Sunny Boy 700
Technical Description
SB700-11:EE
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15
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SMA Regelsysteme GmbH
The value of the grid impedance measured at the Sunny Boy is the total of the im-
pedance of the public grid and the cabling impedance in the house (from house dis-
tribution to the Sunny Boy). Excessive increase of grid impedance through the con-
nection cable to the inverter therefore has to be avoided.
Keep in mind that the cable between the Sunny Boy and the house distri-
bution increases the impedance (see chapter 3.3.1,”Connection to the
Electricity Grid”).
The MSD regulations require a type verification and test by an independent certified
testing association. It is also required that the supplier of the inverter tests every sin-
gle MSD before delivering the inverter to the customer. For the user this means:
•
The intensive testing of the disconnection device by the electricity company and
the installer and
•
periodic checking of the disconnection device, legally required previously, are
not necessary anymore.
The redundant design of the MSD and the regular self test on startup allow the user
to get along without periodic tests. Each startup includes a function test in order to
make sure that the allocated switching devices (transistor bridge and relay) are oper-
ating. The self test is repeated in case the test result was negative - if the failure per-
sists the device must be checked by a qualified technician. The failure is indicated by
a warning LED meaning that the inverter is not feeding electricity to the grid. The sys-
tem shutdown because of MSD malfunction cannot be reset with external signals in
order to ensure that the device is checked and set up for grid feeding only by quali-
fied personnel.