Research On The Polymer Trap Distribution Based On Ultraviolet Absorption Spectrum And Photo Stimulated Discharge Technology

In recent years, polymer materials represented by polyethylene (PE) are widely used in power cable and high voltage electrical insulation, but due to internal structure defects and the influence from the external factors impurities in polyethylene of high voltage insulation, under the long-term effect of high electric field, high-intensity magnetic field, the chemical structure and composition of the dielectric are changed by degradation, oxidation, cross linking effect, which in turn cause electric branches and accelerate material aging, so polymer dielectric space charge problem can not be ignored. So it is particularly important to do doping modification of polyethylene and improve the aging performance.This article adopts the ultraviolet absorption spectroscopy and photo stimulated discharge (PSD) technology to test the trap energy spectrum distribution in polymer dielectric materials. Experiments show that the ultraviolet absorption spectrum and PSD is the effective tool to study the traps structure and the space charge storage and transport in polymer materials, and they are kind of non-destructive and can be used to measure the deep trap charge technology. The paper has completed the following work:Build an experiment platform to measure ultraviolet absorption spectrum at room temperature. Ultraviolet-visible spectrophotometer is used to measure the ultraviolet absorption spectrum of PE and that doped with5%MgO PE under different aging time. Experiments show that, for PE with the increasing of aging time, shallow traps gradually reduce and deep traps increase gradually, but for nano hybrid PE with the increasing of aging time, shallow traps increase gradually and deep traps reduce. The existing PSD measurement device has been improved. PSD test device is used to measure the PSD spectrum of PE and that doped with5%MgO PE under different aging time. The experiments show that for PE with the increasing of aging time, shallow traps gradually reduce and deep traps increase gradually, but for nano hybrid PE with the increasing of aging time, shallow traps increase gradually and deep traps reduce.Research shows that PE produces oxidation products such as carbonyl and hydroxyl groups in the process of aging, these free radicals can bring in deep traps. After adding impurities MgO, these free radicals conjugate with chromophore, which can inhibit the space charge injection and the ultraviolet absorption spectrum moves towards long wave, namely, shallow traps are introduced so as to achieve the purpose of improving electric field distortion in PE.