Mobility evaluation from space charge measurements performed by the pulsed electroacoustic technique

This paper presents an approach having the purpose to obtain charge mobility estimation from space charge measurement data, precisely from the depolarization (volt-off) characteristic provided by the pulsed electro-acoustic technique (PEA). General and approximate expressions are given for mobility calculation. These expressions are applied to experimental results coming from tests made on cross-linked (XLPE) specimens cut from high-voltage cables. Reasonable mobility estimates as function of volt-off time are obtained for the total charge accumulated in the specimens during poling, thus validating the proposed approximate expression. These expressions can be applied even in the absence of clear charge dynamic, such as packet charges, and on the basis of any technique for space-charge measurement able to provide depolarization characteristics.