Assessment of space charge based on PEA measurement

Abstract

Accumulation of charge within a polymericinsulating material under DC field stresses is a matter of concern. Charge accumulated within the polymeric insulating material depends on the composition and structural properties of the material. In this work, spatial distribution of charge trapped within the volume of the dielectric material is measured using the Pulsed Electroacoustic technique (PEA). Space charge in unaged and thermally aged polyethylene is studied. Thermal ageing is carried out for different conditions and different periods. Space charge distribution for these variously aged samples is studied. Trap depth and trap controlled mobility is estimated from space charge measurement. Trap depth and mobility is seen to vary in unaged and aged materials and therefore can be used as ageing markers. Also the difference in polyethylene and epoxy is studied.