• 전기의세계
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• v.27 no.6
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• pp.54-57
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• 1978

An analytical investigation has been carried out for the motion of moving element in electro-dynamometer type directional power relay under A.C source. For the more a time dependent kinetic performance of the element can also be deduced for the D.C component in fault current. The results obtained thus for show that, in the relay with stopper, the performance time for the equal D.C and A.C component can be shorten ca. 0.5Hz in comparison with the fact, the performance time exhibits to delay ca. 0.75Hz under the same conditions for the case of the relay without stopper, it appear that these differences of performance times will not give vise any difficultys for the apects of practical case, however, the obtain results can be applicable in the course of the design of the relay.

• Proceedings of the KIEE Conference
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• 2002.07a
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• pp.12-15
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• 2002

Korea Power System Protection Setting Rule was used from the rectify 1990's. Thereafter transmission voltage is raised the voltage into 765kV, and introduction to new technology of Power System, and was many of variation but, it is using. The present is using Digital type distance relay for 765kV transmission line protection. If impedance value of transmission line were to value lower than setting, this would be operating and relay setting rule is for 85% into Zone 1 self section, and Zone 2 is a 125%, Zone 3 is a 225%. Which's $15{\sim}25%$ include current transformer error 5%, potential transformer 5%, relay calculation error 5% and margin factor from the field experience. This paper is discussed transmission protective relay and relay setting rule of high voltage power system and we verify the correctness relay setting rule with distance relay using Matlab simulation.

• Proceedings of the KIEE Conference
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• 2002.07a
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• pp.229-231
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• 2002

The digital current differential relaying scheme is widely used for primary protection of 765(kV) power transformer. The current differential relay pickup the internal fault at the threshold which is set at 30% of rating current. Margin of 30% include current transformer error 5%, relay error 5%, on load tap changer error 7% and margin factor 140% obtained from the field experience. In this paper transformer protection relay and relay setting rule of high voltage power system are discussed. And we verify the correctness of relay setting rule with current differential relay using Matlab simulation.

• Proceedings of the KIEE Conference
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• 2000.07a
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• pp.31-33
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• 2000

This paper discusses the operational characteristic analysis of distance relay depending on the power system parameters in transmission line including FACTS devices. Distance relay requires protective coordination because the FACTS devices change power system parameters to increase power transmission capacity. In this paper, the dynamic operational characteristics of distance relay are analyed for the effect of fault resistance and operation mode of FACTS devices according to the installed points of these devices.

• Proceedings of the KIEE Conference
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• 2006.07a
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• pp.5-7
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• 2006

Current transformers(CTs) whose rating is selected per a full load current of a feeder in high voltage system can be easily saturated due to high fault current that may be several hundred times of the full load current of the feeder. However, the protective relay shall operate properly at the fault without mis-operation under the CT saturation. So, in selecting the CT rating, it is necessary to consider the behaviour of CT and a performance of protection scheme in condition where CT can be saturated. In this paper, a performance of CT and a degree of saturation are studied and verified whether its ratings are proper for the operation of the protective relay.

• Proceedings of the KIEE Conference
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• summer
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• pp.357-359
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• 2004

Fuse is the initial equipment of Protective Relay The installation standard of Fuse has been used for long time in Power Facilities. However according to the innovative development of Electric & Electronic element(=semiconductor) Technology, Protective Relay and other Power Equipments are being changed into Digitalization and Multi-Functional Convergence. In contrast with it, the installation standard of Fuse is just the same. There is a need to give careful consideration to it. This study will bear a Part of producing a safe and efficient Power by examining the current installation of primal 8f secondary 1'use in multi-functional PT of Power plant, giving a problem careful consideration and suggesting suitable countermeasures.

• KIEE International Transactions on Power Engineering
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• v.12A no.1
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• pp.26-30
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• 2002

The four fuzzy criteria to distinguish the internal fault from the inrush fur the power transformer protection have been identified. They are based on the wave shape, terminal voltage, fundamental and second harmonic component of differential current. systematic way to determine the associated fuzzy membership function is also proposed.

• Proceedings of the KIEE Conference
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• 2005.07b
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• pp.1619-1621
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• 2005

AC electric railway feeding system classifies into three groups such as normal, TIE and PP feeding method. If the feeding scheme of ac electric railway is changed, current distribution flowing through the line is also modified. And if the current distribution is altered according to the feeding scheme, returned tendency through rail load current or fault current of the train is changed. So the investigation about error correcting method of protective relay is needed considering feeding scheme. In this paper prior to error correcting of protective relay, through interpreting feeding circuit, changes in current distribution of the rail in accordance with feeding would be predicted and analyzed.

• Proceedings of the KIEE Conference
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• 1996.07b
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• pp.674-676
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• 1996

In this paper, we suggested the verification method of protective algorithms using EMTDC(Electro-Magnetic Transient DC). In other to verify protective algorithms using EMTDC, we first had to make a user defined component and then applied it to a simple power system with parallel line. By means of this method, We reduced the much time and effort to develop or improve the protective algorithm of digital protective relay. For the future, we apply this method to IDPACS(Integrated Digital Protection and Control System) and intend to implement more reliable digital protective relays.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.61 no.1
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• pp.23-28
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• 2012

The market of domestic Power Plant Generator Protection and Control System (GPCS) is narrow and required the high reliability, and technology. So, it is still operated as turn-key. In recent years, digital relays has evolved into IED can perform the control and monitoring functions without central monitoring based on IEC61850 international standards communications, and attention for advancement of smart grid and ECMS has been increased in South Korea. The increasing attention on multi-function IED, DGPS(digital generator protection system), for internal fault protection of large generator results in starting a national project in South Korea, the IED prototype development for next-generation power units. The voltage restrained overcurrent relay have been used as back-up overcurrent protection for generators. In this paper, voltage restrained overcurrent relay is one of the back-up protective factors in generator protection IED was presented. For evaluation performance of the voltage restrained overcurrent relay, the data of ATPDraw5.7p4 modeling was used.