Self-healing shunt capacitor detection

Are metallized film capacitors self-healing?

Abstract: Metallized film capacitors (MFCs) are known for their self-healing (SH) properties, enabling efficient and reliable operation, even under challenging conditions. These SH events have the potential to inflict damage on both the polypropylene (PP) film and the electrode layer.

How reliable are metallized film capacitors?

RP serves as a valuable tool for evaluating the safety of MFCs with an unknown SH history, contributing to the assessment of their reliability. Metallized film capacitors (MFCs) are known for their self-healing (SH) properties, enabling efficient and reliable operation, even under challenging conditions.

How does SH affect capacitance loss?

As the SH number increases, the probability of SH breaking only one layer of film in each event rises; Capacitance loss calculations need to account for the winding structure of the capacitor. It was observed that capacitance loss is nonlinearly related to the total electrode evaporation area.

What happens if a capacitor has a SH voltage?

It mainly results in capacitance loss of the capacitor component. Additionally, SH in capacitors is typically random. Even at the same SH voltage Ush, the SH energy Wsh can vary.

Does SH damage affect the reliability of a capacitor?

However, not all types of SH damage lead to catastrophic failure of the capacitor. Thus, finding the threshold of SH that has little impact on the reliability of the capacitor is important. This article classifies SH events based on their SH energy, ranging from safe to risky, and establishes thresholds for safe SH.

Are metalized film capacitors a good choice for liquid impregnant capacitors?

To achieve such performances, metalized film capacitors (MFC) are adopted. Comparing with conventional liquid impregnant capacitors, the high energy density of MFCs is derived from the self-healing properties of metalized film.