4 Power-Generating Unit Protection Test
SMA Solar Technology AG
Service Manual for Installers
SC-UP_SCS-UP_EZE-SG-en-10
14
4
Power-Generating Unit Protection Test
The power-generating unit protection test is a fundamental part of PV system certification. For existing systems the
protection test is part of the certificate, for new systems it is part of the declaration of conformity. The power-generating
unit protection test helps grid operators and the certifying body to understand the proper parameterization and
function of the protection concept. To this end, the test procedure must be documented completely. The
parameterization specifications and the accuracy class requirements can be found in the grid connection guidelines or
are specified by the grid operator.
4.1
Safety during the Power-Generating Unit Protection Test
DANGER
Danger to life from electric shock due to live voltage
High voltages are present in the live components of the product. Touching live components results in death or
serious injury due to electric shock.
• Wear suitable personal protective equipment for all work on the product.
• Do not touch any live components.
• Observe all warning messages on the product and in the documentation.
• Observe all safety information of the module manufacturer.
• After switching off the inverter, wait at least 25 minutes before opening it to allow the capacitors to discharge
completely (see Section 3.1, page 11).
4.2
Calculating the Reference Voltage
Contractually agreed voltage V
C
corresponds to parameter VolRtg
The contractually agreed voltage at the grid feed-in point V
C
corresponds to the parameter
VolRtg
. V
C
– the
voltage contractually agreed on with the electric utility company – must be entered for the parameter
VolRtg
during commissioning and calculation of the reference voltage.
An appropriate reference voltage must be selected for the testing device when performing the protection test. The
reference voltage can be calculated using the following formula.
Formula Symbol
Unit
Explanation
V
0
V
Reference voltage of testing device
V
C
V
Voltage at the grid feed-in point, contractually agreed with the grid op-
erator
i
-
Transmission ratio of the MV transformer. The transmission ratio is the
ratio of
TrfVolExLo
to
TrfVolExHi
.
VolRtg*
V
Nominal line voltage of the utility grid (parameter)
TrfVolExLo**
V
Voltage on the low-voltage side of the external transformer (parameter)
Summary of Contents for SC 4000 UP
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