Research On Integrated Lightning Protection Technology Of Distribution Network

With the rapid economic development of our country, the power load in urbanand rural is increasing, the power has more significantly improved now than past.In order to meet the needs of the growing production and the people’s livings, thepower government in china has carried out the rectification of the voltage level,expanded the power supply radius and improved the network structure of thedistribution network. But the distribution network has its own characteristics,when the line is being struck by lightning, it results in the grid equipment damageand the line tripping accidents. So the research on the lightning protectionmeasures of the distribution network in china has major engineering significance.In order to understand the actual situation of chinese distribution network,this paper conducted research on the distribution network in Qinzhou direction.And first we divided these research objects into two classifications, the one ismountainous areas and the other is coastal areas, and to collect the informationsuch as the law of lightning activities, the line insulation level, the line situationand the lightning disturbance. According to the data of the test of the groundingresistance and soil resistivity around the lines and towers, and the result of theinsulator impulse voltage test, this paper build the simulation model to analyze themain causes of the lightning disturbance in the distribution network.By analyzing, we find that the main reason for overhead distribution line’sflashover caused by lightning is not over-voltage caused by direct lightning strokebut lightning over-voltage. For the distribution line lightning emphasis should beplaced on the lightning protection. For the grid substation, it suffers lightningdamage from two ways, one is a direct lightning stroke hazards and the second isthe harm caused by the lightning invasion wave resulted in over-voltage. Inparticular, the problem about the line insulation level and the insulationcoordination of the line and substation is prominent, the distance between thelightning rod with the equipment to be protected is insufficient, the lightning rodprotection range is small, distribution equipment lightning protection measures areput in place, there are different degrees of corrosion and fracture in groundingdevice, that results in the value of grounding resistance is high, and theaggravation of three-phase load imbalance with the mode of the neutral point operation makes the distribution network have a lightning trip risk. Theabove-mentioned problems result in the severe lightning situation of Chinesedistribution network. Combined with the actual situation of the research objects,the installation of over-voltage protection devices paralleled insulators withautomatic device and installation the over-voltage protection devices in parallel tothe insulators on the incoming line with arrester protection in station, that make“mediator type” lightning as a strong complement of “plus-type” lightning,reasonable application distribution network neutral point operation mode andmonitoring three-phase load, increasing the intensity distribution networkoperation and maintenance, improving the lightning protection measures of thepower distribution equipment, that will build a systematic, comprehensive,three-dimensional lightning protection project.