Temperature effect on space charge dynamics in multi-layer insulation Fluorinated Ethylene Propylene (FEP) Low Density Polyethylene (LDPE)

Space charge behavior at dielectric interfaces in multi-layer Fluorinated Ethylene Propylene (FEP) and Low Density Polyethylene (LDPE) subjected to a dc field has been investigated as a function of the temperature using the pulsed electro acoustic (PEA) technique. A sandwich structure constituted by two dielectric films not identical FEP/LDPE was used to study the charging propensity of electrode/dielectric and dielectric/ dielectric interface. The time dependence of the space charge distribution was subsequently recorded at different temperature under field (polarization) and short circuit condition (depolarization). Experimental results demonstrated that charge injected process take place in all cases. However it is shown that the amount of interfacial charge depends drastically on the temperature. It has greater influence on the distribution, injection and mobility of space charge in the bulk and at dielectric/ dielectric interfaces.