SMA America, LLC
4 Product Description
Installation Manual
SB3-5TLUS22-IA-en-10
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4.9 SD Card Slot
The inverter is equipped with an SD card slot. You can use the SD card when required to update the
inverter firmware.
4.10 Anti-Islanding Protection
The inverter has an active safety algorithm to protect against islanding. A stand-alone grid occurs
when the power distribution grid is switched off and the inverter attempts to continue to feed in to the
power distribution grid. For this to happen, the remaining load must be resonant at 60 Hz and exactly
match the power of the inverter. The effect of the safety algorithm is that, in the event of the power
distribution grid being switched off, the PV plant does not supply any current to a symmetrical load
that is resonant at 60 Hz.
4.11 Varistors
Varistors are voltage-dependent resistors that protect the inverter against overvoltage. The inverter is
equipped with four thermally monitored varistors on the DC side. It may be necessary under certain
circumstances to replace the varistors (see Section 9.6 "Replacing DC Varistors", page 78).
