The solar hybrid system which consists of photovoltaic (PV) and battery storage
can provide electricity supply to the buildings both on-grid and off-grid
conditions. To improve the uninterrupted operation, it is possible to integrate the
grid-tied PV system, without the battery, with the solar hybrid system to enhance
the power generation during islanding condition. However, many hybrid on/off
grid inverters do not allow the other energy sources to charge the battery in the
off-grid mode. A particular power curtailment control is then required for the
grid-tied inverter to prevent the excessive power. In this work, the power
curtailment controller with the combination of smart meter and solar irradiance
sensor is introduced. The set-point of grid-tied inverter is automatically adjusted
following the changes of load consumption and PV power. The performance of
islanding operation among solar hybrid and grid-tied PV systems is examined
based on a time-sweep power flow calculation on DIgSILENT PowerFactory
software. It is shown that instead of using solar hybrid system alone, coupling
with the grid-tied PV system can help increasing the efficiency of battery usage.
Hence, this can extend the continued electricity supply to the building during the
loss of grid voltage.
Keywords
Grid-tied inverter, Hybrid inverter, Islanding operation, Power curtailment, Solar hybrid system