Surface charge inversion algorithm based on bilateral surface potential measurements of cone-type spacer

To study the surface charge distribution of high-voltage direct-current (HVDC) spacers for gas insulated lines (GIL), a surface charge inversion algorithm based on surface potential measurements is necessary. However, previous studies on inversion calculation of surface charge density only considered the surface potential of one side, neglecting the effect of residual surface charge on the other side of the spacer; this leads to an inaccurate inverted surface charge distribution. In this paper, the inversion algorithm methods used to determine surface charges over the past few decades were summarized, and their advantages and disadvantages were discussed. Based on the previous charge inversion algorithms, an improved surface charge inversion algorithm considering the surface potential of both sides of a cone-type model spacer was developed. The improved method was verified experimentally using a cone-type model spacer. Compared with that obtained by previous charge inversion algorithms, the charge distribution derived from the improved algorithm was closer to the situation determined from theoretical analysis. This work has practical relevance for the surface charge measurement of cone-type spacers and offers a new orientation in the surface charge analytical algorithm.