The Effect of an Electrostatic Probe on Measurement of the Surface Charge

The problem of charge accumulation is very serious in the case of high voltage director current (HVDC) transmission when the corona discharge is generated along the conductor. In order to measure the surface charge on the insulating parts, the most popular method is based on the electrostatic meter. But the probe of the electrostatic meter will influence the distribution of the surface charge which makes the measurement inaccurate. In this paper, the influence of the electrostatic probe using the direct method on the measurement of the surface charge on a metal plate sample is discussed. The surface charge with an electrostatic probe near the metal plate sample is simulated. The electrostatic probe will distort the spatial potential and it will influence the distribution of surface charge of the test sample. The measuring distance has to be taken into account in the surface charge inversion calculation. However, the ill-conditioned equations may be occurred and the error of calculation will increase.