Q: How the electricity generated by PV can be used to give priority to the user's load, instead of the PV power being sent to the grid, and the load is taken from the grid?

A: From the circuit principle, the current flows from the place where the voltage is high to the place where the voltage is low. At the same time, the direction of the current is unique, that is, the current cannot flow in and flow out at the same point at the same time. We use the user-side meter as a node. At the same time, the current has only one direction, either the photovoltaic current to the grid or the current of the grid to the load. Therefore, there is no case where photovoltaic power is sent to the grid at the same time, and the load is taken from the grid.

Q: Why could use the solar power at first?

A: Photovoltaic power generation is a kind of power supply. It can output electric energy and can only output electric energy. The power grid is a special kind of power supply. It can supply electric energy to the load as well as receive power as a load. According to the principle that the current flow from high voltage to low voltage.When photovoltaic power generation, from the load point of view, the voltage of the grid-connected inverter is always higher than the voltage of the grid, so the load is preferentially used for photovoltaic power generation, only when the power of the photovoltaic is less than the load power, the voltage at the grid point will drop and the grid will supply power to the load.