Space Charge Characteristics of Oil-paper under AC/DC Composite Voltage

Zhou, Yi; Huang, Xin; Zhang, Ling; Zhang, Yunxiao; Zhou, Zhongliu; Chen, Teng; Li, Xue; Huang, Meng

doi:10.1109/ceidp49254.2020.9437530

Cited by 1 publication

(1 citation statement)

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“…This is the key reason for breakdown in the insulating dielectric, flashover along the surface, and accelerated aging. At present, research on the insulation characteristics of oil-paper insulation systems focuses on partial discharge (PD) and space/interface charge characteristics under the action of electric field, temperature, moisture, and other parameters. − From the previous studies on the oil-paper insulation system, the researchers have mostly focused on the charge distribution of the oil-paper insulation system. Several studies are found whose key attention is on the test method measurement under a uniform/slightly uneven electric field.…”

Section: Introductionmentioning

confidence: 99%

Calculation of Charge Transport Phenomena and Mobility Analysis in the Insulating Oil Using First Principle and Marcus Theory

Chen,

Liu,

Maharana

et al. 2024

J. Phys. Chem. B

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Oil-paper insulation is widely used as a reliable composite insulation system in power transformers. The dielectric property of oil insulation plays an important role in the reliable operation of power equipment. To recognize the charge transfer process in composite insulation, the mobility of the charge in aged insulating oil is studied. However, few studies have been conducted on the microscopic mechanism of charge transport phenomena at the molecular level. In this research, we have studied the molecular electronic structure and the distribution of holes and electrons in the insulating oil by first-principles calculation. By combining with Marcus theory, the corresponding electron coupling energy, reorganization energy, and free energy are obtained. The corresponding charge hopping model is chosen by the parameter relation, and the hopping rate is calculated. At last, the mobility of holes and electrons in insulating oil within the insulation is simulated by the Monte Carlo method. Other possible charge migration methods are also studied and discussed for the comparison. It is observed that the transfer integral of electrons is 2 orders of magnitude larger than that of holes, which is mostly due to the localization of lowest unoccupied molecular orbitals (LUMO). The hole and charge transfers accord with Marcus hopping, the adiabatic charge transfer model, and the charge hopping rate is obtained. The actual free energy action under an external electric field is obtained by calculating polarizability and permittivity. Monte Carlo simulation is used to obtain the charge transfer image and mobility under an actual electric field. Possible types of traps and mobility of ions and clusters in the insulating oil are also studied.

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