• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.1029-1030
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• 2011

최근 녹색성장과 함께 전기자동차에 대한 관심이 높아짐에 따라 전기자동차 Relay 용 Solenoid Actuator에 대한 관심 또한 높아지고 있다. DC Solenoid Actuator는 Electric Vehicle relay(EV-Relay)의 동작을 담당하므로, EV-Relay의 핵심 부분이라 할 수 있다. 본 논문에서는 등가자기회로법을 통해 EV-Relay가 동작하기 위한 DC Solenoid Actuator를 설계하였다.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.65 no.3
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• pp.526-531
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• 2016

This paper presents an experimental study on the optimal settings for the selected DC fault relay (50F) to improve the operating performance for the high-speed circuit breaker on DC feeding system which ensure safety within rolling stock maintenance depot. In this study, current supplied to overhead contact wire was calculated on 1 ms interval to analyze the correction values of DC fault selective relay for the operation of current supply cutout. Particularly, standards for the accurate detection of accidents between an electric railway vehicle and the electric power facilities are shown by investigating the optimal correction values for detection of fault current, and the results indicated that it takes about 213 ms for the DC fault selective relay(50F) to fully open. In the future, the correction values of DC fault selective relay suggested in this paper will be used as the reference values of protective relay for the safe operation of DC electric railroad system such as urban railway.

• Proceedings of the KSR Conference
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• 2008.06a
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• pp.451-465
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• 2008

The DC over current relay(76i) and the DC under voltage relay(mid-point relay, 80A) used mainly with DC protective relay system of DC electric railway in Korea, But the DC fault selective relay(50F) is applying to recently mainly. In this study, simulation to compare 76i/80A and 50F in the methods of protection and the operational characteristics were executed through verifying a calculation of short circuit current and using PSCAD/EMTDC transition program. As a result of this study, it was proved that while 80A runs in relation to the scale of fault resistance, 50F runs regardless of the scale of fault resistance or the length of rail.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.55 no.12
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• pp.646-652
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• 2006

This study identifies the comparison of Technical specification and Characteristics of DC Protection Relay(ETCPU200) used in DC Distribution System in Korea. ETCPU200 has completed Field Test and approved its capability by finding out causes of recent operations through lately developed digital DC protection relay in parallel operation at Maebong-Substation, Sangbong-Substation, Nakseongdae-Substation, Euljirosaga-Substation, Jegi-Substation and Chongyangri T/P area. It also examines additional features for efficient System Analysis and Operations.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.54 no.9
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• pp.427-433
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• 2005

In DC tracking power supply system, ground faults are currently detected by the potential relay, 64P. Though 64P relay detects ground fault, it cannot Identify the faulted region which causes long traffic delays and safety problem to passengers. Two new ground fault protective relay schemes that can identify the faulted region are presented in this paper. One is bus differential protective relay and the other is ground overcurrent protective relay. Both type of relays is similar in principle to the ordinary bus differential protective relay and the ground overcurrent relay used in other power system. In DC traction power supply system, since it is ungrounded, ground fault current is not big enough to operate those relays. To solve the problem, a current control device, called device 'X', is newly introduced in both system, which enables large amount of ground fault current flow upon the positive line to ground fault. Algorithms for these relays are developed and their validity are verified by EMTP simulation.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.64 no.2
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• pp.67-73
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• 2015

Distance relay is widely used for the protection of long transmission line. Most of distance relay used to calculate line impedance by measuring voltage and current using DFT. So if there is a computation error due to the influence of phasor by DC offset component, due to excessive vibration by measuring line impedance, overreach or underreach can be occurs, and then abnormal and non-operation of distance relay can be issue. It is very important to implement the robust distance relaying that is not affected by DC offset component. This paper describes an enhanced distance relaying based on the DC offset elimination filter to minimize the effects of DC offset on a long transmission line. The proposed DC offset elimination filter has not need any prior information. The phase angle delay of the proposed DC offset filter did not occurred and the gain error was not found. The enhanced distance relay uses fault current as well as residual current. The behavior of the proposed distance relaying using off-line simulation has been verified using data about several fault conditions generated by the ATP simulation software.

• The Journal of the Korea institute of electronic communication sciences
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• v.11 no.7
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• pp.653-658
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• 2016

As this paper is related to the relay and its driving control method, it explains about the relay which connects or interrupts the DC high voltage battery's power to drive the electric car's inverter. The paper suggests a sub-relay which prevents strong sparks from relay's contact point when the relay connects to the DC high voltage battery and also compensates for the increasing internal resistance value that is caused by deterioration at contact point. The relay's rated power is approximately 10KW and the relay's electric property has been verified through electrical instantaneous power short test, etc.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.55 no.12
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• pp.529-535
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• 2006

In DC tracking power supply system, ground faults are currently detected by the potential relay, 64P. Though 64P relay detects ground fault, it cannot identify the faulted region which causes long traffic delays and safety problem to passengers. A new ground fault protective relay scheme, ${\Delta}I$ ground fault protective relay, that can identify the faulted region is presented in this paper. In ${\Delta}I$ ground fault protective relaying scheme, ground fault is detected by 59, overvoltage relay, which operates ground switch installed between the negative bus and the ground. It preliminarily chooses the faulted feeder after comparing the current increases among feeders and trips the corresponding feeder breaker. After some time delay, it then recloses the breaker if it finds the preselected feeder is not the actual faulted feeder. Whether or not the preselected feeder is the actual faulted feeder is determined by checking the breaker trip status in the neighboring substation in the direction of the tripped breaker. If the corresponding breaker in the neighboring substation is also tripped, it finally judges the preselected feeder is actually a faulted feeder. Otherwise it recloses the tripped breaker. Its algorithms is presented and verified by EMTP simulation.

• Journal of the Korean Society for Railway
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• v.7 no.4
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• pp.412-417
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• 2004

In urban rail transit systems, ground faults in the DC traction power supply system are currently detected by the potential relay, 64P. Though it detects the fault it cannot identify the faulted region and therefore the faulted region could not be isolated properly. Therefore it could cause a power loss of the trains running on the healthy regions and the safety of the passengers in the trains could be affected adversely. Two new ground fault protective relay schemes that can identify the faulted region are presented in this paper. A current limiting device, called Device X, is newly introduced in both system, which enables large amount of ground fault current flow upon the positive line to ground fault. One type of the relaying schemes is called directional and differential ground fault protective relay which uses the current differential scheme in detecting the fault and uses the permissive signal from neighboring substation to identify the faulted region correctly. The other is called ground over current protective relay. It is similar to the ordinary over current relay but it measures the ground current at the device X not at the power feeding line, and it compares the current variation value to the ground current in Device X to identify the correct faulted line. Though both type of the relays have pros and cons and can identify the faulted region correctly, the ground over current protective relaying scheme has more advantages than the other.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.19 no.2
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• pp.77-86
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• 2005

The DC protection and control device for the feeding system of a Light Rail Transit(LRT) system is developed. For the development, the short circuit characteristics in the system are analyzed. As a result a protection algorithm for the DC fault selective relay (50F) is newly proposed, and principles of the DC fault selective relay, Line Test Device (LTD), DC Over Current Relay (DC OCR) are introduced From the development, the specifications and codes used to be unclear have become clarified and summarized. Moreover, the methods to examine the protective characteristics and Electromagnetic Compatibility (EMC) are established Finally, the performance and the effectiveness of the developed protective relay have been verified with the test based on IEC. For the reliability of the system, the relay has been installed and is being operated at the test track of the LRT system at Gyeong-San.