Abstract
The quality of cable insulation is an important factor in the reliability of electrical power transmission. Space charge accumulation in dielectrics during operation could be responsible of dielectric breakdown. The development of non-destructive space charge measurement methods make it possible to assess the quality of dielectrics by monitoring the evolution of space charges.This manuscript details the procedure applied to develop a non-intrusive space charge measurement bench for model cables (scale model of full-size cables). The technique used is the thermal step method. This technique is based on the measurement of a displacement current between the conductive core and the external screen of the cable after the application of the thermal stimulus generated by Joule effect. From this current we can calculate the space charges and the electric field distribution in the entire length of cable tested.The aim of this thesis is development of electric converter to apply a thermal stimulus by Joule effect in model cables. The multicellular parallel converter structure with magnetic coupler is used. The experiments carried out with a prototype of a multicellular converter with 8 coupled phases are in accordance with the simulations results and confirm the principle of space charge measurement.