Abstract：Electrostatic charges can be accumulated on solid dielectric surface and are for a long time are observed. It has been found that the field is seriously enhanced and surface discharge is induced. Therefore, it’s very important to investigate the behavior of surface charge. Previous works have shown that the charges are deposited on the region where normal component of electric field exists. However, knowledge of the behaviour of surface charge under the electric field with strong tangential but weak normal component is very limited. In this paper, polybutylene naphthalate (PBN) is employed as test sample. By applying a negative bias voltage between two aluminum electrodes on the surface, a field of strong tangential component is obtained. An electrostatic probe is designed to measure the charge density not only in the accumulating but also the decay processes. Obtained results show that a large amount of negative charges are deposited on the surface. The max charge density appears adjacent to the negative electrode and decreases towards the grounding electrode. Charge decay is observed including two processes, in which a fast decay initially occurs followed by a slow process. Furthermore, it is suggested that the presence of localized surface states should be account for the surface charging, the charge decay is ascribed to the recombination between de-trapped charges and positive ions which are in the air.
杜伯学, 高宇, 刘彦君. 聚萘二甲酸丁二醇酯试样表面电荷迁移与消散机理[J]. 电工技术学报, 2009, 24(3): 36-40.
Du Boxue, Gao Yu, Liu Yanjun. Charge Migration and Decay on Polybutylene Naphthalate Surface. Transactions of China Electrotechnical Society, 2009, 24(3): 36-40.
[1] Nakanishi K, Yoshioka A, Shibuya Y, et al. Charge accumulation on spacer surface at dc stress in compressed SF6 gas[C]. Gaseous Dielectrics Ⅲ, Pergamon Press: New York, 1982: 365-373. [2] Farish O, Al Bawy I. Effect of surface charge on impulse flashover of insulator in SF6 [J]. IEEE Trans. EI, 1991, 1(2): 443-452. [3] Al Bawy I, Farish O. Insulator flashover in SF6 under impulse voltage conditions[J]. IEE Proceeding-A, 1991, 138(1): 89-97. [4] Knecht A. Development of surface charges on epoxy resin spacers stressed with direct applied voltages[C]. Gaseous Dielectrics Ⅲ, Pergamon Press: New York, 1982: 356-364. [5] 汪沨. 绝缘子表面电荷积聚及其对沿面闪络影响的研究[D]. 西安: 西安交通大学, 2003. [6] 汪沨, 方志, 邱毓昌. 高压直流GIS中绝缘子的表面电荷积聚的研究[J]. 中国电机工程学报, 2005, 25(3): 105-109. [7] Wang F, Qiu Y C, Pfeiffer F, et al. Insulator surface charge accumulation under impulse voltage[J]. IEEE Trans. DEI, 2004, 11(5): 847-854. [8] Elkhodary S M, Hackam R. Surface charge decay under the influence of prior applied voltage in freon[C]. IEEE Annual Report of Conference on Electrical Insulation and Dielectric Phenomena, 1994: 749-754. [9] Fang Z, Fouracre R A, Farish O. Investigations of surface charging of DC insulator spacers[C]. IEEE Annual Report of Conference on Electrical Insulation and Dielectric Phenomena, 1996, (1): 20-23. [10] Das Gupta D K. Electrical properties of surfaces of polymeric insulators[J]. IEEE Trans. EI, 1992, 27(5): 909-923. [11] Du B X, Liu H J, Liu Y. Effects of gamma-ray irradiation on dielectric surface breakdown of polybu- tylene polymers[J]. IEEE Trans. DEI, 2007, 14(3): 696-701. [12] Pederson A. On the electrostatics of probe measu- rements of surface charge densities[C]. Gaseous Dielectrics Ⅴ, Pergamon Press: New York, 1987: 235-241. [13] Faircloth D C, Allen N L. High resolution measure- ments of surface charge densities on insulator surfa- ces[J]. IEEE Trans. DEI, 2003, 10(2): 285-290. [14] Jaitly N C, Sudarshan T S. In-situ insulator surface charge measurements in dielectric bridged vacuum gaps using an electrostatic probe[J]. IEEE Trans. EI, 1988, 23(2): 261-273. [15] 丁立健. 真空中绝缘子沿面预闪络和闪络现象的研究[D]. 北京：华北电力大学, 2001. [16] 刘志民, 邱毓昌, 冯允平. 对绝缘子表面电荷积聚机理的讨论[J]. 电工技术学报, 1999, 14(2): 65-68. [17] 张冠军. 真空中固体绝缘材料沿面闪络的起始机理和发展过程[D]. 西安: 西安交通大学, 2000. [18] Chalmers I D, Wang C X, Farish O. Dielectric surface charge phenomena in a space environment [C]. Pulsed Power Conference, 1989: 804-807. [19] Hama H, Hikosaka T, Okabe S, et al. Cross-equip- ment study on charging phenomena of solid insulators in high voltage equipment [J]. IEEE Trans. DEI, 2007, 14(2): 508-519. [20] Chen G, Xu Z, Zhang L X. Measurement of surface potential decay of corona charged polymer films using the pulsed electroacoustic method[J]. Measure- ment Science and Technology, 2007, 18: 1453-1458.
2009, Vol. 24 
