Glossary
SMA Solar Technology AG
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SB_SMC_Schueco-BEN093730
User Manual
7 Glossary
AC
Abbreviation for "Alternating Current"
DC
Abbreviation for "Direct Current"
Derating
A controlled reduction in performance, usually dependent on component temperatures. Compared
with the (also common) practice of completely shutting down the device, derating has a less drastic
effect on the external grid.
Grid-connected system
PV system which is connected to the power supply grid of an external energy supplier.
Grid impedance
The grid impedance is a characteristic grid specification, which is determined both by the grid
infrastructure, and by the number of power suppliers and power consumers. If supply to the grid
section drops due to a grid shutdown on the part of the adjacent energy suppliers (medium-voltage
transformers), the grid impedance changes abruptly. In order to detect this occurrence, and to prevent
the formation of an unwanted stand-alone grid, SMA Grid Guard monitors the grid impedance and
disconnects the inverter from the grid in the event of a sudden impedance variation.
Inverter
A device for converting the direct current (DC) from the PV generator into alternating current (AC),
which is used by most normal household devices, and especially for feeding energy into an existing
supply grid.
Maximum Power Point "MPP"
The operating point (current / voltage) of the PV generator at which the highest possible performance
under the prevailing conditions is achieved. The actual MPP changes constantly, depending on the
level of solar irradiation, cell temperature, etc.
MPP tracker
A device that adjusts the voltage and current of a PV generator so that it operates at its
"Maximum Power Point".
PV
Abbreviation for "photovoltaic" describing the conversion of solar energy into electrical energy.
PV generator
Technical device for the conversion of solar energy into electrical energy. This normally refers to all
installed and electrically connected solar modules in a PV system.
