronized voltage and current phasor measured from the assumed PMUs(Phasor Measurement Units) installed at both ends of the transmission lines. Also the arc voltage wave shape is modeled numerically on the basis of a great number of arc voltage records obtained by transient recorder. From the calculated arc voltage amplitude it can make a decision whether the fault is permanent or transient. In this paper the algorithm is given and estimated using DFT(discrete Fourier Transform) and the LES(Least Error Squares Method). The algorithm uses a very short data window and enables fast fault detection and classification for real-time transmission line protection. To test the validity of the proposed algorithm, the Electro-Magnetic Transient Program(EMTP/ATP) is used.

• Proceedings of the KIEE Conference
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• 2005.11b
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• pp.283-285
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• 2005

This paper presents a new two-terminal numerical algorithm for fault location estimation and for faults recognition using the synchronized phasor in time-domain. The proposed algorithm is also based on the synchronized voltage and current phasor measured from the PMUs(Phasor Measurement Units) installed at both ends of the transmission lines. Also the arc voltage wave shape is modeled numerically on the basis of a great number of arc voltage records obtained by transient recorder. From the calculated arc voltage amplitude it can make a decision whether the fault is permanent or transient. In this paper the algorithm is given and estimated using DFT(Discrete Fourier Transform) and the LES(Least Error Squares Method). The algorithm uses a very short data window and enables fast fault detection and classification for real-time transmission line protection. To test the validity of the proposed algorithm, the Electro-Magnetic Transient Program(EMTP/ATP) and MATLAB is used.

• Proceedings of the KIEE Conference
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• 2005.07a
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• pp.166-168
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• 2005

This paper presents a new numerical algorithm devoted to one window onto fault location calculation in time domain. It is based on two terminal data processing and it is derived on the synchronized phasor measured from the GPS connected the trans-mission line. The data is obtained by the testing through EMTP (Electromagnetic Tran- sient Program). The proposed the algorithm is estimated using linear least error squares method. The results of the algorithm testing through computer simulation (MATLAB) are presented.

• Proceedings of the KIEE Conference
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• 2015.07a
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• pp.545-546
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• 2015

Arc flash hazard study is required for the electric power system of industrial plant nowadays. Arc flash incident energy and level are calculated by arc flash hazard study. The arcing fault clearing time is determined by the response time of protection devices. This paper is protection devices coordination study to reduce potential incident energy for industrial electric power system.

• Proceedings of the KIEE Conference
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• 2003.07b
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• pp.909-911
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• 2003

The almost pole transformers are constructed with tank, cover, clamp etc., that contains the insulation oil, core, coil, terminals, bus and the other accessories. If some fault current will be flown by some trouble or accident, interior pressure of the transformer shall be very quickly rise, and mechanical components or insulation oil from the transformer enclosure shall be propelled or dropped from the tank. For the prevention of the above accident, recently the pole transformers should be done 'the Design Tests for Fault Current Capability' according to ANSI C57.12.20(1997) There are two tests method in this standard, Test Number I with a high current arcing fault, without internal fusible elements, shall be conducted on rack enclosure with its minimum designed air space. Test Number II with an internal fusible element, shall be conducted on each enclosure diameter utilizing the internal fusible elements. KEPCO recently request to be done the 'Design Tests for Fault Current Capability' for pole transformers according to KEPCO's standard ES141-$533{\sim}545$, PS141-$482{\sim}518$ and RS141-$611{\sim}628$ that is same with Test Number I of ANSI C57.12.20.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.54 no.9
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• pp.391-396
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• 2005

In this paper the modeling of interrupting characteristics of a high voltage current limiting fuse to be used in a power distribution system is introduced. In order to reduce the level of energy which can be absorbed by equipment during fault current flow, a high voltage current limiting fuse can generate a high voltage at the fuse terminals. Consequently it is necessary to model and analyze precisely the voltage and current variation during a CL fuse action. The characteristics of CL fuse operation modeled by electrical components have been performed with less than 6 [$\%$] errors. So the fuse designer or manufacturer can estimate the characteristics of CL fuse operation by using this modeling. The Electro Magnetic Transient Program (EMTP) is used to develop the modeling.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.384-385
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• 2007

The fault current through the earth originated from a power line ground fault might cause arcing through the soil to an adjacent pipeline, which might bring about not only a catastrophic accident such as gas explosion and oil leakage but also a hazard to the safety of workers responsible for the maintenance and repair of the pipeline. In this paper we experimented on the soil breakdown test using the fixture and outlined the standards for the separation distance of a buried pipeline adjacent to the power line tower.

• Fire Science and Engineering
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• v.23 no.1
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• pp.7-14
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• 2009

Several electrical loads such as inrush current, normal operation arcing and non-sinusoidal loads have normal current waveforms similar to arc waveforms. To detect arcs in such loads, therefore, it is necessary to analyze difference between current waveforms with or without arcs. In this paper, using apparatuses of arc generation in UL 1699, arcs are generated in these loads and, then, arc current waveforms are investigated in both the time and the frequency domains to find arc characteristics. This investigation shows that arc current signals have shoulders at some zero current points in the time domain and increment of spectrum magnitude in all over frequency domain. It also shows that the arc characteristics at normal operation arcing and non-sinusoidal loads are detected more easily in the frequency domain than in the time domain. This investigated arc characteristics are expected to be utilized as the basis of development of arc-fault circuit interrupters.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.8
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• pp.1810-1816
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• 2009

In 2007, 9,128 fires were actually caused by electrical faults and these fires resulted in 29 deaths and 262 injuries. Arc-faults were one of the major causes of these fires. When an unintended arc-fault occurs, it generates intense heat that can easily ignite surrounding combustibles. But, because conventional circuit breakers only respond to overloads, short circuits, and leakage currents, the breakers do not protect against arcing conditions. This paper presents results obtained in experiments on ignition behavior of wire by series arc fault currents and techniques developed to detect the arc-faults. The developed technique was tested after installation to make sure that they are working properly and protecting the circuit. If the developed arc fault detection technique is applied, the electrical fires caused by an arc-fault can be reduced.