SMA STP 50-40 Operating Manual page 24

4 Product Overview
Multifunction Relay
The inverter is equipped with a multifunction relay as standard. The multifunction relay is an
interface that can be configured for the operating mode used by a particular system.
SMA ShadeFix
The inverter is equipped with the shade management system SMA ShadeFix. SMA ShadeFix uses
an intelligent MPP tracking system to determine the operating point with the highest output during
shading conditions. With SMA ShadeFix, inverters use the best possible energy supply from the PV
modules at all times to increase yields in shaded systems. SMA ShadeFix is enabled by default. The
time interval of SMA ShadeFix is usually 6 minutes. This means that the inverter determines the
optimum operating point every 6 minutes. Depending on the PV system or shading situation, it may
be useful to adjust the time interval.
String-failure detection
The string-failure detection measures the total current of every input and continuously calculates the
mean values for the inputs in question. The total currents are compared with the mean values. If a
total current exceeds or falls short of the mean value by the set tolerance value, an event is
reported. Marginally increased total currents are reliably detected over several query intervals and
distinguished from typical current fluctuations of the PV array. String-failure detection is deactivated
by default and must be activated. In addition, the tolerance value can be set via the user interface
and the mean values read off.
Surge arrester type 1 and 2
On the AC and DC side, the inverter is equipped with slots for type 1 and 2 surge protection
devices. The surge protection devices limit dangerous overvoltages. The surge protection devices
can be retrofitted.
SMA ArcFix
Only the STP 50-41 is equipped with this function.
SMA ArcFix is an Arc Fault Circuit Interrupter (AFCI). With this function, the inverter effectively
detects arcs on the DC side and interrupts them.
A detected electric arc causes the inverter to interrupt feed-in operation. To restart feed-in operation,
the operational disruption which has occurred must be reset. Alternatively, the arc-fault circuit
interrupter can be activated without inhibiting operation. Depending on the country data set, arc
fault detection is activated or deactivated by default. If the installation conditions permit this, you
can change the default setting.
SMA ArcFix complies with the requirements of the draft standard IEC 63027 ED1 (82/1636/
CDV) and in the scope of IEC 63027 corresponds to the following installation classes:
• F-I-AFPE-1-6-2
• F-I-AFPE-2-3-2
SMA Smart Connected
SMA Smart Connected is the free monitoring of the product via the SMA Sunny Portal. Thanks to
SMA Smart Connected, the operator and qualified person will be informed automatically and
proactively about product events that occur.
24 STP50-4x-BE-en-23
SMA Solar Technology AG
Operating manual