Abstract
High-frequency power transformers are conducive to the reliable grid connection of distributed energy sources. Polyimide is often used for the coating insulation of high-frequency power transformers. However, creeping discharge will cause insulation failure, therefore, it is necessary to use disiloxane for the purpose of modifying the molecular structure of polyimide. This paper not only introduces 1,3-bis(3-aminopropyl)-1,1,3,3-tetramethyldisiloxane (GAPD) with a molar content of 1%, 2%, and 5% to polyimide, but also tests both the physical and chemical properties of the modified film and the high frequency creeping dielectric strength. The results show that after adding GAPD, the overall functional groups of the material do not change, at the same time the transfer complexation of intermolecular charge and the absorption of ultraviolet light increase. There is no phase separation of the material and the structure is more regular and ordered, moreover the crystallinity increases. The overall dielectric constant and the dielectric loss tangent value show different trends, which means that the former value increases, while the latter value decreases. In addition, the resistivity of the surface and the volume increase, which is the same as the glass transition temperature. The mechanical properties are excellent, and the strength of bulk breakdown is mounting. The insulation strength of the high frequency creeping surface has been improved, which will increase with larger contents of GAPD. Among them, the relative change of the creeping flashover voltage is not obvious, and the creeping discharge life of G5 is 4.77 times that of G0. Further analysis shows that the silicon-oxygen chain links of the modified film forms a uniformly dispersed Si-O-Si network in the matrix through chemical bonds and charge transfer complexation. Once the outer matrix is destroyed, it will produce dispersed flocculent inorganic particles which have the role of protecting the inner material and improving the performance of the material. Combined with the ultraviolet light energy absorption, the increase of deep traps, the reduction of dielectric loss, and the improvement of thermodynamic performance, can better improve the high-frequency creeping insulation strength of polyimide film and its potential application value.
Highlights
Distributed energy has numerous advantages, such as small capacity, wide distribution, and cleanness, it optimizes the power supply performance of the power grid, its instability brings challenges to system security [1]
The dielectric strength test including surface flashover voltage and creeping discharge life is carried out, and it describes the mechanism of disiloxane modification on its high-frequency surface dielectric strength, which provides a theoretical basis and optimization direction for the modification of high-frequency transformer coating insulation materials
Polyimide is composed of an electron (diamine and, charge transfer complexation betweendonor which will affect thelink) stacking of an ele polyimide molecules
Summary
Distributed energy has numerous advantages, such as small capacity, wide distribution, and cleanness, it optimizes the power supply performance of the power grid, its instability brings challenges to system security [1]. There is a lack of research on the molecular structure of disiloxane modified polyimide, especially on the test of the high-frequency surface insulation strength of the modified film and the analysis of the influence mechanism of modifications on its dielectric strength. In this way, this paper introduces 1%, 2%, and 5% molar content of 1,3–bis (3-aminopropyl)-1,1,3,3-tetramethyldisiloxane into polyimide (GAPD) to modify its molecular structure. The dielectric strength test including surface flashover voltage and creeping discharge life is carried out, and it describes the mechanism of disiloxane modification on its high-frequency surface dielectric strength, which provides a theoretical basis and optimization direction for the modification of high-frequency transformer coating insulation materials
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
