Research On Dynamic Characteristics And Seismic Performance Of Composite Insulator Equipment In UHV Converter Station

China’s seismic fault zones are widely distributed,with shallow focus and high intensity.A large number of earthquake damage lessons in the past have shown that the seismic reliability of power systems is poor,and it is of great practical significance to study the seismic performance of power systems.UHV composite pillar insulators,lightning arresters and other equipment are very important electrical equipment in substations and converter stations.It is easy to cause casing breakage and flange cracking under the action of earthquakes,which not only destroys its own electrical function,but also couples it.The connected equipment will cause an impact.In severe cases,the wires will be broken and the equipment destroyed.Therefore,the research on the dynamic characteristics,seismic performance and seismic strengthening measures of UHV composite electrical equipment is of great significance for maintaining the stability of the facilities in the station and improving the seismic performance of the power system.This paper analyzes the material characteristics and seismic damage characteristics of composite electrical equipment,and investigates the current status of seismic research of high-voltage electrical equipment at home and abroad.On this basis,the seismic performance of composite electrical equipment is researched.On the basis of grasping the structural type and material characteristics of the composite pillar insulator,it is proposed that the pulse excitation method or the environmental excitation method can be used to perform dynamic tests on the pillar electrical equipment,and through the on-site dynamic characteristic test,the pillar insulators,lightning arresters and other equipment are obtained.Dynamic characteristic parameters such as damping ratio and natural frequency provide basic data for subsequent research;When analyzing the damage identification of composite insulators,the bearing capacity of the flange joint should be used as the performance evaluation index of the composite insulator,and the main concern is the damage at the flange joint of the insulator.For cantilever beam structures such as composite pillar insulators,the effect of point damage on its frequency and vibration mode is analyzed,and a damage identification method based on dynamic characteristics is proposed.and two dynamic fingerprints,namely the frequency change square ratio and the curvature mode,are selected to identify the damage;Combined with the structural characteristics of the post insulator,the dynamic time history method was used to analyze the seismic response of the insulator,and the response characteristics and seismic weak links of the equipment under different earthquakes were obtained.The results show that the top displacement and root stress of the insulator under fortification and rare earthquakes are both It can meet the electrical and mechanical requirements,and the seismic reliability is high;and the influence of structural parameters such as the diameter and pitch height of the pillar insulator on its seismic performance is analyzed,and the trend of the influence of structural parameter changes on the seismic response characteristics is obtained;The effect of setting the cable on the seismic performance of the equipment was discussed,and it was confirmed that the installation of the cable can effectively improve the lateral rigidity of the equipment and greatly reduce the response of the equipment under earthquake action.The influence of stress and cable height on the seismic performance of equipment.