SMA Solar Technology AG PV Inverters in Stand-alone Grid Systems
Technical Description SI5048-TB-TEN110340 143
17.2 Use of SB 3000TL/4000TL/5000TL in 60 Hz Grids
The SB 3000TL/4000TL/5000TL do not perform an automatic grid frequency detection.
Switching to stand-alone grid operation using the rotary switch does not change the frequency.
The PV inverters continue to function with a frequency of 50 Hz.
If you want to use the PV inverters in a 60 Hz grid, you must carry out the change from 50 Hz to 60
Hz manually. You can carry out the setting via communication or software:
1. Set the parameter "FrqCtl.hLim" or "Frequency monitoring lower maximum threshold" to "65".
2. Set the parameter "FrqCtl.Max" or "Frequency monitoring upper maximum threshold" to "65".
3. Set the parameter "FrqCtl.lLim" or "Frequency monitoring upper minimum threshold" to "55".
4. Set the parameter "FrqCtl.Lim" or "Frequency monitoring lower minimum threshold" to "55".
☑ The PV inverter is set to a 60 Hz grid.
17.3 Frequency Shift Power Control (FSPC) - Power Adjustment of
the PV Inverter via Frequency
This section describes the operating principles of the power adjustment of the PV inverters via
frequency (Frequency Shift Power Control - FSPC).
If PV inverters are connected to the AC side of the stand-alone grid, the Sunny Island must be able to
limit their output power. This situation can occur when, e.g., the Sunny Island battery is fully charged
and the (solar) power available from the PV array exceeds the power required by the connected
loads.
To prevent the excess energy from overcharging the battery, the Sunny Island 5048 recognizes this
situation and changes the frequency at the AC output. This frequency adjustment is analyzed by the
PV inverter. As soon as the grid frequency increases beyond the value specified by "Fac-Start delta",
the PV inverter limits its output power accordingly.
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