Safety; Intended Use - SMA SUNNY BOY 5000-US Installation Manual

Safety

2 Safety

2.1 Intended Use

The Sunny Boy is a PV inverter which converts the DC current of the PV array to AC current and feeds
it into the power distribution grid. The Sunny Boy is suitable for use with fuel cells, small wind turbine
systems, and other DC current sources. The Sunny Boy takes the current from a DC source and
converts it into AC power for the power distribution grid. This power is then supplied to the local
consumers (C). Surplus energy is fed into the power distribution grid (E). Due to the power that is
consumed by the local devices, the amount of power required from the power distribution grid is
reduced. An energy surplus may even result in the energy meter (D) of your plant running backward.
This power may also be recorded as power credits by the electric utility company depending on the
interconnection agreement.
Principle of a PV Plant with a Sunny Boy
Position Description
A PV array
B Sunny Boy with DC disconnect
C Local consumers
D Energy meter
E Power distribution grid
Ground Fault Detection and Interruption in the PV Array
All Sunny Boy inverters have a system for detecting ground fault errors in the PV array (GFDI)
according to the National Electrical Code
The PV array is operated in a grounded configuration. Depending on the plant type, the negative or
positive conductor of the PV array is connected to the grounding system in the Sunny Boy. According
to UL 1741, the GFDI protection is always active when sufficient DC voltage is present to switch on
the LC display in the Sunny Boy.
If a ground fault current larger than 1 A is flowing, the Sunny Boy switches off and displays the
interference. After the ground fault has been located and eliminated, the ground fault interference
must be cleared manually. Following this, the Sunny Boy resumes operation.
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SMA America, LLC
Installation Manual