Study On Computation Methods Of Windage Of Suspension Insulator Strings Under Dynamic Wind Loads

Flashovers caused by windage of suspension insulator strings of high voltage transmission lines frequently happened in recent years, which lead to great damages and economic loss. The research on the computation methods of windage has great practical significance in engineering.The traditional computation methods of windage are based on statics, and are unavailable to analyze the dynamic effect of wind loads. To overcome this drawback and take into account the dynamic and random effect of wind loads, some typical curves of wind load with respect to time are numerically simulated with Monte Carlo method firstly. Two numerical models, based on the finite element method and multi-rigid-body dynamic method, are then set up to analyze the windage of suspension insulator strings under dynamic wind loads with the ABAQUS software. With these two models, the dynamic responses, i.e. the wandages, of two typical suspension insulator strings of 220-kV and 500-kV transmission lines are respectively analyzed. Furthermore the friction effect between two connected insulators is analyzed with the multi-rigid-body model, and an experiment was finally set up to demonstrate the efficiency of the numerical analysis methods presented in this thesis.It is observed that the wandages of the suspension insulator strings determined with the finite element and multi-rigid-body models are consistent with those obtained by menas of the traditional method, in the case of steady wind loads. However, when the dynamic effect of wind load is taken into accout, the widages of the insulator strings determined with the finite element and multi-rigid-body models are larger than those calculated with the traditional method, which illustrates that the exclusion of the dynamic effect of wind loads in the design of transmission lines may be one of the important reasons of the frequently happened flashovers accidents. It is noted that the numerical methods presented in this thesis are verified by the experiment, which also demonstrates the friction force between two connected insulators can be neglected in the analysis of windage of insulator strings.The windages of suspension insulator strings of high voltage transmission lines...