PV power generation is a kind of power supply, it can output electrical energy, and can only output electric energy, and the grid is a special power supply, it can provide electrical energy for the load, but also as a load to receive electric energy, according to the principle that the current is flowing from a high voltage to a place with low voltage, when PV power generation, from the load point of view, the voltage of the grid-connected inverter is always a little higher than the voltage of the grid, so the load preferentially uses PV power generation, only when the power of PV is less than the load power, the voltage at the grid-tied point will decrease, The grid will supply power to the load. Distributed photovoltaic, spontaneous self-consumption, surplus on the Internet, generally to install two meters, inverter out to install a meter, record PV power generation, user side and network to install a two-way meter, user side and network to install a two-way meter, users buy electricity.
In grid-tied feed systems, commercial power supplies are mainly used to build the voltage/frequency/phase of the grid. The grid-connected inverter does not output the voltage, but tracks the phase and waveform of the grid, and only outputs current to the grid, because the voltage of the photovoltaic inverter is higher than the grid voltage. According to the circuit principle, the current flows from high voltage to low voltage, so as long as the photovoltaic energy can generate electricity, it will be sent to the load first.
In terms of load, the load consumes current, which is obtained from the current source closest to itself. Take the roof system, the grid-connected inverter is after the mains transformer, of course, the grid-connected inverter feeds and is used first.
PV and mains power switching frequently, will it affect the inverter or equipment?
Because the light is unstable, for a long time, the power of solar photovoltaic power generation is also unstable, so the electricity used for the load, sometimes can be photovoltaic power, sometimes can be mains power, sometimes can be photovoltaic power and mains power supply at the same time, in fact, this is on the surface. Theoretically, the electricity used by the user is the electricity of the grid, because the inverter has a function that converts the electricity emitted by the components into exactly the same electricity as the grid, with the same voltage, the same frequency, the same phase. This switching process does not actually exist.
