A Study of the Behavior of a Uniaxially Oriented Polyethymene Tape/Oil Insulating System Subjected to Electrical and Thermal Stresses

Some Factors Affecting the Breakdown Strength of Solid Dielectrics: A Short Review

“…Previous work on this has shown that the AC breakdown strength of a polypropylene laminated paper/oil combination decreases as swelling worsens [37]. Similar conclusions were reached with another composite insulating system consisting of UOPE/DDB oil [33][34][35]. In [38], the problem of solid/liquid combination was attacked from another angle, namely that of the interface and also in terms of the water content.…”

“…A combination of polymer and of a low viscosity absorbing liquid was proposed several years ago. That was a combination of uniaxially orientated polyethylene (UOPE) and dodecylbenzene (DDB) oil [33][34][35]. Experimental results indicated that since collision impact of electrons accelerated in the free volume is the dominant cause for electrical tree initiation, liquid impregnation is a promising way to improve the performance of polymeric materials and to rise the breakdown strength [36].…”

“…However, as mentioned in [29], orientated polymers may be subjected to a rapid shrinkage above a critical temperature. Degradation of UOPE films has been observed several years ago, especially when these are combined with DDB oil [33][34][35]. Besides the fact that such a composite system (UOPE/DDB oil) starts having problems at about 110 o C, oils with aromatic constituents can cause crazing to polymers much more easily than polybutene oil [46,47].…”

Insulating Materials at Very Low Temperatures: A Short Review

“…This is probably due to the existing probability of weak points of the electrical insulation at butt gaps [49]. Regarding the role of butt gaps and their related parameters, there is a striking similarity between the observations of the above publication and those reported using conventional insulating systems [50,51], i.e. that the butt gaps -if not well impregnated -may be the weak point of a composite insulation.…”

Partial discharges in epoxy resin voids and the interpretational possibilities and limitations of Pedersen's model

“…Partial discharges (PD) in voids enclosed in solid insulation, on the other hand, constitute a danger, since their action may cause deterioration, eventual insulation degradation and finally breakdown. Efforts have been made in the course of years to relate PD magnitude, energy and other parameters to insulation damage [14,15]. Various models were proposed in order to explain the behaviour of PDs in voids and to estimate their magnitudes [10][11][12][13].…”