Evolution of space charge measurements: new approaches to physical problems

The author has shown that although space charge determination techniques are now well established, many new directions of research should bring information on the behaviour, the ageing and the electrical evolution of insulators. Real time measurements of space charge distributions at high repetition rate will permit study of the dynamics of charges under AC or rapidly varying electric stress. Three dimensional mapping of the charge or dipole distributions will help understanding the role of space charge in electrical ageing and breakdown, or the nonhomogeneous polarisation of dielectrics. Finally, by combining space charge measurement with complementary techniques, it will be possible to reach new types of information. The pressure wave propagation method, pulsed electro-acoustic method and thermal step method are discussed