Research On Calculation Model Of Action Times Of Arrester With Fixed Gap

The installation of lightning arrester with fixed gap in the multi lightning flashover area of 110 k V and above lines can greatly improve the lightning resistance level of transmission lines and effectively reduce the number of lightning trips.When checking the operation of the arrester,it mainly judges from three aspects: the overall appearance of the arrester,the leakage current value of the arrester,and the number of action counters.In the long-term operation of the arrester,the change of its zinc oxide resistor is seldom shown on the appearance,and is not easy to be found in time.In the actual engineering maintenance of arrester with fixed gap,the leakage current cannot be measured due to the existence of gap,so it can only be detected by power failure and dismantling of a single arrester,and the operation problem of arrester cannot be found in time,which is time-consuming and laborious.The operation times of arrester counter become the main basis for reliability prediction of arrester operation.Therefore,this paper studies the calculation method of operation times of arrester with fixed gap.The main contents are as follows:First of all,this paper studies the action mechanism of the arrester with fixed gap,and analyzes the relevant factors that affect the action of the arrester based on the operation data of high-voltage transmission line,lightning location system data and the actual action times of the arrester with fixed gap provided by a power grid in recent years.Then,this paper proposes a new method to calculate the action times of arrester with fixed gap based on the lightning location system,the data of transmission line equipment account and the lightning protection mechanism.First of all,the lightning area of the line is determined by the parameters of transmission line and lightning current,and all lightning currents of the lightning area are calculated according to the installation time of lightning arrester and the data of lightning positioning system over the years;then,the lightning resistance level of the line is calculated by using the method of regulations,and the maximum and minimum lightning current value and lightning shielding rate of the line are calculated according to the improved electrical geometric model;finally,the number of actions of the arrester with fixed gap is calculated by analyzing the number of actions of the arrester caused by counterattack lightning and surrounding lightning.Finally,this paper proposes a method to calculate the number of actions of MOA with gaps based on the lightning location system,transmission line data,lightning protection mechanism and GA-BP neural network technology.First of all,calculate the maximumlightning current in the lightning area and the line lightning area;then,determine the structure of GA-BP neural network,use the trained network to judge whether the lightning arrester acts after lightning stroke,efficiently and quickly achieve the prediction of the number of lightning arrester actions.The two calculation methods proposed in this paper can accurately predict when to test the live or off-line performance of the gapped arrester and which gapped arrester can not be tested,so as to reduce the misjudgment and missed judgment of the defect detection of the arrester.This method is a non-stop,no need to dismantle,cost-effective,convenient and feasible method to identify the early defects of arresters,and effectively and reasonably uses the big data in the power grid,greatly reducing the maintenance time,saving the workload and improving the work efficiency.