Self-healing capacitor capacity test

What is self healing metallized capacitor?

Self- healing is the ability of a metallized capacitor to clear a fault area where a momentary short occurs due to dielectric breakdown under voltage. The conditions that lead to a fault vary. In the production of the dielectric film, contamination can occur or a process control problem can result in compromised dielectric strength.

Are metallized film capacitors self-healing?

In order to study the self-healing characteristics of metallized film capacitors, an experimental platform was established to study the effects of voltage, temperature, shunt capacitance, film thickness, and interlayer pressure on the self-healing energy of metallized film capacitors.

Does film thickness affect the self-healing energy of a capacitor?

The self-healing energy of a 10 μm thick film is 3.46 times higher than that of a 6 μm thick film, and the film thickness has a significant effect on the self-healing energy of the capacitor.

Are capacitors self-healed?

After such a breakdown, capacitors have normal characteristics and can be considered self-healed. However, the remnants of filaments increase local electric fields in the dielectric, injection of electrons, and post-CCS leakage currents in the parts.

How long does a self-healing shunt capacitor last?

From the typical waveform, it can be seen that during the self-healing process, the voltage across the specimen remains basically constant due to the presence of the shunt capacitor, and the duration of the self-healing current is about 1–2 μs. Based on the experimental waveform and Eq. (1), the self-healing energy E sh can be calculated.

Do self-healed capacitors grow at rated voltages?

The filaments in self-healed capacitors continue growing at rated voltages, although at a much lower rate than at pre-breakdown voltages. This growth increases electric fields and leakage currents with time under bias for MnO2 capacitors.