The functional relation between partial discharges and induced charge

Analytical expressions are deduced for the quantitative evaluation of the charge induced on an electrode by a partial discharge (PD) within a dielectric body. Two approaches have been employed to effect this evaluation. These are characterized by the λ function and the φ function, and the essential relationships to be fulfilled by λ and φ are derived. The principal difference between these functions is how the dielectric polarization is accounted for, either implicitly (λ) or explicitly (φ). This difference is brought clearly into focus. Thereafter the application of these functions to PD studies is considered. It is demonstrated quantitatively, that perturbations in the dielectric polarization, brought about by the PD, can contribute significantly to the magnitude of the induced charge. As a consequence, the currently accepted approach to PD energy considerations should be re-examined