Advanced Grid Features": Lvfrt - Dynamic Grid Backup During Temporary Drops In Grid Voltage; Lvfrt - Function Description - Fronius SnapINverter Serviceanleitung

"Advanced Grid Features": LVFRT - Dynamic grid
backup during temporary drops in grid voltage
LVFRT - Function LVFRT = Low Voltage Fault Ride Through
description (dynamic grid backup during drops in grid voltage in the high voltage and highest voltage
grid in order to prevent an undesirable shutdown of the feed-in power and the collapse of
the system)
Inverters with LVFRT support the grid in the event of a drop in voltage. Grid backup can
occur for up to 1500 ms.
Rather than disconnecting from the grid and having to wait for the defined reconnection
time, the inverter remains active following the grid problem and continues to feed in the full
power.
If required by the grid operator, the inverter can feed in a defined reactive current during
the voltage drop. This is configured by activating the LVFRT function.
Example of a possible LVFRT specification:
Voltage drop up to 0 % lasting up to 150 ms
(2) = Time at which failure occurs
U = Nominal voltage
U
Example for LVFRT - Voltage waveshape limiting curves
-
-
When the LVFRT function is disabled, the inverter does not feed in any dynamic reactive
current if the voltage drops rapidly.
96
= Operating voltage in a medium-voltage network
C
U/U [%]
C
100 %
70 %
45 %
30 %
15 %
0 150
(2)
If the voltage is above the limit line (1), the inverter must not switch off.
Any feeding in of a short-circuit current during a voltage drop must be agreed with the
grid operator.
If the voltage is below the limit line (1), the inverter can be disconnected from the grid.
The inverter is always safely disconnected from the grid according to the set trip val-
ues for the inner and outer voltage limit values.
(1)
700 1500 3000
t [ms]