Sunny Boy 2000
Technical Description
SB2000-11:EE
- 15 -
SMA Regelsysteme GmbH
The grid impedance is measured by every Sunny Boy just at the place where it is con-
nected to the mains. The measured grid impedance consists of the impedance of the
public grid and the mains impedance in the house (from the house connection to the
Sunny Boy). A drastic grid impedance increase caused by the connection to the Sunny
Boy must therefore be avoided.
We recommend to pay attention to an impedance increase due to the dis-
tance between house connection and Sunny Boy (further information is
given in chapter 3.3.1, ‘Mains Connection’).
The VDEW regulations demand a device test which the inverter manufacturer must
have performed by a qualified certification organization. Furthermore, the manufacturer
has to check the function of the mains disconnection device of every single unit before
delivery. For the owner of the PV-plant this means:
•
The time-consuming disconnection device testing by the electricity company
and the installer is not necessary
•
The previously required periodic tests are not necessary.
Important arguments for the omission of repeated tests are the redundant design and
the recurring self-test of the disconnection device. During every new mains connection
the correct function of the mains monitoring is checked in order to guarantee that the
according switching devices (transistor bridge, relay) are working and able to discon-
nect the load circuit. In case of a negative test result the complete self-test will be re-
peated. If the negative result occurs again, the disconnection device has to be checked
by qualified personnel. In this case the operation will be blocked and indicated to the
user by the LEDs. This operating state will be recorded and cannot be overridden with
simple switching operations from the outside (signals via the serial interface, resetting
the internal computers, switching the device off and on etc.). This ensures that only
qualified personnel can unlock the device for grid feeding after testing the disconnec-
tion device has failed.
