• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 하계학술대회 논문집 A
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• pp.188-190
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• 2000

Protective Relays are vital components of power systems. The role of the protective relaying device is more important than ever. Therefore, We have investigated the operating trends of protective relay from 1991 to 1999. we anticipate that reliability in the power systems increases by improving design, manufacture, construction technology and maintenance method of the protective relay.

• 대한전기학회논문지:전력기술부문A
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• 제53권11호
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• pp.581-588
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• 2004

Power qualify monitoring system is devoted to more concern than before, because the innovation of industrial technology needs more accurate instruments and more advanced power quality. This paper was studied on using data of the protective relay by Power Quality Monitor. This paper was proposed the wave storage condition and monitoring clauses of the protective relay as a power quality monitoring device. The protective relay will have problem to save data for PQM analysis because the protective relay memory is limited. Therefore this paper was proposed new a data compression of data got from the protective relay. This method is wave compression comparison algorithm using the DFT. The compression rate is higher than any other established method. This method can be real time storage. This algorithm is verified using the comparison among other compression rate and proved by Real Time Digital Simulator (RTDS).

• 대한전기학회:학술대회논문집
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• 대한전기학회 1993년도 하계학술대회 논문집 A
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• pp.152-155
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• 1993

Protective Relay in power system play a prominent part in minimizing power delivery interruptions and help to get a fast and secure restoration when a failure occurs. In order to meet the higher functional requirements in power system, the performance tests on response characteristic of protective relay is essential to ensure reliability. The purpose of this study is as follows: In order to evaluate performance of protective relay, it is intended to develop performance of digital protective relay simulator which is composed of digital protective relay part, behaviour analysis part, waveform generation part and simulation program to simulate pour system in detail.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 하계학술대회 논문집 A
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• pp.311-313
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• 2003

There have been public attraction and studies about distributed generation systems. But protective relay must be installed between utility system and customer owned distributed generation system has not been developed. So this paper describes the development of a digital protective relay for interconnection. The developed protective relay includes protective elements required by KEPCO at the interconnection point.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 제39회 하계학술대회
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• pp.717-718
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• 2008

We developed the protection program for the generator fault protection system and each module of the digital protective relay H/W for loading the protection program. The protective algorithm for the generator is 51, 51G/N, 46P/N, 47P/N, 50G/N, and 32, and we developed each fault protection program. And we must design high efficiency microprocessor, CT, and PT for realtime measuring, relaying and high accuracy of measurement, also. From now on digital protective relay must be operated with integrated management systems. For this point, we must load various industrial protocol on the digital protective relay. In this research, we developed each protective relay H/W module according to above conditions. And we designed real-time operating system in order that each protective algorithm is operated with realtime processing on the H/W system.

• 조명전기설비학회논문지
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• 제17권6호
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• pp.39-46
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• 2003

본 논문에서는 디지털화 경향에 맞추어 변압기를 보호함과 아울러 감시 및 계측 등의 기능을 갖춘 변압기용 디지털 보호계전기를 개발하기 위한 하드웨어 및 실시간 처리가 가능한 소프트웨어의 구현 방법 등을 제시하였다. 특히 보호계전기의 모든 알고리즘 및 보조 프로그램들이 단일 프로세서에 의해 실시간으로 수행될 수 있도록 DSP의 DMA 제어기를 이용하여 아날로그 입력 데이터를 처리하였다. 아울러 비휘발성 메모리 (EEPROM, flash memory)에 보호계전 알고리즘의 수행에 필요한 각종 설정치, 이벤트 및 고장데이터를 저장하고 UART를 이용하여 데이터를 분석할 수 있도록 하였다. 그리고 시험용 변압기용 디지털 보호계전기를 제작하여 일본 NF 사의 보호계전기 시험기를 이용하여 변압기 보호기능 및 동작특성을 시험하여 그 성능을 입증하였다.

• 대한전기학회논문지:전력기술부문A
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• 제52권12호
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• pp.675-683
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• 2003

This paper describes the correction strategy of an overcurrent relay applied in the linked line for interconnecting wind farm with utility power networks in order to improve the capability of a fault detection. The fault current measured in a relaying point might vary according to the fault conditions. Generally, the current of the line to line fault or the line to ground fault in the linked line is much higher than the set value of protective relay due to the large fault level. However, when the high impedance fault occurs in the linked line, we can't detect it by conventional set value because its fault level may be lower than the generating capacity of wind farm. And, the protective relay with conventional set value may generate a trip signal for the insertion of wind turbine generators due to the large transient characteristics. In order to solve above problems and improve protective relaying algorithms applied in the linked line, we propose a new correction strategy of the protective relay in the linked line. The presented method can detect the high impedance fault which can't be detected by conventional relay set value and may prevent the mis-operation of protective relay caused by the insertion of wind farm.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 제39회 하계학술대회
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• pp.161-162
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• 2008

The steady state performance test for the digital protective relay using general relay test equipment has been main test methods. Because of the development of advanced power system testing equipments, dynamic performance test has been carried out additionally using a digital simulator such as RTDS(Real Time Digital Simulator). For the case of newly adopted digital protective relay with IEC 61850 and network, performance testing items need supplementing. This report displays testing items change according to newly protective relay.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 하계학술대회 논문집 B
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• pp.854-856
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• 2004

Electro mechanical type protective relay have an influence on the characteristics of the operation due to the change of coil impedance in accordance with the change of the temperature. We found out through an electrical test how many characteric changes are made when we change the temperature according to the types of protective relay. The result is that the protective relay operated by vactor is influenced by temperature.

• 대한전기학회논문지:전력기술부문A
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• 제52권8호
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• pp.437-443
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• 2003

In this paper an expert system is developed to decide the resetting area of protective devices in power transmission systems. A configuration change in power transmission networks from a substation extension such as new line or bus addition need resetting of protective devices around the point of configuration changes. To find the resetting area in complex power system is very difficult, especially when the distance protective relays are considered to be reset. The proposed expert system, in this paper to find the resetting area has many rules based on the changes of fault currents and apparent factors from the power system alteration. It solves the problem to find relay resetting area using the network information in the database and the rule-base. The case study shows a result of the problem to find relay resetting area in KEPCO system when there is any configuration change.