Power control signifies dynamically changing an Inverter's output power based on an algorithm. Wattmon supports dynamic power control using an add-on software package and can be used in conjunction with a power meter for various purposes:
Diesel generator protection
Maximum generation control
Zero Feed - The Why
In India many states experience frequent and crippling power cuts. Solar rooftop systems are springing up everywhere, from small residential houses to large factories in attempt to save costs and in so doing reduce carbon emissions. Many states have not modified their policies yet to allow feed in, which in turn means that all solar generation needs to be used within the premises. This is fine when the installed capacity is much less than the average load, but when a larger solar plant is installed problems can and will occur when loads are less in peak solar hours and during weekends.
Zero Feed - The How
A power meter is installed at the incomer of the building, and is used as a reference to determine the active power load on the building. This meter needs to be able to communicate with Modbus RTU. The Wattmon device is connected to both the power meter and the inverters. It will regularly poll the power meter to determine the active power. As it reaches a threshold value that can be set by the user, it will ramp down the output power on the inverters using power control commands on Modbus RTU. This will effectively limit the amount of generation dynamically so that exporting of power does not happen.
Read more about how power control works on our Wiki.