Location of partial discharges in high voltage equipment using ionizing rays

A theoretical analysis of the influence of ionizing radiation on the development of free charge carriers in the cavity of the epoxy insulation is outlined. From the analysis it follows that number of free charge carriers is increasing with increasing energy of photons and that the dominant effect is the emission of electrons from the surrounding material into the cavity. The influence of ionizing rays on the inception voltage of partial discharges is experimentally investigated on the epoxy samples with spherical cavities of various diameters and on inception voltage of corona in the configuration circular conductor-plane electrode. It is found that irradiation stimulates partial discharges and changes mainly the inception voltage of discharges. The method of location is based on change of conditions for discharge inception in individual parts of equipment due to local irradiation