• The Transactions of the Korean Institute of Electrical Engineers A
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• v.52 no.3
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• pp.151-157
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• 2003

Wind farm interconnected with grid can supply the power into a power network not only the normal conditions, but also the fault conditions of distribution network. If the fault happened in the distribution power line with wind fm, the fault current level measured in a relaying point might be lower than that of distribution network without wind turbine generator due to the contribution of wind farm. Consequently, it may be difficult to detect the fault happened in the distribution network connected with wind generator This paper describes the effect of the interconnected wind turbine generators on protective relaying of distribution power lines and detection of the fault occurred in a power line network. Simulation results shows that the current level of fault happened in the power line with wind farm depends on the fault impedance, the fault location. the output of wind farm. and the load condition of distribution network.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.73-74
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• 2007

For a safe operation of HVDC systems, the fault location and clearance of faults in the HVDC lines are important. Past methods for fault location on HVDC cable depend on existence of assistance cables and fault resistance, broken cable and environment of fault location. For complement these problems, in this paper, fault location method using traveling wave and cross correlation function is proposed for HVDC cables. Voltage controlled source and current controlled source HVDC were modeled by EMTDC/PSCAD. The proposed algorithm were verified varying with fault distance, fault resistance.

• Journal of the Korean Institute of Telematics and Electronics
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• v.24 no.3
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• pp.527-534
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• 1987

This paper proposes a new syndrome-testable design method for large MOSPLA's. In the conventional syndrome test method, the testing array circuit for testability is added but it has the defect that the circuit gives effect on the normal operation of the basic PLA circuit. Therefore, by adding the shift registers to the product lines of the basic MOSPLA's this defect is eliminated and the number of test patterns is decreased. In order to reduce the number of fault free syndromes to be predetermined, also, one output line, which is connected to all product lines is added. Therefore the number of output lines be observed is decreased. And the analytical method to compute fault free syndromes is presented. By unsing this method, the time and the effort to compute the syndromes are decreased.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.51 no.4
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• pp.163-168
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• 2002

This paper present a new verb efficient numerical algorithm for arcing faults detection and fault distance estimation in transmission line. It is based on the fundamental differential equations describing the transients on a transmission line before, during and alter the fault occurrence, and on the application of the "Least Error Squares Technique"for the unknown model parameter estimation. If the arc voltage estimated is a near zero, the fault is without arc, in other words the fault is permanent fault. If the arc voltage estimated has any high value, the faust is identified as an fault, or the transient fault. In permanent faults case, fault distance estimation is necessary. This paper uses the model of the arcing fault in transmission line using ZnO arrestor and resistance to be implemented within EMTP. One purpose of this study is to build a structure for modeling of arcing fault detection and fault distance estimation algorithm using Matlab programming. In this paper, This algorithm has been designed in Graphic user interface(GUI).

• Journal of Electrical Engineering and Technology
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• v.12 no.6
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• pp.2118-2126
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• 2017

The large-scale power system blackouts have indicated that conventional protection relays that based on local signals cannot fit for modern power grids with complicated setting or heavily loaded-flow transfer. In order to accurately detect various faulted lines and improve the fault-tolerance of wide-area protection, a novel multi-section weighed fault matching and detecting algorithm is proposed. The real protection vector (RPV) and expected section protection vectors (ESPVs) for five fault sections are constructed respectively. The function of multi-section weighed fault matching is established to calculate the section fault matching degrees between RPV and five ESPVs. Then the fault degree of protected line based on five section fault degrees can be obtained. Two fault detecting criterions are given to support the higher accuracy rate of detecting fault. With the enumerating method, the simulation tests illustrate the correctness and fault-tolerance of proposed algorithm. It can reach the target of 100% accuracy rate under 5 bits error of wide-area protections. The influence factors of fault-tolerance are analyzed, which include the choosing of wide-area protections, as well as the topological structures of power grid and fault threshold.

• Journal of Electrical Engineering and Technology
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• v.3 no.4
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• pp.460-467
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• 2008

This paper presents a new numerical algorithm for the fault location estimation and arcing fault detection when a single-phase arcing ground fault occurs on a transmission line. The proposed algorithm derived in the spectrum domain is based on the synchronized voltage and current samples measured from the PMUs(Phasor Measurement Units) installed at both ends of the transmission lines. In this paper, the algorithm uses DFT(Discrete Fourier Transform) for estimation. The algorithm uses a short data window for real-time transmission line protection. Also, from the calculated arc voltage amplitude, a decision can be made whether the fault is permanent or transient. The proposed algorithm is tested through computer simulation to show its effectiveness.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.45 no.2
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• pp.167-174
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• 1996

In this paper, a fault location algorithm is presented, which uses novel signal processing techniques and takes a new paradigm to overcome some drawbacks of the conventional methods. This new method for fault location on electric power transmission lines uses only one-terminal fault signals. The main feature of the method is hat it uses the high frequency components in fault signal and considers the influence of the source network by using a traveling wave propagation characteristics. As a result, we can develop a high speed, good accuracy fault locator.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.64 no.12
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• pp.1659-1665
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• 2015

In general, AT(Auto-transformer) is used to improve voltage sag and inductive interference in power lines and communication lines in AC electrical railway feeding system. Especially, Korean AT feeding system has different composition compared to other countries like Japan or France, so that it has some special characteristics. However, relays imported from other countries have been used in Korea, and settings of these relays should be modified and reflect distinct characteristics of Korean AT feeding system. Therefore, study about fault analysis based on modeled AT feeding system is important. In this paper, we modeled a single track AT feeding system by using PSCAD and analyzed fault current flow in case of trolley-rail short circuit fault. Finally, we presented current magnitude of each branch expressed by boosting current of AT.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.27 no.7
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• pp.37-44
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• 2013

Phase to ground faults are possibly one of the maximum number of faults in power distribution system. During a ground fault the maximum fault current and neutral to ground voltage will appear at the pole nearest to the fault. Distribution lines are consisted of three phase conductors, an overhead ground wire and a multigrounded neutral line. In this paper phase to neutral faults were staged at the specified concrete pole along the distribution line and measured the ground fault current distribution in the ground fault current, three poles nearest to the fault point, overhead ground wire and neutral line. A simplified equivalent circuit model for the distribution system under case study calculated by using MATLAB gives results very close to the ground fault current distribution yielded by field tests.

• Proceedings of the IEEK Conference
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• 1998.06a
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• pp.54-57
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• 1998

As the physical layer on telecommunication network is replaced fiber optic lines, it is increased the need of systematic maintenance for fiber optic lines. Korea Telecom has developed FLOMS in order to establish maintenance processes for optical fiber lines. FLOMS has functions which manages optical facilities and tests optical fiber lines automatically. As a resuls, this system can check and/or report a fault. Operator, who is reponsible for management of optical fiber lines, can test the characteristics of optical fiber lines remotely using FLOMS. As interpoerable with Digital Transmission Management System, FLOMS provides efficient management for optical fiber lines. This system improves the work process to find fault location fast, detect the degradation of fiber quality, and make database of optical facilities efficiently.