Disturbance Detection Of Atmospheric Overvoltage And Study On Its Suppression Measures

Weather is one of the causes of Distribution line fault tripping according to analysis on running situation of power Distribution lines of Shandong Power Grid in recent years. More than half of Distribution lines faults were caused by lightning stroke and tripping caused by lighting stroke reached above 80% in the southern mountainous area of western Shandong province in recent three years. Fault tripping of Distribution lines caused by lightning stroke accounted for 60% among various causes of Zibo Power Grid in 2015. The lower the voltage class, the higher rate of fault tripping caused by lighting will be. Frequencies of line tripping caused by lighting stroke is inversely proportional to the voltage class of lines through analyzing running situation. Zibo has the large proportion of the grid lines old, and disqualified situation of grounding electrode resistance should be sorted and rectified. most of these old lines are cross high-speed rail, highway, road and densely populated areas, which have entered into an accelerated aging and high-accident period. It occurred frequently that power Distribution lines were damaged by external forces, which have become a main factor influencing safe operation of the power grid.Change rule of various electrical quantities has been analyzed and studied in the process of Distribution line fault process. S converter technique has been employed to analyze features in the transient process, to analyze and extract the transient characteristics in the process of Distribution line overvoltage. At the same time, in order to improve work efficiency, it has also analyzed harmonic characteristic in the transient waveform and have conducted research on disturbance identification of voltage waveform. Different types of waveform characteristics in transient state have been extracted and analyzed; Amplitude and frequency features of disturbance signals have been identified and studied through S converter method, so as to improve reliability of power supply system. Use of the method can effectively reduce the staff workload, improve reliability of power supply system, ensuring safe and reliable operation of distribution lines.In order to suppress disturbance of overvoltage intruding wave and reduce influences of overvoltage intruding wave on power distribution network, new reliable and stable overhead insulated lines with lightning strike protection measures, i.e., built- in column- type voltage limiter has been operated in network on trial in lighting area of Ezhuang, Zibo, according to the characteristics of the distribution network lines and lightning activity characteristics in Zibo area, which can provide solutions for overhead insulated lines intruded by atmospheric overvoltage in power distribution network, ensuring safe and reliable operation of power grid.