The inverter adapts its current feed as soon as a drop or spike incident occurs in order to bolster the grid voltage. The
support takes place in the event of voltage drop in the form of over-excited reactive current (corresponds to a capacitive
load), in the event of voltage spike in the form of over-excited reactive current (corresponds to an inductive load). In the
reactive current priority mode, the effective current is reduced to the extent necessary to comply with the limits of the
maximum continuous current of the inverter.
A dip or swell is detected if either the normal operating voltage range setting is exceeded by at least one phase-phase or
phase-neutral voltage, or if a step in the positive or negative sequence component of the voltage greater than the dead-
band setting occurs. The magnitude of the voltage step of the positive and negative sequence voltage equates to the dif-
ference between the pre-fault voltage and the actual voltage based on the reference voltage. The pre-fault voltage is cal-
culated as a 50-periods mean value.
Fig. 55:
Formula no. 1
The reactive current is adapted using a response time of <20 ms and a transient time of <60 ms after the incident has oc-
curred. Responses to changes in the voltage during the incident or to the voltage recovery at the end of the incident take
place with the same dynamic.
The formula for calculating the dynamic reactive current that is fed for the positive or negative phase sequence voltage is:
Fig. 56:
Formula no. 2, depending on the nominal current IN of the inverter
For the positive and negative phase sequence voltage,
Δu
equates to the difference between the pre-fault voltage and the
current voltage based on the reference voltage. The pre-fault voltage is calculated as a 1-min mean value.
Fig. 57:
Formula no. 3
On account of the definition of a voltage jump in pre-norm EN50549-2 and in VDE-AR-N 4120 and VDE-AR-N 4110, it is
typically the case that another voltage jump is detected when the incident is at an end, when the fault is rectified and
when the voltage returns to a normal state. The result of this is that in an active operation mode a dynamic grid support
using a fast feeding of residual current remains active even after the incident has passed and that reactive current is fed
in according to the formulae (2) and (3). Dynamic grid support using fast feeding of residual current is then deactivated
after a configured minimum support time, usually 5 s.
I
b
1
I
Fig. 58:
Formula no. 4
10.3.3
Parameters for FRT
Country-
spec. Set-
tings
Men
u
level
Display/
Setting
Action in this menu/meaning
4
1
2
3
4
FRT (Fault Ride
Through)
NOTE: The device supports dynamic grid stabilization (Fault Ride-
Through)
.
NOTE: More detailed information at:
Operation mode – On
| Off
Settings | Manual |Pre-
defined zero current
Setting: Manual
All parameters can be configured independently.
Setting: Predefined zero current
Dynamic grid support active on account of immunity to interference and
zero current feed-in. During a voltage incident, the current in the in-
verter is reduced to zero.
All parameters are pre-configured, only the activation threshold for zero
current has to be configured.
Powador 30.0-72.0 TL3
Page 65
EN
