Calculation of the space charge distribution in poled soda-lime glass

An analytical model of electric field assisted diffusion of ions into a multi-component glass is extended to calculate the space charge that forms between the poled layer and the potassium peak in a poled soda-lime glass. The model is compared with numerical solutions to the drift-diffusion equations and Poisson’s equation and shows good agreement. Some recent experimental results in corona poled soda-lime glass are also discussed using this model.

Aging Characteristics of Transformer Oil-Impregnated Insulation Paper Based on Trap Parameters

Oil-impregnated insulation paper is an important part of transformers; its performance seriously affects the life of power equipment. It is of significance to study the aging characteristics and mechanism of oil-impregnated insulation paper under thermal stress for transformer status detection and evaluation. In the work, the accelerated thermal aging was carried out at 120 °C, and DP1490, DP787, and DP311 samples were selected to represent the new, mid-aging, and late-aging status of the transformer, respectively. The space charge distribution within the specimens was measured by the pulsed electro-acoustic (PEA) method and the trap parameters were extracted based on the measurement curves. Further, the aging mechanism was studied by molecular simulation technology. A typical molecular chain defect model was constructed to study the motion of cellulose molecules under thermal stress. The experimental results show that the corresponding trap energy levels are 0.54 eV, 0.73 eV, and 0.92 eV for the new specimen, the mid-aging specimen, and the late aging specimen, respectively. The simulation results show that the trapped energy at the beginning of aging is mainly determined by the loss of H atoms. The changes in trap energy in the middle stage of aging are mainly caused by the absence of some C atoms, and the trap energy level at the end of aging is mainly caused by the breakage of chemical bonds. This study is of great significance to reveal the aging mechanism of oil-impregnated insulation paper and the modification of insulation paper.

Influence of Solid TAIC on Crosslinking LLDPE by Electron Beam Radiation

In this work, solid triallyl isocyanurate (TAIC) has been fabricated and used as the crosslinking sensitizer for linear low density polyethylene (LLDPE) crosslinking application. First, 0 phr, 1.5 phr, 3.0 phr, 4.5 phr and 6.0 phr solid TAIC have been added into the LLDPE to study the radiation crosslinking results. The resulting samples are measured by X-ray diffraction (XRD), scanning electron microscopy (SEM), differential scanning calorimetry (DSC), etc. The results reveal that the crystallinity, melt point, elongation and volume resistivity decrease when the content of solid TAIC increases in LLDPE from 0 phr to 6.0 phr. However, adding a proper amount of solid TAIC (3.0 phr) can improve the crosslinking degree and tensile strength of LLDPE. Finally, the space charge distribution of the samples has been measured, and the possible mechanism of solid TAIC that affects the LLDPE electrical properties is proposed.