Oil-paper insulation system is an important insulation structure of converter transformer. At present study, polyamic acid introduced was synthesized firstly, then perform electrospinning and thermal imidization to prepare polyimide (PI) porous fiber membrane, and the nano-SiO₂ was introduced into the fiber membrane by in-situ polymerization. FT-IR was used to characterize PI porous fiber membrane chemical structure. Consequently, when the SiO₂ addition amount is 4 wt.%, the breakdown voltage of the SiO₂/PI composite fiber reaches the maximum, which is 74 kV/mm. The dielectric constant and dielectric loss of the composite fiber film are 1.98–0.0013 (10⁷ Hz). It is worth noticing that nano-SiO₂ available in PI significantly improved its electrical performance.

油纸绝缘系统是换流变压器重要的绝缘结构。目前的研究是先合成引入的聚酰胺酸，然后进行静电纺丝和热亚胺化制备聚酰亚胺（PI）多孔纤维膜，并通过原位聚合将纳米SiO ₂引入纤维膜中。FT-IR用于表征PI多孔纤维膜的化学结构。因此，当SiO ₂添加量为4 wt.%时，SiO ₂ /PI复合纤维的击穿电压达到最大值，为74 kV/mm。复合纤维膜的介电常数和介电损耗为 1.98–0.0013 (10 ⁷  Hz)。值得注意的是，纳米SiO ₂ 在 PI 中可用的材料显着改善了其电气性能。