Wellington horizontal power frequency off-grid inverter

Can sunny island inverters be off-grid?

In off-grid operation, the Sunny Island inverters must be able to limit their output power, if PV inverters are connected on the AC side. This situation can occur when, for example, the battery of the Sunny Island is fully charged and the PV power available from the PV system exceeds the power requirement of the connected loads.

Can I use PV inverters in off-grid systems?

You can use the following PV inverters in off-grid systems. You can order all the listed PV inverters with preset off-grid parameters from SMA Solar Technology AG. The PV inverters must be equipped with at least the firmware version given in the table, or a higher version.

How does a PV inverter monitor the frequency change?

This frequency change is monitored by the PV inverter. As soon as the power frequency increases beyond the value specified in FAC Start Delta, the PV inverter limits its output power accordingly. fAC refers to the base frequency of the stand-alone grid (here 50 Hz).

How much AC power should a sunny island inverter have?

In off-grid systems, the nominal AC power of the PV system must not be more than double the nominal AC power of the Sunny Island inverters. The battery capacity per installed kWp of the PV array must be at least 100 Ah. Example: In a PV array with 5 kWp, the battery capacity must be at least 500 Ah.

What happens if an elevator motor enters the off-grid inverter?

Because the motor will reverse when the elevator is descending, a counter electromotive force will be generated. When it enters the off grid inverter, it might damage the inverter. If a PV off-grid system is required, it is recommended to add a frequency converter between the inverter and the elevator motor.

Can a wind power inverter feed into a stand-alone grid?

If wind power inverters feed into the stand-alone grid, design the total nominal power of the AC sources in the stand-alone grid to be no larger than the nominal AC power of the Sunny Island. Allow at least 100 Ah of battery capacity per 1000 W of nominal AC power from the AC sources in the stand-alone grid.