Metallized film capacitor is widely used in such electrical equipment as converter valves and

under the influence of rapid operation of power electronic switches

will be subjected to high-frequency shocks

it is therefore necessary to study the characteristics of the capacitor in a wide frequency range. In this paper

the single capacitor elements is taken as the study object. The impedance characteristics of capacitor elements in the range of 20 Hz~2 MHz are measured by using a digital bridge. An equivalent circuit model is set up by a combination of data fitting and experimental measurements and the impedance characteristics and equivalent circuit parameters at different frequencies are analyzed. The study results show that at low frequencies (<150 kHz)

the equivalent circuit model with constant parameters can accurately describe the impedance characteristics and internal physical processes of the capacitor element

while at high frequencies (>150 kHz)

the current distribution in different areas inside the capacitor element will change

resulting in a frequency change of such parameters as equivalent inductance and equivalent resistance of the element

which causes a change in the impedance characteristics. The results of this paper can provide guidance for analyzing the degradation mechanism of capacitor under high-frequency shocks.