Open AccessSome Observations on the Dielectric Breakdown and the Importance of Cavities in Insulating Materials used for Cables and Electrical Machines
Author(s) -
M. G. Danikas,
Athanasios Karlis
Publication year - 2011
Publication title -
advances in electrical and computer engineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.254
H-Index - 23
eISSN - 1844-7600
pISSN - 1582-7445
DOI - 10.4316/aece.2011.02020
Subject(s) - dielectric , materials science , engineering physics , electric breakdown , electrical engineering , composite material , electrical breakdown , dielectric strength , optoelectronics , computer science , engineering
Partial discharges (PD) contribute greatly to the ageing and the breakdown of solid insulating materials. In the present paper, some conductivity measurements are performed relating the conductivity of inner walls of an enclosed cavity to the behaviour of PD in the case of polyethylene and of epoxy resin. The temporary decrease of the PD magnitude is explained in terms of the increase of the cavity inner wall conductivity. The PD behaviour is studied in epoxy resin samples and is explained with the aid of Pedersen's model. Scanning Electron Microscope (SEM) photographs indicate the sort of damage suffered by the cavity walls under electrical stress