SMA POWER REDUCER BOX - Manual (Page 45)

SMA Solar Technology AG 8 Commissioning
User Manual REDUCERBOX-BA-en-16 45
8.4 Configuring and Activating "Fallback"
"Fallback" is an operating state into which the Power Reducer Box can enter if it evaluates an input
status as invalid.
The Power Reducer Box evaluates an input status as invalid under the following requirements:
• The input status is not configured.
• The input status is not activated.
• The connection between the Power Reducer Box and the ripple control receiver is interrupted
and in addition, the upper constellation of input statues (K1 = 0, K2 = 0, K3 = 0, K4 = 0) on
the "Status configuration“ page is not configured and activated.
The "fallback" prevents the Power Reducer Box from continuing to transmit instructions to the
Sunny WebBoxes in the event of an invalid input status that may no longer be up to date:
If the "fallback" is not activated and not configured, the Power Reducer Box retains the operating
mode of the last valid input status in the event of an invalid input status (e.g. "Effective power control",
"Reactive power setpoint" or "Cos phi setpoint"). If an invalid status is present during an active power
limitation for example, the Power Reducer Box will continue to work in the "Effective power control"
operating mode until a valid input status is again present. If the invalid input status remains unnoticed
over a long period of time, this can lead to yield losses.
If the "fallback" is activated and configured, the Power Reducer Box retains the operating mode of the
last valid input status in the event of an invalid input status for a limited period of time only. How long
the Power Reducer Box retains the operating mode of the last valid input status depends on the time
period that was set for the "fallback". A soon as the set time period expires, the Power Reducer Box
switches to the operating mode that was assigned in the "fallback". In this way, yield losses can be
avoided.
As soon as a valid input status is present, the "fallback" is reset and the Power Reducer Box again sets
the latest requirements of the distribution grid operator.
Time Measurement for "Fallback"
The time measurement begins as soon as an invalid input status is present.
Adjusting settings for the "fallback" during a running time measurement has the following effects on
the "fallback":
If the Power Reducer Box is reset during the running time measurement or the Power Reducer Box is
switched off (see Section 11.1), the time measurement resumes as soon as the Power Reducer Box is
operational again.
Setting Effect on the fallback
• Changing the time interval for the
"fallback"
The time measurement begins at 0. The newly set
time interval is valid.
• Changing the operating mode (effective
power control, reactive power setpoint,
cos phi setpoint) for the "fallback"
The time measurement continues without
interruption. The newly set operating mode is
valid.