고장 위치법에 기반한 순간전압상승 평가 연구

Abstract

This paper covers the stochastic assessment of voltage swells based on the fault positions method. The voltage swell is one of the problems of power quality and although not as often as voltage sag does, it has been perceived as a problem affecting the operation of sensitive loads and causing various damages. The definition of voltage swell is the phenomenon as RMS voltage increase of 1.1-1.8 p.u. for 0.5 cycle to 1 minute. One major cause of voltage swell is a single line-to-ground fault which is the most common fault type in power systems. When a single line-to-ground fault occurs, the faulted phase can experience voltage drop and voltage swells occur on unfaulted phases. Generally, the voltage increase of a swell is more severe in ungrounded or delta systems. Effective countermeasures for voltage swells need to assess the trend of voltage swell occurrences at sensitive loads. Although various methods of assessing voltage sags have been introduced, there is little study on assessing voltage swells caused by faults in power system. In this paper, the assessment of voltage swells due to single line-to-ground faults was performed using the method of fault positions.