What is anti-reverse and anti-backflow?
First of all, what is ‘reverse current’ of electricity? In the power system, electricity is transported from the grid to the home, known as the forward current. When we install a balcony power station in a home, the power generated by the PV system is greater than the power of the home load, the power that is not consumed is sent to the grid, which is called ‘reverse current’ because the current is in the opposite direction. To prevent the excess power generated by the balcony power station from flowing into the grid is to prevent backflow.
Why should I install a balcony power plant with an anti-reverse current function?
Reason:
a.The capacity limitations of the upper transformer level prevent new additions to the grid locally, but there is still a demand for the installation;
b.For some regional policy reasons, grid connection is not allowed, and once a reverse power feed-in is detected, the grid company will impose a fine;
c.When too much power is fed into the grid at the same time, it will not only lead to degradation of power quality, but also cause some electrical failures as some wires are too old.
How do balcony power stations and microinverters achieve backflow prevention?
PV backflow prevention system can be divided into single-phase backflow prevention system, three-phase backflow prevention system and energy storage system. The principles of single-phase and three-phase backflow prevention systems are the same.
a.Install CT current sensor at home grid connection point, when CT current sensor detects current flow to the grid, it will feedback the detected data to PV HUB, PV HUB responds quickly and reduces the output power until the output power of the inverter is nearly equal to the load power, and the reverse current is zero, so as to realise zero-power Internet access.
b. Installation of energy storage device: install a meter or current sensor at the grid connection point, when detecting the current flow to the grid, the output power of the micro-inverter will remain unchanged, the PV HUB will store the extra power in the battery, and when the power of the balcony system decreases or the power of the household load increases, the PV HUB will control the battery to supply power together.
