Study On The Hydrophobicity Of Epoxy Resin Materials

In recent years,epoxy resins have been widely used as insulating materials in high voltage equipments for power transmission and distribution systems.Epoxy resin systems are quite mature in indoor insulation applications.However,as for outdoor conditions,epoxy resins must withstand the effects of electrical and severe weather,as well as the inevitable UV radiation.Although alicyclic epoxy resin materials have excellent weather resistance,compared with mature silicone rubber insulation materials,it is still necessary to investigate hydrophobicity,hydrophobicity after surface contamination,and tracking resistance.Under the actual power system operating environment,due to the influence of wet weather,even if the structural design of the composite insulator is reasonable and excellent,corona discharge will inevitably occur.The long-term exposure of the composite insulator material to the surface of the corona environment will reduce the water repellency and affect its insulation properties.Therefore,this thesis establishes a set of needle plate electrode AC corona aging test device to simulate the corona discharge in the natural environment and understand how the aluminum hydroxide filler affects the hydrophobicity and hydrophobicity of the alicyclic epoxy resin matrix.A sample of the aluminum hydroxide micro-composite was placed between the needle plate electrodes in direct contact with the planar ground electrode,but it was separated from the needle electrode by adjusting the air gap spacing.The change in the hydrophobicity of the test sample with the corona discharge time was determined by measuring the static contact angle of water with the JC2000DM contact angle meter.In this study,five kinds of aluminum hydroxide/alicyclic epoxy resin materials were prepared.The mass fraction of aluminum hydroxide is 0 wt%,3 wt%,7 wt%,10 wt%,15 wt%,respectively.This paper mainly studies the hydrophobic loss and recovery law of AC corona on the influence of different corona continuous discharge time,the effect of different corona voltage on the hydrophobicity of cycloaliphatic epoxy resin,the effect of high and low temperature on the recovery characteristics of hydrophobicity of alicyclic epoxy resin,the effect of different salt density and gray density on migration characteristics of hydrophobic water,the influence of ambient temperature and humidity on migration characteristics of hydrophobic water and tracking resistance.The results show that the hydrophobicity of the five alicyclic epoxy resin materials is not obvious when the corona duration is short.When the corona time is too long,such as more than 72h,only ATH10 and ATH15 can restore water repellency;The increase of the amplitude of the corona voltage applied to the surface of the alicyclic epoxy resin sample will increase the degree of hydrophobic loss on the surface of the sample;the temperature has a great influence on the recovery process of the alicyclic epoxy resin sample after corona,high temperature environment can help to improve the hydrophobic recovery rate of the sample after corona,and the static contact angle of the alicyclic epoxy resin sample can not be restored to the initial state in the low temperature environment;the salt density and the gray density increase both contribute to the hydrophobic migration process,but the degree of influence of salt density is not as obvious as gray density;as the amount of ATH doping increases,the time required for the static contact angle of the alicyclic epoxy resin sample to return to stability becomes shorter and shorter;The alicyclic epoxy resin sample has little effect on the hydrophobic migration process;the doped ATH particles can slow down the electrical erosion process of the alicyclic epoxy resin sample and prolong the surface trace penetration time of the sample.