TY - JOUR
T1 - Mechanism study of the conductivity characteristics of cellulose electrical insulation influenced by moisture
AU - Zhao, Haoxiang
AU - Mu, Haibao
AU - Zhang, Daning
AU - Baumeier, Björn
AU - Yao, Huanmin
AU - Guo, Guangzhi
AU - Zhang, Guanjun
N1 - Funding Information:
This work was supported by the National Natural Science Foundation of China (NNSFC) (No. 52107165), 71st Postdoctoral Foundation of China (No. 2022M712511), and the Shaanxi Provincial Key R&D Program (No. 2022GY-269).
PY - 2022/12/7
Y1 - 2022/12/7
N2 - Cellulose insulating paper is widely used in the power industry for its good electrical insulating properties. Moisture sharply increases its conductivity, which directly leads to the weakening of insulation performance and greatly increases the risk of subsequent electric field distortion and insulation breakdown. This paper focuses on the microscopic mechanism of moisture changing the characteristics of charge transport in cellulose insulation and attempts to reveal the related conductivity mechanism. To achieve this purpose, microscopic and macroscopic perspectives are integrated and several simulation and experimental methods are utilized comprehensively. The molecular dynamics simulation results showed that most water molecules in damped cellulose were individually and uniformly adsorbed on the hydroxyl groups by hydrogen bond, and the quantum chemistry computation results showed that the lowest unoccupied molecular orbital more appeared on the water molecule and the corresponding density of state increased. Then, experimentally, it was confirmed that the trap energy level decreased by the thermally stimulated current method. On this basis, the promotion effect of moisture on charge transport is predicted and verified by polarization and depolarization current methods. As the moisture content increased, more charge carriers escaped from the trap by hopping and participated in long-range continuous charge motion. Therefore, after dampness, the current of cellulose insulating paper increased exponentially with the increase in electric field strength, which was consistent with the hopping conductivity mechanism.
AB - Cellulose insulating paper is widely used in the power industry for its good electrical insulating properties. Moisture sharply increases its conductivity, which directly leads to the weakening of insulation performance and greatly increases the risk of subsequent electric field distortion and insulation breakdown. This paper focuses on the microscopic mechanism of moisture changing the characteristics of charge transport in cellulose insulation and attempts to reveal the related conductivity mechanism. To achieve this purpose, microscopic and macroscopic perspectives are integrated and several simulation and experimental methods are utilized comprehensively. The molecular dynamics simulation results showed that most water molecules in damped cellulose were individually and uniformly adsorbed on the hydroxyl groups by hydrogen bond, and the quantum chemistry computation results showed that the lowest unoccupied molecular orbital more appeared on the water molecule and the corresponding density of state increased. Then, experimentally, it was confirmed that the trap energy level decreased by the thermally stimulated current method. On this basis, the promotion effect of moisture on charge transport is predicted and verified by polarization and depolarization current methods. As the moisture content increased, more charge carriers escaped from the trap by hopping and participated in long-range continuous charge motion. Therefore, after dampness, the current of cellulose insulating paper increased exponentially with the increase in electric field strength, which was consistent with the hopping conductivity mechanism.
UR - http://www.scopus.com/inward/record.url?scp=85144271342&partnerID=8YFLogxK
U2 - 10.1063/5.0121978
DO - 10.1063/5.0121978
M3 - Article
AN - SCOPUS:85144271342
SN - 0021-8979
VL - 132
JO - Journal of Applied Physics
JF - Journal of Applied Physics
IS - 21
M1 - 215104
ER -