PULSED ELECTROACOUSTIC METHOD FOR MEASUREMENT OF CHARGE ACCUMULATION IN SOLID DIELECTRICS

This paper describes the principle of the pulsed electroacoustic (PEA) method, which was developed a few years ago for profiling the space charge distribution in an acoustically homogeneous solid material. Initially the PEA method could indicate the space charge distribution in the materials only indirectly. Some data processing, for example deconvolution, was necessary to obtain the charge profile. Some very important improvements were made recently to the PEA method which eliminated the need for deconvolution. This paper describes the latest improvements and the practical construction of the detecting electrode system under which the output signal is linearly proportional to the space charge distribution. Nowadays the PEA method can be used to measure the space charge distribution with or without dc electrical stress, not only in free-standing dielectric plates but also directly in coaxial cables.