13.7
Grid Protection
The order option "Grid protection" allows for voltage and frequency monitoring of the utility grid and disconnection of
the inverter after a grid fault. This order option is independent of the grid monitoring function integrated in the inverter.
For this purpose, a voltage and frequency monitoring relay is installed in the subdistribution of the MV Power Station.
The relay is connected to the transformer for internal power supply and measures the power frequency and the grid
voltage on the low-voltage side of the system.
If the measured values for grid voltage and power frequency exceed the set grid limits, the relay disconnects the
inverter via the fast stop input. The grid limits are set in accordance with the "Engineering Recommendation G59/2" by
default (for information on changing the configuration, see the documentation of the voltage and frequency monitoring
relay).
The VMD460-NA from Bender GmbH & Co. KG is used as voltage and frequency monitoring relay.
13.8
Low-Voltage Meter
The order option "Low-voltage meter" allows for recording of the inverter feed-in power and recording of the power
consumption of the entire MV Power Station. For this reason, up to three low-voltage meters are installed in the station
subdistribution. The low-voltage meters measure the values by using the voltage converters and current transformers.
Low-voltage meter for
Required transducers
Measuring the feed-in power of
the inverters
Two current transformers and two voltage converters are installed for each in-
verter. The transformers and converters are connected to busbars of the corre-
sponding inverter (for information on wiring, refer to the circuit diagram).
Measuring the self-consumption
of the MV Power Station
Four current transformers with voltage tap are installed. The transformers and
converters are connected in the station subdistribution downstream the main
switch (for information on wiring, refer to the circuit diagram).
Each low-voltage meter communicates via the serial RS485 interface and Ethernet (for operating information, refer to
the documentation of the low-voltage meter). Laying the communication cables is within the responsibility of the
customer.
The UMG 604E from Janitza electronics GmbH is used as low-voltage meter.
13 Function Description
SMA Solar Technology AG
System Manual
MVPS22JP-SH-en-11
212
Summary of Contents for 1000-1SC
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