Study on Influence of Internal Electrode Deformation Difference on Capacitance of Standard Capacitor
Electrode displacement method is a voltage coefficient measurement method of high voltage standard capacitor concerning internal electrode displacement.This methods assumes that the displacement and capacitance on top of electrode along the horizontal direction exist function relation,but the type of action force causing the deformation of the internal electrode is not considered.Since the deflection distri-bution of internal electrode is different under different action forces,the actual capacitance is different when the same internal electrode top surface displacement is generated by different forces,which may affect the accuracy of voltage coefficient measurement.For studying this difference,a set of cantilever beam type 400 kV high voltage standard capacitor is simulated and tested.The results show that the maximum displacement on top surface of the capacitor is 52 μm and the maximum voltage coefficient is 13.8×10-6 when the voltage varies from 20 kV to 350 kV.Under the action of different forces,the deflection distribution of the internal electrode is different,but the resulting voltage coefficient uncertainty is only 0.098×10-6.Therefore,in case of considering the maximum allowable error of voltage coefficient of high voltage standard capacitor at 10-6 magnitude,the influence of internal electrode deformation difference on voltage coeffi-cient measurement experiment can be ignored,thus verifying reliability of electrode displacement method.
high voltage measurementhigh voltage standard capacitorvoltage coefficientelectrode displacement methoduncertainty