Calculation of electrical field of spherical and cylindrical gas voids in dielectrics by taking surface conductivity into consideration
Küçük Resim Yok
Tarih
2005
Yazarlar
Dergi Başlığı
Dergi ISSN
Cilt Başlığı
Yayıncı
Emerald Group Publishing Ltd
Erişim Hakkı
info:eu-repo/semantics/closedAccess
Özet
Purpose - To determine the electrical field E-1(t) in spherical and cylindrical gas voids existing in an insulator by considering surface conductivity of gas voids having an electrical permittivity of epsilon(1) and conductivity of gamma(1) for DC and AC situations. Design/methodology/approach - Analytical expressions satisfying Laplace equation for inside and outside of the cylindrical and spherical gas voids in an insulator located in an external electrical field having a definite time dependent character, have been derived by considering the surface conductivity of the gas void. The coefficients included by these analytical expressions have been determined by utilizing the continuity equation of the current on the surface of the voids. Findings - It has been demonstrated that the electrical field remains uniform in spherical and cylindrical gas voids when the surface conductivity of gas void has been considered. It has been determined that the contact charging process of different shaped particles has an exponential characteristic, and some expressions have been derived to determine the time constants of this process for practical purposes. Practical implications - The results have been applied to the problems about contact charging of semi-spherical and semi-cylindrical insulated particles located at a charged surface and problems about the calculation of onset discharging voltage of ionization process in dielectric including gas voids. Originality/value - For spherical and cylindrical gas voids, the onset discharging voltage corresponding to the ionization process occurring in gas voids has increased by increasing the surface conductivity of the void. For the limit value of the surface conductivity, the voids in the insulator behaves like metal particles distributed into the insulator, for this reason, at the outside of the void, especially in the regions where the voids are close to the electrodes and each other, the electrical field will be non-uniform and will increase. This situation will cause the ignition of the partial discharge and destroy to the insulator.
Açıklama
Anahtar Kelimeler
electric fields, electrical conductivity, electrical properties, gases, geometric planes and solids
Kaynak
Compel-The International Journal For Computation and Mathematics in Electrical and Electronic Engineering
WoS Q Değeri
Q4
Scopus Q Değeri
Q3
Cilt
24
Sayı
4
