Solar inverter destruction and module degradation - reasons, effects and solutions!
Background:
Since the last three years the internet is full of reports of solar inverter disturbances, fails, destruction, replacement activities, as well as of callback activities of different well-known manufacturers. In Spring 2013, like in the years before, new SWR explosions with fire occurred and they had their cause in capacitor problems.
German example of one numerous internet reports on that problem:
http://www.photovoltaikforum.com/wechselrichter-f3/sma-5000-tl-abgebrannt--t7159.html
Extincting those fires is a very dangerous work for the fire workers.
http://www.feuerwehrverband.de/fileadmin/dfv/Dateien/Fachwissen/DFV-Positionspapier%20PV-Anlagen.pdf.
For the owner of the device a failure always means loss of money and much effort to correct it. Often the PV / solar inverter devices have been financed via loan of money, which have been adapted to the potential SWR value. Additional, costs for device failure are not included and insurances often do not pay them either.
Reasons of SWR failure and destruction.
Solar inverters are affected by high temperature and wetness differences. It is no surprise that mainly the used capacitors are destroyed. The test norms for X2 and Y2 capacitors go back to the 1970s and 1980s.At this time mostly linear consumers (trafos) are used. The different norms had been based on those disturbance values.
By introduction and usage of performance transistors, GBT´s, thyristor controls, etc. also the disturbance values in the supply grid have changed. The norms for components (mainly for capacitors) have not been adjusted. Please read this report:
http://www.bajog.de/en/technical-report/reason-for-x2-and-y2-demolition.html
and:
http://www.bajog.de/en/technical-report/required-adjustment-to-the-standard.html
These both reports explain the reasons of capacitor failure.
Reasons and results of PV modular fails.