Analysis On Lightning Protection Performance And Mechanical Properties Of Composite Materials Tower

Due to its metal material,the traditional tower has many problems such as insufficient insulation strength,low lightning resistance,corrosion and fracture in its long-term operation.Among them,the line trip caused by lightning is 60% of the total accident trip rate.Composite materials have good external insulation,corrosion resistance and portability.They are used as new transmission towers to overcome the above problems.Therefore,the composite material tower study on lightning protection and mechanical properties has important theoretical significance and practical value.The grounding mode is an important factor affecting the lightning resistance performance of the tower.In order to improve the lightning resistance of the composite pole and tower,a variety of grounding methods are designed and designed for the typical 110 k V composite tower.In order to simulate the overvoltage distribution of composite tower under lightning,the impact characteristics and multiwave impedance model of traditional tower under lightning stroke were studied.Based on the existing theoretical foundation and the actual situation of the engineering,the improved multi wave impedance model is proposed considering the influence of the capacitance between the wire and the grounding wire of the composite pole to the distribution of the overvoltage.The key parameters of the composite tower were extracted,and the electromagnetic transient simulation model was established.Through calculation,the lightning withstand level of different grounding modes,determine the optimal scheme.The finite element model of composite tower is established,the load under different conditions is defined,and the mechanical properties of tower are calculated and analyzed.Aiming at the location where the load is bigger,the optimization and improvement plan is put forward to ensure the safe operation of the line.The calculation results show that the maximum overvoltage under the influence of capacitance is 38% lower than that of the capacitor model,and the lightning resistance level of the single grounding method is 108 k A.Under extreme conditions,the maximum stress 860 MPa and maximum displacement 6.9cm of the tower ground wire cross section are destroyed.Under the same conditions,the stress drop is256 MPa and the maximum displacement is 3.2cm,which is normal operation.The research results show that the capacitance has a certain influence on the overvoltage division of the composite pole and tower.Using reasonable grounding mode and structural optimization measures,the lightning resistance and mechanical properties of the composite pole and tower can be maintained at a high level,and it has a good application prospect..