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EMTP를 이용한 태양광 발전의 계통 연계시 고조파 분석에 관한 연구
고윤태(Yun-Tae Ko),서훈철(Hun-Chul Seo),여상민(Sang-Min Yeo),김철환(Chul-wan Kim) 대한전기학회 2008 대한전기학회 학술대회 논문집 Vol.2008 No.11
태양광 발전은 영구적이고 친환경적인 에너지를 생산하는 에너지원으로서 세계적인 관심을 받고 있으며 앞으로도 더 많은 투자와 연구가 진행될 것으로 예상된다. 이러한 태양광 발전이 계통에 연계되었을 때 전력품질, 보호 등 다양한 문제에 영향을 끼친다. 특히, 태양광의 출력을 직류에서 교류로 변환하는 인버터의 스위칭으로 인하여 많은 고조파가 발생하게 된다. 따라서, 태양광 발전의 계통 연계시 발생하는 고조파의 분석은 반드시 필요한 사항이다. 본 논문에서는 태양광 발전의 계통 연계시 고조파 분석을 수행하였다. 태양광 발전은 EMTP를 이용하여 단상 풀 브릿지 인버터를 이용하여 계통에 연결되는 것으로 모델링 하였다. 태양광 발전의 용량 및 비선형 부하의 용량을 다양하게 변화시켜 모의 하였으며, 다양한 조건에 따라 부하에 흐르는 전류의 THD의 변화를 분석하였다.
초전도 한류기를 고려한 재폐로 차단기 동작 scheme 개발
고윤태(Yun-Tae Ko),서훈철(Hun-Chul Seo),이상봉(Sang-Bong Rhee),김철환(Chul-Hwan Kim),김재철(Jae-Chul Kim),현옥배(Ok-Bae Hyun) 대한전기학회 2009 대한전기학회 학술대회 논문집 Vol.2009 No.7
This paper proposes the new reclosing scheme considering the recovery time of SFCL in distribution systems which is based on variable dead time control. The main idea is that it uses the carrier signal to distinguish whether the fault is instantaneous or permanent following initial recloser opening. The system and SFCL is modeled by using Electromagnetic Transient Program(EMTP) and the validity of the reclosing scheme represented in this paper is analyzed according to the value of the fault resistance and the time of the fault removal.
Carrier 신호를 이용한 배전계통의 새로운 재폐로 방식
고윤태(Yun-Tae Ko),서훈철(Hun-Chul Seo),이상봉(Sang-Bong Rhee),김철환(Chul-Hwan Kim),김재철(Jae-Chul Kim),현옥배(Ok-Bae Hyun) 대한전기학회 2009 전기학회논문지 Vol.58 No.11
This paper proposes the new reclosing scheme considering the recovery time of SFCL in distribution systems which is based on variable dead time control. The main idea is that it uses the carrier signal to distinguish whether the fault is instantaneous or permanent after tripping the line by recloser. The system and SFCL is modeled by using Electromagnetic Transient Program(EMTP) and the validity of the reclosing scheme presented in this paper is analyzed according to the fault resistance, the recovery time of SFCL and the fault clearing time.
제어 가능한 전류원 기반의 인버터를 이용한 실제적 태양광 발전 시스템 모델링
오윤식(Yun-Sik Oh),조규정(Kyu-Jung Cho),김민성(Min-Sung Kim),김지수(Ji-Soo Kim),강성범(Sung-Bum Kang),김철환(Chul-Hwan Kim),이유진(You-Jin Lee),고윤태(Yun-Tae Ko) 대한전기학회 2016 전기학회논문지 Vol.65 No.8
Utilization of Distributed Generations (DGs) using Renewable Energy Sources (RESs) has been constantly increasing as they provide a lot of environmental, economic merits. In spite of these merits, some problems with respect to voltage profile, protection and its coordination system due to reverse power flow could happen. In order to analyze and solve the problems, accurate modeling of DG systems should be preceded as a fundamental research task. In this paper, we present a PhotoVoltaic (PV) generation system which consists of practical PV cells with series and parallel resistor and an inverter for interconnection with a main distribution system. The inverter is based on controllable current source which is capable of controlling power factors, active and reactive powers within a certain limit related to amount of PV generation. To verify performance of the model, a distribution system based on actual data is modeled by using ElectroMagnetic Transient Program (EMTP) software. Computer simulations according to various conditions are also performed and it is shown from simulation results that the model presented is very effective to study DG-related researches.
분산전원 연계 계통에 초전도한류기 적용 시 보호협조 분석
서훈철(Hun-Chul Seo),고윤태(Yun-Tae Ko),이상봉(Sang-Bong Rhee),김철환(Chul-Hwan Kim),김재철(Jae-Chul Kim),현옥배(Ok-Bae Hyun) 대한전기학회 2009 대한전기학회 학술대회 논문집 Vol.2009 No.7
The increasing of fault current by introducing of the distributed generation(DG) in distribution system disrupts the protective coordination. Therefore, this paper applies the superconducting fault current limiter(SFCL) to solve this problem. The distribution system with DG and SFCL is modeled by EMTP. According to various size of the DG, the fault is simulated and the operating time of overcurrent relay is investigated accoring to the resistance of SFCL.
태양광발전 연계계통에서 3상 단락 고장 시 고장위치 및 고장저항 추정기법
심형욱(Hyung-Wook Shim),고윤태(Yun-Tae Ko),이상봉(Sang-Bong Lee),김철환(Chul-Hwan Kim) 대한전기학회 2009 대한전기학회 학술대회 논문집 Vol.2009 No.11
Renewable energy, wind power, fuel cell photovoltaic, tidal energy and etc, have been introduced to distributed generation. Distributed generation connected with utility grid has been influenced on flicker, harmonic by voltage settlement, voltage fluctuation and islanding of distributed generation at faults. Therefore distinction of faults and estimation of fault location and resistance exactly is very important for the efficient of distribution protection. This paper suggests a new method for distinguishing faults and estimating a fault location and fault resistance concerning three phase fault. All cases were executed and verified by simulation using EMTP/ATPDraw. This method was proven both accuracy and reliability of the simulated model system.
이상봉(Sang-Bong Rhee),김철환(Chul-Hwan Kim),서훈철(Hun-Chul Seo),고윤태(Yun-Tae Ko),김규호(Kyu-Ho Kim),김재철(Jae-Chul Kim),현옥배(Ok-Bae Hyun) 대한전기학회 2009 대한전기학회 학술대회 논문집 Vol.2009 No.7
This paper presents a asymmetry fault current reduction scheme with recloser operation during transient period. The principle of asymmetry current nature is reviewed and asymmetry components reduction with recloser operation is explained. Throughout the simulation, results verifies the proposed scheme for recloser operation and its effectiveness.
Positive Offset Mho 계자 상실 계전기 보호 협조 정정에 관한 연구
김광현(Kwnag-Hyun Kim),박지경(Ji-Kyung Park),김준혁(Jun-Hyeok Kim),김두웅(Doo-Ung Kim),강성범(Sung-Bum Kang),김철환(Chul-Hwan Kim),유영식(Young-Sik Lyu),양정재(Jeong-Jae Yang),고윤태(Yun-Tae Ko) 대한전기학회 2016 전기학회논문지 Vol.65 No.8
It is important to clear the fault and prevent resulting in damage to power system. Although the frequency of generator internal fault is relatively low, it can lead to incalculable damage to power system as well as generator. Especially, loss of field on generator can cause the generator to lose synchronism for a short time if it is not removed promptly. Therefore, it is needed to conduct research on loss of field relay for detecting or clearing the loss of field. However, the setting of the relay may vary in generator operator or engineer, and the relay is not coordinated well with other elements associated with loss of field. In this paper, we address specifically the coordination of positive offset mho loss of field relay which is one of the protection schemes for loss of field. Computer simulations are performed by using ElectroMagnetic Transients Program-Restructured Version (EMTP-RV) based on actual data.