송전선과 배전선의 고장에 의한 voltage sag는 산업 수용가와 전력회사에 당면한 가장 중요한 전력품질(power quality) 문제들 중 하나가 되었다. voltage sag는 일반적으로 진폭과 지속시간 특성으로 기술되지만 voltage sag 현상을 규명하여 그 대책을 찾는데는 위상변위 특성을 반드시 고려해야 한다. 이 논문에서는 3상지락, 단선지락, 및 선간단락 사고가 발생하였을 경우에, 고장임피던스의 변화에 의한 voltage sag를 symmetrical components 해석을 이용하여 특성해석을 하였다. 이 때, voltage sag와 이들이 진폭과 위상에 미치는 효과를 고찰하였다. 3상지락과 같은 평형 고장은 모든 상에서 전압과 전류가 동일한 값으로 변화되고 또한 영상성분들은 영이 되었다. 그렇지만, 단선지락과 선간단락 고장과 같은 불평형 고장으로 인한 voltage sag는 진폭과 위상이 각 상마다 다르게 변화되었다. 해석결과를 확인하기 위하여 전력회로 모델들을 토대로 시뮬레이션을 수행하고 그 결과들도 검토되었다.
송전선과 배전선의 고장에 의한 voltage sag는 산업 수용가와 전력회사에 당면한 가장 중요한 전력품질(power quality) 문제들 중 하나가 되었다. voltage sag는 일반적으로 진폭과 지속시간 특성으로 기술되지만 voltage sag 현상을 규명하여 그 대책을 찾는데는 위상변위 특성을 반드시 고려해야 한다. 이 논문에서는 3상지락, 단선지락, 및 선간단락 사고가 발생하였을 경우에, 고장임피던스의 변화에 의한 voltage sag를 symmetrical components 해석을 이용하여 특성해석을 하였다. 이 때, voltage sag와 이들이 진폭과 위상에 미치는 효과를 고찰하였다. 3상지락과 같은 평형 고장은 모든 상에서 전압과 전류가 동일한 값으로 변화되고 또한 영상성분들은 영이 되었다. 그렇지만, 단선지락과 선간단락 고장과 같은 불평형 고장으로 인한 voltage sag는 진폭과 위상이 각 상마다 다르게 변화되었다. 해석결과를 확인하기 위하여 전력회로 모델들을 토대로 시뮬레이션을 수행하고 그 결과들도 검토되었다.
Voltage sags caused by line faults in transmission and distribution lines have become one of the most important power quality problems facing industrial customers and utilities. Voltage sags are normally described by characteristics of both magnitude and duration, but phase angle shifts should be ta...
Voltage sags caused by line faults in transmission and distribution lines have become one of the most important power quality problems facing industrial customers and utilities. Voltage sags are normally described by characteristics of both magnitude and duration, but phase angle shifts should be taken account in identifying sag phenomena and finding their solutions. In this paper, voltage sags due to line faults such as three phase-to-ground, single line-to-ground, and line-to-line faults are characterized by using symmetrical component analysis, for fault impedance variations. Voltage sags and their effect on the magnitude and phase angle are examined. Balanced sags of three phase-to-ground faults show that voltages and currents are changed with equivalent levels to all phases and the zero sequence components become zero. However, for unbalanced faults such as single line-to-ground and line-to-line faults, voltage sags give different magnitude variations and phase angle shifts for each phase. In order to verify the analyzed results, some simulations based on power circuit models are also discussed.
Voltage sags caused by line faults in transmission and distribution lines have become one of the most important power quality problems facing industrial customers and utilities. Voltage sags are normally described by characteristics of both magnitude and duration, but phase angle shifts should be taken account in identifying sag phenomena and finding their solutions. In this paper, voltage sags due to line faults such as three phase-to-ground, single line-to-ground, and line-to-line faults are characterized by using symmetrical component analysis, for fault impedance variations. Voltage sags and their effect on the magnitude and phase angle are examined. Balanced sags of three phase-to-ground faults show that voltages and currents are changed with equivalent levels to all phases and the zero sequence components become zero. However, for unbalanced faults such as single line-to-ground and line-to-line faults, voltage sags give different magnitude variations and phase angle shifts for each phase. In order to verify the analyzed results, some simulations based on power circuit models are also discussed.
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가설 설정
In Fig. 12(a), magnitudes and 血se angles of the phase-b and c voltages vary with different values but the jiiase-a voltage remains unchanged. For &=0Q, Vb= Vc(points, q' and rO and they have magnitudes, \/2Va and liiase angles, -180o.
제안 방법
mal-operation or failure. In this research, voltage sags caused by balanced and unbalanced faults such as three phase-to-ground, single line-to-ground, and line-to-line faults are characterized using symmetrical components analysis. Magnitucfe variation and phase angle shift of voltage sag are analyzed in detail for fault inpedance variation.
Voltage sags are usually ddmnired by system componaits such as transformers, line iiwedance, load characteristic, and fault inpedance, however, in this research, any influence of fault iirpedance on voltage sag is examined under the assurrption that only the fault impedance is changed. Fig.
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