| 10kV distribution line is the key link to transmit electricity to the users.Ensuring the safe and stable operation of distribution lines is the goal pursued by the electric power industry.Due to the complex structure of the distribution network and the huge volume of the network,the reliability of the distribution equipment is reduced by the damage of the distribution equipment,in which the lightning strike leads to a large proportion of the equipment damage.Special needle for lOkV overhead line,which is caused by lightning strike and broken line,brings great challenge to the safe and stable operation of distribution network.Therefore,it is of great significance to study the lightning strike of lOkV distribution overhead lines and how to effectively improve the lightning protection level of the lines.This paper takes the 10kV distribution line in Dongying District of Shandong Province as the research object.Aiming at the lightning damage and typical cases in the actual operation of the 10kV distribution network,the lightning location system is used to collect the related lightning parameters,and then the lightning protection status of the lOkV distribution network in Dongying is comprehensively analyzed,and the lightning risk level in different regions is analyzed.According to the various equipment parameters on the lOkV overhead line,through the electromagnetic transient simulation program ATP-EMTP,the simulation calculation model of Lightning Overvoltage in the typical overhead line of Dongying city is set up,the lightning overvoltage level of the lOkV overhead insulated line is studied,the factors affecting the lightning resistance level of the line are analyzed,and the lightning overvoltage and induction are compared by comparing the lightning overvoltage and induction.Under the action of lightning overvoltage,the effect of different lightning protection measures on the lightning protection level of the line will further guide the design of lightning protection alteration for Dongying line.The analysis results show that the lightning density of Dongying suburb and Kenli region is the highest,reaching 5.00-7.98 times/km2 a,and the trend of lightning with seasonal distribution is obvious,and Dongying city is divided into 5 different lightning risk areas,of which Yongan town and Dong Xi Zhen are the highest lightning strike risk areas.Through the simulation of the typical overhead line of lOkV,it is found that the lightning resistance increases with the decrease of grounding resistance.The lightning arrester can increase the lightning resistance by nearly 10 times,and the insulators with high insulation level or the long flashover arc also help to improve the lightning resistance.The lightning break line is mainly caused by the thermal stress and the electrical stress caused by the arc root of the line.By installing the arcing line and strengthening the mechanical strength of the line,the line breaking rate is reduced.The insulation level of the line can be effectively improved by increasing the number of insulators,replacing the insulated transverse load and adding the insulating layer locally;the best distance of the lightning arrester for the installation line is 3 base towers.At the same time,the switch configuration of the arrester should be paid attention to,and the adjustable clearance device can play a good protective effect on the line and line equipment,generally set in the negative.The load side is adjusted according to the insulation level of the line,and the scheme to reduce the grounding resistance is to carry out the platform type grounding transformation and local application of drag reducing agent. |
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