• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 제38회 하계학술대회
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• pp.499-500
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• 2007

The existing digital protection relay is continuously growing with an improvement in technology. In this paper, we propose the development of the digital protection relay which displays the trip area in real time. In most of the digital protection relays monitor whether analog signal enters into the pre-determined trip area, but those aren't provide the trip area information for a operator in real time. Therefore, if the digital protection relay continuously displays the trip area in real time, the operator analysis power system status easily. This paper particularly introduces selective ground protective relay and differential protective relay with trip area and presents a method of providing the trip area information to operator in real time.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 제38회 하계학술대회
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• pp.523-524
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• 2007

현재까지 변전소에 구축되어있는 변전소 자동화 시스템은 기존 설비를 바탕으로 지능형 장비(IED)를 추가한, 전력설비 자체의 인텔리전트화가 아닌 2차 설비(제어, 보호, 감시 장치)의 인텔리전트화를 지향하고 있었다. 그러나 본 실증변전소는 CT, PT와 같은 1차 설비에서부터 상위 시스템까지 전체 전력실비를 Intelligent화하였으며, Hardwiring되어 있는 시스템을 모두 통신과 S/W로 처리하였으며, 국내 최초로 Merging Unit을 개발, 적용하여 디지털 계전기를 검증하였다. 또한 향상된 예방진단 시스템 및 보안방재 시스템을 도입하여 변전소종합자동화 시스템을 구축하였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 학술대회 논문집 전문대학교육위원
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• pp.185-190
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• 2006

Frequency and phasor are the most important quantities in power system operation because they can reflect the whole power system situation. Frequency reflects the dynamic energy balance between load and generating power, while operators use phasor to constitute the state of system and, moreover, phasor based line relays are currently used in most power systems. So frequency and phasor are regarded as indices for the operating power systems in practice. The proposed technique is suitable for estimation near-nominal, nomina), and off-nominal frequencies. It is useful in designing microprocessor-based relays and meters that need to measure power system frequency. Performance test results, using signals from EMTP source and Excel program, indicate that the proposed technique can provide accurate estimates within 16ms. Maximum estimation errors observed during testing are of the order of 0.006Hz for nominal, near-nominal, and off-nominal frequencies. The proposed technique provides accurate estimates in presence of noise and harmonics and in case ground fault. The rate change of the phase angle is used for estimation. To confirm the validity of the proposed algorithm, the simulation studies carried out on a typical 154[KV] double T/L system by using EMTP software. Some test results are presented in the paper.

• 전력전자학회논문지
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• 제8권5호
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• pp.381-388
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• 2003

본 논문에서는 IED(Intelligent Electronic Devices)에서의 고조파 문제를 연구하였다. 최근 전력전자 기술의 급격한 발전으로 비선형부하에 의한 전력 품질의 왜곡이 심각해지고 있다. 연속적인 고조파 전류는 전련기기의 수명을 단축시키고 발열 문제가 발생하며 비정상적인 동작을 유발한다. 이러한 문제를 해결하기 위한 디지털 보호계전 시스템에서 전통적인 방법으로 전력을 계측하면 고조파의 영향을 고려할 수 없다. 이러한 문제를 해결하기 위하여 본 연구에서는 TMS320C32 DSP와 CPLD를 이용한 IED prototype을 구현하여 실험을 통해 성능을 확인하였다.

• 대한전기학회논문지:전력기술부문A
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• 제54권8호
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• pp.388-395
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• 2005

It has always been of great importance in the electrical power system to educate an algorithm on the digital relaying, but it is difficult to educate an algorithm of a digital distance relay on power system because of exclusiveness of the relaying algorithm on power system. Therefore, we need a digital distance relay simulator, which can simulate the algorithm of the digital relaying on transmission line. In this Paper, we extract fundamental components using digital signal processing from data which are a variety of the simulated faults by EMTP. Then this simulator represents instantaneous values, ms values and symmetrical components that are calculated by fundamental components of voltages and currents. The Simulator also represents the zones of a digital distance relay and the locus of an impedance using GUI. Consequently, the developed simulator is particularly useful for understanding of the fundamental concepts of a distance relaying algorithm from a power system engineer points of view.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 하계학술대회 논문집 A
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• pp.240-242
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• 2001

On this research, to catch up with international trend on the power system utilities move to be digitalized and move to network is certainly technological on the global business world, to compete with advanced foreign countries in the range of transmit and distribute power system and to take possession of first market share within country, we talked over a monitoring system to diagnose, monitor ACB(Air Circuit Breaker) only which is operated on the low level voltage Power plant. AMS(ACB Monitoring System) have be configured with several modules such as engine module which acquire engineering data from HICM360/860(Communication Control Units) and analyze and save it, database module which restore data and can be inquired, system monitoring view module which reflects fields information within a second, realtime trend window, historical trend window, reports as daily and yearly. In a near future, AMS must upgrade GUI to have easy to handle and have to have a field test to fit on real plants, so it will have faith in system reliability as it can apply power plant monitoring system in wide.

• 한국전기전자재료학회논문지
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• 제32권4호
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• pp.313-319
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• 2019

Induction motors connected with a three-phase AC system may malfunction due to reverse phase or open phase faults. Conventional overcurrent relays and overheating relays are used to prevent such accidents; however, their drawbacks include a low response speed and false operation. Therefore, in this study, a digital relay for the reverse-open phase was designed and fabricated. This relay can detect the reverse phase and open phase faults and send a trigger signal to the control circuit. The proposed relay was developed based on a microcontroller. The detection times of the reverse phase and open phase were verified as 320ms and 80ms, respectively. Compared with conventional relays that only protect the motor from one type of fault, the proposed relay can detect both, reverse phase and open phase faults. In addition, the fault detection, identification criterion, and trigger signal patterns can be modified by programming according to the requirements of users.

• KEPCO Journal on Electric Power and Energy
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• 제6권3호
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• pp.253-257
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• 2020

현장정보처리장치는 아날로그형 전력설비의 전압, 전류, 디지털 전기신호를 IEC 61850 기반 데이터로 변환하여 정보를 처리하는 장치이다. 이는 아날로그형 전력설비의 운전 정보를 취득 및 처리하고, 전력설비의 제어를 수행하며, 내부 로직을 이용하여 인터록 기능 등을 수행한다. 특히, 다수의 보호계전기 입출력 신호를 하나의 장치에서 처리하기 때문에 장치의 입출력 정보를 처리하는 데이터 변환시간이 중요하다. 본 논문에서는 현장정보처리장치의 IEC 61850 통신 기능 및 입출력 데이터 변환시간을 측정할 수 있는 시험 방법과 사례를 소개하고자 한다.

• 한국산학기술학회논문지
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• 제14권12호
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• pp.6427-6433
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• 2013

열차를 안전하면서도 신속하게 운행하기 위해서는 항상 선행열차와 후속열차가 일정한 간격을 유지하면서 운행하여야 한다. 이를 위해 일정한 간격의 폐색구간을 설정하고, 열차의 안전운전을 위해 단일 폐색구간에는 1대의 열차만이 운행될 수 있도록 제어하는 폐색시스템이 필수적으로 요구된다. 기존의 폐색시스템은 신호기에 신호를 현시하는 계전기 방식의 자동폐색장치(ABS: Automatic Block System)로 구성되며, 이것은 연동장치를 통해 궤도회로 등선로변 장치들과 연동된다. 연동장치의 경우 국산 전자연동장치로 교체되고 있지만, 폐색장치는 여전히 아날로그 방식의 계전기 형태를 사용하고 있으며, 다른 선로변 장치들과 독립적으로 설치된다. 따라서 기존의 폐색장치는 건설과 유지보수 측면에서 많은 문제점을 가지고 있다. 또한 현재 국내 기존선에 사용되고 있는 ABS와 선로변 전자장치(LEU: Lineside Electronic Unit)는 동일한 장소에서 동일한 신호 정보에 의해 열차를 제어하고 있음에도 불구하고 별개 시스템으로 분리되어 설치되기 때문에, 각 제품의 단가 및 유지보수 비용 측면에서 효율적이지 않다. 따라서 본 논문에서는 기존 폐색장치인 ABS에 통신 및 디지털 전자 기술을 접목시킨 통합형 전자폐색제어장치(integrated electronic block system)와 그것의 현장시험 결과를 소개한다. 현장시험은 1월초부터 8월말까지 8개월간 총 8번의 주기점검을 통해 시행하였으며, 이를 통해 개발된 전자폐색장치의 유효성과 적합성을 확인하였다.

• 대한전기학회논문지:전력기술부문A
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• 제49권10호
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• pp.516-523
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• 2000

In this paper, intelligent methods using digital protective relay in power supervisory control system is developed in order to protect power systems by means of timely fault detection and diagnosis during operation for induction motor which has various load environments and capacities in power systems. The spectrum pattern of input currents was used to monitor to state of induction motors, and by clustering the spectrum pattern of input currents, the newly occurrence of spectrums pattern caused by faults were detected. For diagnosis of the fault detected, the fuzzy fault tree was derived, and the fuzzy relation equation representing the relation between an induction motor fault and each fault type, was solved. The solution of the fuzzy relation equation shows the possibility of each fault's occurring. The results obtained are summarized as follows: 1) The test result on the basis of KEMC1120 and IEC60255, show that the operation time error of the digital motor protective relay is improved within ${\pm}5%$. 2) Using clustering algorithm by unsupervisory learning, an on-line fault detection method, not affected by the characteristics of loads and rates, was implemented, and the degree of dependency by experts during fault detection was reduced. 3) With the fuzzy fault tree, fault diagnosis process became systematic and expandable to the whole system, and the diagnosis for sub-systems can be made as an object-oriented module.