Lightning Protection Method For 10kV Overhead Line Using MOA And Coupling Ground Wire

10kV overhead line has low voltage level,wide distribution range,high lightning strike trip rate,and less lightning protection measures.At present,most of them rely on the installation of line arresters,but the extensive use of MOA will bring a greater burden to later operation and maintenance.Therefore,it is necessary to comprehensively apply the lightning protection method to comprehensively improve its lightning resistance level.Compared with overhead ground wires,the method of adding coupled ground wires has better applicability.Based on the differentiated lightning protection strategy of distribution lines,this thesis proposes that the method of adding coupled ground wires and line arresters to improve the lightning resistance level of distribution lines with high lightning trip rate is proposed.In order to verify the applicability of the coupled ground wire in the 10kV overhead line,the lightning protection mechanism of the coupled ground wire in the 10kV overhead line was firstly analyzed,and the clearance distance,the specific installation method and the erection number of the coupled ground wire were calculated.Under the condition of tower and line type,only one coupling ground wire should be installed,which should be hung 4.2m directly below the cross arm of bare conductors and 5.3m below the cross arm of insulated wires.Using ATP-EMTP,the models of single-circuit triangular arrangement and double-circuit linear arrangement were built respectively,and the effect of coupled ground wire on the lightning resistance level of 10kV overhead bare conductors and insulated conductors under the action of direct lightning strike and induction lightning was calculated.The results show that for bare conductors,the lightning resistance level of counterattack and induction lightning can be increased by 36.2%-86.3%after the coupled ground wire is installed,and the lightning resistance level of lightning-strike conductors can be increased by 4%-13.6%.For insulated wires,the lightning resistance level of counterattack and induction lightning can be increased by 44.7%-112.7%,and the lightning resistance level of lightning strike wire can be increased by 7%-13.6%.It is also found that the higher the grounding resistance of the tower,the more obvious the improvement effect of the coupled ground wire on the lightning resistance level of the line when induced lightning and lightning strike the cross arm.The installation coupling ground wire has the characteristics of good adaptability,obvious effect and maintenance-free,and is an important lightning protection measure for 10kV overhead lines.However,the calculation also found that erecting the coupling ground wire alone could not improve the lightning resistance level of the direct strike line,and the segment of the coupling ground wire did not improve the lightning resistance level of the line.Therefore,this thesis proposes a lightning protection method for 10kV overhead distribution line using MOA and coupled ground wire.Through simulation calculation,it is found that MOA is installed on the highest phase and one side phase of 10kV overhead distribution line,and when installed on the left and right bases,it still has the best direct lightning protection effect without additional resistance reduction measures of towers.Used in conjunction with the coupled ground wire,it can comprehensively improve the lightning resistance level of the line and has better technical economy.Under the action of lightning strike tower and induction lightning,when the coupling ground wire is segmented with 3 bases and within the tower,it is recommended to install MOA on the highest phase and one side phase of the step-by-step tower at the segment interval(including 2 ends).When the segment interval is more than 3 bases,it is a better choice to install a three-phase MOA at the same time in the step-by-step tower with the segment interval.The results obtained in this thesis provide a new method guide for lightning protection of 10kV overhead lines,and comprehensively improve the lightning resistance level of 10kV overhead lines.