Research On Charged Detection Of Faulty Insulators Based On Distribution Characteristics Of Space Electric Field

The Insulator is an important part of mechanical support and electrical connection in transmission line.Once the main body is faulty,it may cause serious faults such as broken string and insulation failure.There is a space electric field around the charged insulator.When the charged insulator is faulty,the electric field around the insulators will be partially distorted compared to the normal state.Therefore,the faulty insulator can be identified by comparing and analyzing the electric field distribution characteristics before and after the deterioration.Therefore,it is of great significance to carry out charged detection of space electric field to identify and replace the faulty insulator string in time.This paper mainly does the following three aspects:(1)The space electric field distribution characteristics of typical defects of insulator are obtained.Based on COMSOL software,a three-dimensional model of porcelain and composite insulator for 110 k V transmission line is established,and the space electric field curve under normal state is obtained.Typical defects are set up according to the data of investigation and statistics.For porcelain insulator,the defect settings are mainly zero value and low value insulator.For composite insulator,the defect settings are mainly umbrella skirt damage,sheath damage and core rod conduction.The three-dimensional model of insulator in defect state is established,and the curve of electric field distribution in different position and degree defect are obtained,and the local distortion point of electric field strength is determined.(2)The space electric field measurement system is developed,and the charged test of faulty insulator is carried out.After analyzing the measurement principle,advantages and disadvantages of the capacitive electric field sensor and the optical electric field sensor,this paper adopts Pockels photoelectric effect lithium niobate crystal as the core component,equipped with beam splitter,polarizer,optical fiber and other components of the data conversion transmission module,to build the space electric field measurement system,and to calibrate its power frequency electric field response characteristics,to achieve the ground test function.In the high voltage test hall,the charged detection test of faulty insulator is carried out,and the measured data and electric field simulation data are compared and analyzed.The results show that the measurement system can effectively determine the deterioration position and degree of insulator and verify the practicability of electric field test.(3)The miniaturization design of space electric field measurement system is realized,and the unmanned aerial vehicle(UAV)inspection platform is built.Using high integrated optical elements,a miniaturized space electric field sensor is designed,and the influence of UAV intervention on the original space electric field of insulator is analyzed.The UAV inspection platform including airborne end and ground end is built,and the electric field signal wireless transmission device based on A/D conversion module and radio frequency module is completed.The signal transmission between airborne end and ground end of electric field measurement signal of UAV inspection platform is realized.An charged test was carried out in an electric power research institute The test results show that the device can detect the defects of composite insulator and has practical engineering value.