Screening And Confirmatory Experimental Study Of Organic Electric Field Regulators

The development of power equipment to higher voltage level and the development of electronic devices to smaller and highly integrated direction will undoubtedly lead to the continuous improvement of the working field strength of insulation structure design,and the continuous improvement of working field strength is easy to distort the local electric field and cause the concentration of local electric field.For a long time,this will reduce the long-term operation reliability of equipment and devices.Whether electronic equipment or electronic devices,the non-uniformity of their insulation electric field will increase with the increase of working voltage level,which greatly restricts the further development of power equipment and electronic devices.How to homogenize the electric field,reduce the maximum electric field intensity in local areas and improve the insulation utilization coefficient is an urgent problem to be solved.This paper studies the organic electric field regulator that can regulate the electric field,which directly takes measures to the problem of electric field distribution homogenization.The electric field control molecules are driven by dielectric electrophoresis force to gather to the high field strength region in the uneven electric field,forming a concentration gradient distribution in the insulation,so as to effectively homogenize the electric field.Based on the existing organic electric field regulators containing benzene ring and ether bond,the effects of different functional groups on the electric field regulation ability of electric field regulators are analyzed.Five organic additives are found and divided into three categories according to their composition: containing benzene ring without ether bond,containing ether bond without benzene ring,containing benzene ring and ether bond at the same time.The organic additives were melt blended with low density polyethylene(LDPE)and hot pressed to make samples.The DC conductivity and relative dielectric constant increased with the increase of filler concentration and has high-efficiency organic electric field regulator which endows the composite material with field-enhanced conductivity characteristics.Then,the conductance curve is fitted with the theory of classical dielectric physics,the conductance mechanism of composite material is analyzed,and then the AC and DC breakdown experiment is carried out to further screen the regulator.Finally,the regulator with less negative impact on the breakdown field strength of the sample is selected for the AC electrical tree experiment after electric pre-stress treatment.The effects of these experimental conditions on the migration rate of organic electric field regulator were explored by changing the time of electric pre-stress,voltage value of electric pre-stress and temperature of electric pre-stress,and finally a comprehensive optimal regulation method was determined.The results showed that the selected organic additives with ether bond and no benzene ring had higher nonlinear conductivity,and the DC conductivity and relative dielectric constant increased with the increase of filler concentration.The conductance curve fitting shows that the conductivity curve fitting shows that the non ohmic conductivity curve of the composites containing regulators can be divided into two sections,which are consistent with the jump conductivity model,and the jump distance is inconsistent.From the fitting results,it is caused by the introduction of more carriers and charge traps by regulator.The results of AC and DC breakdown experiments show that the DC breakdown field strength of the composite material increases with the increase of filler concentration when the doping content of the two additives containing ether bond and benzene ring is lower than 1wt%,and decreases with the increase of filler concentration when it is higher than 1wt%;The AC breakdown field strength of composite dielectric increases with the increase of filler concentration,and is greater than that of pure LDPE.Finally,allyl polyoxyethylene ether(1000 molecular weight)with less negative impact on DC breakdown strength is selected as the best organic electric field regulator for further research.The experimental results of AC electrical tree experiment after electric pre-stress treatment show that the regulator migrated under the action of electric pre-stress,the ability of organic electric field regulator to inhibit AC electrical tree is the best when lower electric pre-stress is applied at higher temperature and lasts for a certain time.