CHARACTERISTICS AND RISKS OF BROKEN BYPASS DIODE WITH INDUCED LIGHTNING

抄録

Surge voltage or current induced by lightning strike around a PV system often causes short circuit failure of a Bypass diode (BPD) on the PV module. We investigated the characteristics of PV modules and BPDs broken by the induced lightning and evaluated risk of the short circuit failure of the BPD. The BPDs on the broken PV modules with slight damage were often shorted. The BPDs on the broken PV modules with serious damage had previous phase that was a short circuit failure. The shorted BPD was heated with current from a cell string of the shorted BPD in case the broken PV module did not operate. If a PV module had a partial shade in a cell string with the shorted BPD, the shorted BPD was heated by the current from other cell strings without the shade. These results show that if the shorted BPD is left unattended, it can cause serious accidents of PV system such as an overheating or a fire.