Study On Deterioration Analysis And Test Method Of UHV Large Tonnage Disk-suspended Porcelain Insulators

In this paper,we analyzed the overall porcelain insulator,porcelain parts and cement cement from the product structure level,sorted out the key parameters affecting the performance of porcelain insulator porcelain parts and cement cement,analyzed the causes of product deterioration,and optimized the design of the electrical test breakdown method for porcelain parts in a UHV project.Volume resistance,electromechanical breaking load test and hot machine test were carried out on intact porcelain insulator products of a manufacturer extracted from the operation site,and it was found that insulators running for 3～5 years and the spare parts of the same period all showed a significant decrease in electromechanical performance,and there was still a possibility of continuous deterioration.The results show that the Al2O3 content,porosity and porous shape of porcelain parts can directly affect the strength of porcelain parts,while the porosity and microscopic crystal phase distribution can evaluate the long-term stability of porcelain parts.The Al2O3 content of the porcelain parts of deteriorated porcelain insulator manufacturers is only 45.3%,the porosity of gray glaze is 9.7%,the porosity of brown glaze is as high as 10.1%,the porosity is poor,more narrow,penetrating porosity,the crystalline structure of corundum particles covered with holes,and more large size quartz particles and feldspar remains,the quality of porcelain parts is poor.Carried out a multi-manufacturer cement cement performance test research to explore the long-term performance changes of the cement cement,analysis of cement cement key control factors,and to evaluate the performance of cement cement,the results show that the cement cement cement compressive,flexural strength directly affects the cement cement working performance,dry shrinkage rate and elastic modulus,more influence the fit relationship between the parts.Detei-iorated porcelain insulator manufacturer cement cementitious compound 28 days flexural strength 16.2Mpa.compressive strength 99.3Mpa,dry shrinkage rate 0.070%.compared with other manufacturers are in the normal level,but the elastic modulus is 34.04Gpa,can not pass the hot machine test,and porcelain parts strength match poorly.Cement cement with time changes volume shrinkage,cone head products adhesive thickness up and down a large gap,shrinkage is different resulting in stress distribution changes,so that cement cement,porcelain parts local stress is too concentrated,when the cement freeze-thaw expansion,local stress further increase,and porcelain parts strength is not enough,the mechanical properties of the parts do not match,internal defects are magnified,after experiencing long-term operation,cracks gradually expand,resulting in the emergence of umbrella disc After long-term operation,the cracks gradually expand,leading to the emergence of the umbrella plate or head cracking,and the insulator produces zero value.In order to test the electrical strength of porcelain parts that have been put on the network,and to better reflect the actual level of electrical strength of porcelain parts,the electrical strength breakdown method in the original standard is optimized by means of wire-cut sampling and the use of large-diameter oval angle flat electrode,which reduces the difficulty of sample making and has better generality,and the 2mm thickness of porcelain parts can be broken down in the middle part.