一种计及地线影响的输电线路可靠性动态评估方法

A dynamic evaluation method of transmission line reliability considering the effects of ground wire

雷击、冰灾等极端气象事件是导致输电线路故障的主要原因,输电线路的架空地线在夏季的防雷作用以及冬季更易覆冰的特点直接影响线路的可靠性水平。因此有必要研究地线对输电线路可靠性的影响及分析方法,并提出一种计及地线影响的输电线路可靠性动态评估方法。以"月份"作为时间尺度,对地线自身和输电导线逐月故障率分别统计并进行拟合。分析夏季、冬季地线状态对输电导线可靠性的影响,并引入相应的修正系数对输电导线故障率进行修正。利用全概率公式对线路停运概率进行计算,得到了与地线及导线故障率有关的线路全年逐月停运概率函数。算例验证了所提方法的可行性。

Extreme meteorological events such as lightning and ice disaster are the main reason of transmission line fault. Overhead ground wire is of lightning protection effect in summer and is easier to be iced than conductor in winter, and it directly affects the reliability of transmission line. It is necessary to study the effects of ground wire on transmission line reliability and the corresponding analysis method. This paper proposes a dynamic evaluation method of transmission line reliability which considers the effects of ground wire. ＇Month＇ is taken as time scale rather than ＇year＇ and the monthly failure rates of ground wire and conductor are respectively statistically calculated and fitted. The effects of ground wire status both in summer and winter on the reliability of transmission line are analyzed respectively, and the corresponding correction coefficients of conductor failure rate are introduced. Total probability formula is adopted to calculate the outage probability of transmission line, and the monthly outage probability function of whole year is obtained, which is related to both of the failure rate of ground wire and the failure rate of conductor. Finally, a specific sample is used to explain the method and the feasibility is verified.