Solar System With No Battery - Design

I am building a solar system without battery for my home in Thailand based on the attached design. I am using the Growatt spf 5000 es along with 10x450w Trina panels in a 5S2P configuration for this project. I have tested the inverter in relation to GN bonding and found that it does not bond when using AC input. I will revisit this issue if and when I choose to add a battery pack.

The design eliminates the need for a distribution sub/critical load panel by using the main panel. It redirects one phase of the utility-provided three phase supply to the Inverter's AC Input and connects the inverter's AC Output back to the main panel (sort of replacing the redirected phase with itself + some added power provided by the solar panels). This saves me time, money and allows me increase or decrease the load on the inverter within minutes if not seconds.

Potential downsides are inability to supply 3P power for a single load and possibility of complications when adding battery power (maybe not?)

My purpose for starting this thread is to share and receive some feedback on my approach and implementation. All comments welcome.

Thanks
Sam

As I understand, bad idea as the inverter has no way to "time" its phase to be "in phase" with the other 2 provided by the power company.

schmism said:

As I understand, bad idea as the inverter has no way to "time" its phase to be "in phase" with the other 2 provided by the power company.

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Thanks for your comment. I agree but wouldn't that be an issue if I were to run a 3Phase load (like a motor) as opposed to using just one phase? All my existing loads from the main panel is using 1Pole RCBO breakers directed to 1phase loads.

Any loads connected to the 3rd phase and one of these phases is going to be an export issue for grid workers in a grid outage. You need to separate the loads in two different panels.

timselectric said:

Any loads connected to the 3rd phase and one of these phases is going to be an export issue for grid workers in a grid outage. You need to separate the loads in two different panels.

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Thanks for your comment. That would be bad. Just for my understanding if the power company shut down the supply to perform some work, the inverter would supply solar only and current would return to its source which is the inverter thru the neutral line. How does that affect the connected out going neutral line?

diysaa12 said:

Thanks for your comment. I agree but wouldn't that be an issue if I were to run a 3Phase load (like a motor) as opposed to using just one phase? All my existing loads from the main panel is using 1Pole RCBO breakers directed to 1phase loads.

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no, the "single" phase equipment is still tied to 2 legs of the 3. the voltage potential (peak to peak, not RMS) is relative to the phase angle of each of the legs. So if all 3 aren't in "time" then L1-L2 might be abnormally low while L1-L3 would be abnormally high. Both are significant (dangerous) issues.

schmism said:

no, the "single" phase equipment is still tied to 2 legs of the 3. the voltage potential (peak to peak, not RMS) is relative to the phase angle of each of the legs. So if all 3 aren't in "time" then L1-L2 might be abnormally low while L1-L3 would be abnormally high. Both are significant (dangerous) issues.

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Thanks for you reply. So is my only option to go for a 3 phased inverter/3 parallel inverters?

diysaa12 said:

Thanks for your comment. That would be bad. Just for my understanding if the power company shut down the supply to perform some work, the inverter would supply solar only and current would return to its source which is the inverter thru the neutral line. How does that affect the connected out going neutral line?

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Just re read your post. So, you have 3 phase wires and a neutral. All loads are single phase hot (on a single pole breaker) and neutral.
If this is correct, then you should be fine.

timselectric said:

Just re read your post. So, you have 3 phase wires and a neutral. All loads are single phase hot (on a single pole breaker) and neutral.
If this is correct, then you should be fine.

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Yes that is exactly how my main panel is setup. Each incoming phase from the utility is connected with neutral to its own loads via 1pole breakers.

diysaa12 said:

Yes that is exactly how my main panel is setup. Each incoming phase from the utility is connected with neutral to its own loads via 1pole breakers.

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Just make sure that in the future you don't connect any loads to the inverter phase and another phase.
(3 phase motor or single phase using two legs)

@timselectric - Absolutely will not. Really appreciate your time and input!