Each phase of each inverter

[joaa]

Hello,

I have three split inverters, each of which must be linked to a phase since my distribution electrical board is a three-phase system. When the technician informed me that I needed to swap one inverter, I asked him how a phase could recognize it. He informed me that an inverter detects three parameters from a phase:
1- frequency
2-voltage
3-angle
Could someone please elaborate?

 

[JCSchwarb]

Lots of good info online. Check out https://www.astrodynetdi.com/blog/3-phase-delta-vs-wye?hs_amp=true

 

[RCinFLA]

The three inverters get phase locked by interconnecting sync info. Usually one takes the role of master.

When connected to a three phase grid it is important to initially have the inverters assigned to a specific phase. This is usually automatically done when inverters sync to grid.

On three phase separate inverters setup it is important the inverters are assigned so they will match the connected grid phase order. Off grid, the three inverters can decide their own phase order but when grid shows up while the inverters are running they cannot swap which one has the second and third phase offset so there will be an issue of allowing connection to grid.

Some inverters have a method on assigning a three phase offset and you must wire the inverters to proper grid input phase. Check their manual to be sure how this is done on a given inverter.

The issue is similar to wiring a three-phase motor. Swapping two of the phase wires will cause the motor to run in the opposite direction which is usually undesirable (like running a saw blade in wrong rotational direction).

Usually the instructions say to do a grid sync immediately after inverter power up with no external inverter loads applied. This allows the inverters to establish their phase order by the grid phase they are connected to and will keep that order when they are off grid.