Investigation on Regularities of Self‐Healing Breakdown in Metallized Film Capacitors for AC Application

Metallized film capacitors (MFCs) exhibit a distinctive self‐healing capability, making them particularly suitable for reactive compensation in high‐voltage power systems. However, frequent self‐healing breakdowns or failures can significantly compromise capacitor lifespan and system stability. The underlying mechanisms governing self‐healing behavior in AC applications remain insufficiently understood. This study establishes an experimental platform to systematically examine the influence of various factors on AC capacitor self‐healing performance, while proposing design recommendations to minimize self‐healing energy without compromising success rates. Key findings demonstrate that increased voltage leads to a dramatic expansion of self‐healing area; elevated temperatures facilitate reduced self‐healing energy but degrade insulation properties when excessive; thicker metallized films decrease power loss at the expense of substantially higher self‐healing energy; and greater inter‐layer pressure effectively diminishes self‐healing energy. For optimal capacitor design, excessive field strength should be avoided; moderately increased operating temperatures enhance self‐healing performance but must be balanced against thermal degradation risks; and film thickness selection requires careful consideration of both self‐healing characteristics and thermal management. These findings offer valuable insights for the design optimization of AC capacitors in power system applications.