IEC TR 62380 or MIl_HDBK-217f give equations for reliability prediction of components depending on temperature, quality, environment etc. Sometimes application notes can be useful as well, for instance page 16 of

http://www.electronicon.com/fileadmin/inhalte/pdfs/downloadbereich/Katalog/neue_Kataloge_2011/200.003-020021_App-notes.pdf

Regards,

Arnold

We also recognised that also film capacitors were one of the tools to ,extend the life of PV converters. The main failure rate with electrolytic capacitors was not the failure rate at mid life, but the end of the bath curve at some 50 000 hours of operation. Internal corrosion makes some part inactive and the electrolyte dries out causing more losses until is shortens it life by overheating.

Film capacitors loose capacitance by self healing, but have a more gradual degradation. Also thermal stresses reduce the lifetime. So, several smeller capacitors will heat less and will have less internal stresses than one large one.  I'm  not sure models reflect all these aspects.

I teach reliability engineering course at Yale University and some of my quantitative examples applies to estimating/ predicting the service life of power electronics including film capacitors. Here is how to calculate the service life of film capacitors:

If you know the failure times of film capacitor from experiments, then you apply a two-parameter Weibull model to this data and calculate the mean time to failure (MTTF) to get the serive life. Another simpler method is to find out the failure rate (lambda) of film capacitor (you can get it from a literature search). The service life is then the reciprocal of the failure rate of this component.

Hope this helps answer your question.

Thank you experts for your answers.. They are indeed helpful.

I also found one good link for service life.

http://www.illinoiscapacitor.com/tech-center/life-calculators.aspx

Regards

Aalok

Well, I think capacitor aging process is good enough to calculate the service life of film capacitor. Capacitor industry guidelines exist which define end of capacitor service life. These are based on a decrease in the capacitance and/or an increase in the series resistance. Typical values are shown in Table. The capacitor still operates at end of life, just as the dam still holds water, but the capacitor has a high probability for a short circuit failure and the capacitor should be taken out of service. Note that after years of capacitor industry experience, the end of life numbers still cover a range and are only guidelines.

                         Elements                                                    Film Capacitor

                 Max loss of capacitance                                  -5% to -10%

                 Max increase in series resistance             +100% to +150%

 http://www.emersonnetworkpower.com/documentation/en-US/Services/Market/Data-Center/Documents/LS%20Literature/White%20Paper/Capacitors-Age-and-Capacitors-Have-an-End-of-Life-WP-SL-24630.pdf

Check out this link might be helpful to u.

this is an interesting related article

https://cds.cern.ch/record/2038610/files/45-56-Gallay.pdf

The other way of looking is just checking the polymer type and its expected life based on UL746.

keep in mind temperature is a major factor in any organic material aging