Study On Mechanical Performance Of Main Device Terminal Of Down Lead Transmission Lines In Converter Station Under Wind Load

The UHV transmission project has developed rapidly and has achieved remarkable achievement today.The completeness of power equipment is the key to ensuring power supply,and the role of strong winds on power equipment cannot be neglected which is often the root cause of damage to power equipment.Nowadays,domestic and foreign scholars have made more achievements in the protection of transmission lines and power equipment.However,there is little research on the effect of transmission lines on the connected power equipment,but many of the power equipment connected to the transmission lines are in harsh environments,and many accidents caused huge losses have occurred,Therefore,it is of great theoretical significance and engineering guidance value to study the effect of the down lead transmission lines under wind load on the stress of the connected device terminals.In this paper,the down lead transmission lines structure of a converter station is taken as the research object,the wind load is equivalent to the static concentrated load,the mechanical performance of the main device terminal of the down lead transmission lines of the converter station under wind load is studied,7 sets of truss-down lead transmission lines system tests and 15 sets of cross-line down lead transmission lines system tests are carried out to study the mechanical performance of the down lead transmission lines main equipment terminals of the converter station under wind load.The finite element analysis method is used to study the influence of the span of cross-line,the form of the down lead transmission lines,and the angle of the string insulator on the mechanical performance of the main equipment terminals.the main conclusions are as follows:(1)Through conducting the equivalent wind load experiment of the down lead transmission lines system,it is found that when the down lead transmission lines are installed,a large installation force is generated on the stressed end of the main device terminal,which is a part that can not be ignored in the force analysis of the device terminal of the down lead transmission lines system.When the down lead transmission lines are subjected to wind load,among the components of the device terminal,the stress of the terminal rod is the largest,which is the weak part of the device terminal.(2)Through the test,it is found that the device terminal of the cross-line-down lead transmission lines system under wind load is significantly larger than that of the trussdown lead transmission lines system,indicating that when down lead transmission lines system is subjected to wind load,the effect of the cross-line on the force of the device terminal cannot be ignored,the actual project should consider the stress of the device terminal according to the cross-line-down lead transmission lines system.(3)Through the equivalent wind load test of the down lead transmission lines system,the main factors and laws affecting the stress of the main device terminal of the down lead transmission lines are found.The conclusion is that the larger the wind load,the closer the down lead point of the lead transmission lines is to the edge,the smaller the sag of the down lead transmission lines,the larger the horizontal span,and the insulator string connection is I string connection,the larger the stress on the device terminal in the down lead transmission lines.The horizontal reaction force of the device terminal of the herringbone down lead transmission lines system are larger than the single down lead transmission lines system,and the vertical reaction force and the maximum strain of the terminal rod are smaller,and the resultant force is closer.(4)Through finite element analysis,it is found that the force increases with the increase of the span of the cross-line,it is advisable to design device terminals with different strengths according to the span.As the angle of the insulator string increases,the force of the device terminal will decrease accordingly,the downward trend will be sharp first and then smooth,it is recommended that in the actual project,the angle of the insulator string is set to more than 20 degrees.Compared with the single-lead down transmission lines system,the device terminal of the II-shaped down transmission lines system have less stress,and the force change of the terminal rod is not obvious.The device terminal of the II-shaped down lead transmission lines system have a smaller horizontal reaction force than the herringbone down lead transmission lines system,and the vertical reaction force and the stress of the terminal rod are larger,it is advisable to design device terminals according to the form of the down lead transmission lines.