SMA SB 4200TL Multi-String - Manual (Page 57)

SMA Technologie AG Glossary
Operating Instructions SB4200-12:FE4804 Page 57
7 Glossary
AC
Abbreviation for „Alternating Current“
Central inverter
Inverter concept where all PV modules are wired among each other (switching in se-
ries and / or in parallel). One single inverter feeds into the external grid. Costs for a
central inverter concept are lower, but installation might be much more complicated
and yield losses may occur due to shadowing of individual solar modules.
DC
Abbreviation for „Direct Current“
Derating
Controlled reduction of power, mostly depending on temperatures of certain modu-
les. Compared to a complete shutdown of a device, which is a usual procedure as
well, the negative impact on the external grid is lower with derating.
Grid-tied plant
PV plant connected to a public electricity grid run by an external supplier company.
Inverter
Device to convert the direct current (DC) supplied by the PV generator into alterna-
ting current (AC) which is required for the supply of most consumers and especially
for feeding into the public grid. Inverters for PV plants usually include one or more
MPP trackers.
Maximum Power Point „MPP“
The operating point (current / voltage) of the PV generator where this generates ma-
ximum power under the current conditions. The position of the MPP changes conti-
nuously, e. g. depending on irradiation and temperature.
MPP tracker
Unit that adjusts current and voltage of the PV generator in a way so as to make the
generator operate in its maximum power point.
MSD
The „Mains monitoring with allocated Switching Devices“ is an obligatory safety de-
vice which interrupts the inverter’s feeding of PV power to the grid if the external po-
wer generators have shut down.