Self-healing is a process by which the capacitor restores itself in the event of a fault in the dielectric which can happen during high overloads, voltage transients, etc.
When insulation breaks down, a short duration arc is formed (figure 1)

 
The intense heat generated by this arc causes the metallization in the vicinity of the arc to vaporise (figure 2).
 

Simultaneously it re-insulates the electrodes and maintains the operation and  integrity of the capacitor (figure 3).
 



 

Released for: Schneider Electric Egypt and North East Africa