圆台形绝缘子的表面电荷密度反演算法

The surface charge on spacer in DC gas insulated lines(GIL) is an important factor to trigger surface flashover. It is still an important subject to precisely measure and compute surface charge distribution. Consequently, the surface charge density and surface electrical field calibration methods were researched based on the multipoint measurement technique in which the influence of probe was taken into account. The spatial resolution of the measurement system was evaluated. The signal-to-noise ratio (SNR) and square root of peak-mean square error (PMSE) were employed to estimate the error of this computation method. The surface potential of a downsized cone-type spacer, which is adhered with metallic particles under DC voltage charging in atmospheric SF₆ gas, was measured by a Kelvin vibrating electrostatic probe. The surface charge distribution was computed by this calibration method. The results reveal that the location of metal particles can be clearly found in the charge density distribution map. The spatial resolution and charge resolution of the algorithm are 2.0 mm and 0.95 pC/(mm²•mV), respectively. The charge density distribution and potential distribution are quite different. The potential distribution can not be used to replace the actual charge density distribution. The algorithm can be applied to the calculation of surface charge density of rotationally symmetric insulation materials, which can provide theoretical guidance for the research of DC GIL insulator surface charge distribution characteristics.