Influence of residual charges on the vibration of filter capacitor components

Abstract

The noise of filter capacitors in high voltage direct current (HVDC) transmission converter stations has raised wide concern. In this paper the influence of residual charges on the surface of dielectric film on the vibration of capacitors is studied by experiments and simulation. A component of filter capacitor is made by enwinding two aluminum foils between them with three layers polypropylene films, and pressed into a rectangular plate form, then packed by insulation paper. A stack of filter capacitor consisted of some components in series or parallel connection. An electrometer is used to test the electric potentials under the unfolded one layer of dielectric film of a component of capacitor, and the residual charge densities of the dielectric film are calculated by means of the measured electric potentials. The results show that the residual charge density distribution on dielectric film is uneven and irregular. The electric field force of the dielectric film with residual charges of different orders of magnitude is simulated by using finite element software. Finally, a programmable power supply is used to apply sinusoidal voltage with different amplitude to a capacitor component, and the vibration of the component surface is tested by a laser vibration meter. The test results show that the residual charges on the dielectric film have significant impact on the vibration of capacitor component.