What is grid tied and how is this different?

[Frank in Thailand]

Explain it to like I'm a 6 year old.

I have several hybrid inverter who work in parallel and all is great, off grid.

My friend bought the same type, he has (3 phase) 230v grid
(No American setups)

Basic wirering goes OK,
Each phase into the inverter , the inverter has solar and battery and spits out its rated max 5500 watt to the house.

There a part is used as real 3 phase, and some parts as one phase 230v.

So far so good.

His total power usage is never above 13kw.

Here is the catch..
It's not divided equally.

Sometimes one inverter needs to provide more then 5500 watt, and the resettable fuse stops all power

Strange thing, a friend of him, has a growatt, single phase, that can use the grid if they use more then the rated capacity.
Installation by a company, and I don't know nothing about how they did it.
I know they probably aren't feeding the grid (not profitable in Thailand)
That's all.

Our inverter the grid in goes via the mainboard, and understandable can't cope with 8kw, when build for 5.5kw.

Energy still needs to pass via the mainboard, it's just too much.

I don't blame the inverter for limit the maximum capacity to 5.500, via grid or self made from solar or battery.

How does the Growatt do this?
Bypass it's own limitation?
Is that grid-tight?
And no brown/black out function?
I don't know!

Main reason for the inverters, are the frequent brown/black outs.
And large fluctuations in the grid voltages.

Is it possible to wire In a way that the grid will help when the inverter isn't powerful enough to deliver the energy??

And if it is, scematics please!!!

I'm not a total noob, throwing in professional terms that I need to translate to try to understand what the heck you are talking about...
Doesn't work.
Better explain what the term is

Thank you all!!

He doesn't want to feed the grid, just be able to use as he is used to do with the grid, except limited due the power problems from that same grid.

If you understand what I try to say ?

 

[XO4001]

Not familiar with any of your inverters.
I think we can seperate 3 kind of inverters 1/grid tie 2/of grid 3/hybrith.
Hybrith can do both grid tie and off grid.
The difference is when, in grid tie mode the inverter is connected to the grid and synchronize with it so when the inverter cannot supply the needed power the grid will supply what is needed.
When in off grid mode the inverter is only providing what it can no supply from the grid and no synchronizing.
There must be 2 outputs on the inverter grid tied and off grid or load.
If you don't want to feed back to the grid this is mostly accomplished with CT's on the incoming grid power line's when in grid tied mode.
Not a professional just a DIY hope this make sense.

 

[time2roll]

A grid-tie inverter is designed to back feed the grid to run the electric meter backward.

I don't think this inverter is a grid-tie inverter as there would be no connection into the inverter. If you are connecting power into the inverter it is a pass through inverter fed by the grid. These will have power limits as you have experienced. Or if the grid is down one branch could be overloading the inverter.

If you have a single branch that is being overloaded I would look at rebalancing the loads in the distribution panel.

A link to the inverter in question would be helpful.

 

[Frank in Thailand]

The inverter is not a single unit 3 phase inverter, but 3 single phase used as 3 phase.

Brand Sorotec, type Revo-II

It's not somuch about the brand, there are hundreds of different models out there that are on/off grid type, and can do parallel setups.

Some of them can do 3 phase, others just incase the maximal capacity.

All of those on/off grid hybrid inverter seems to have the same setup for wirering:

Grid Power goes into the unit, and the power out goes to the house.

With automatic result, that it's capacity is more or less also the maximal capacity that output with, or without grid.

You can't just pull 10kw out of a contact thayt was designed for 5Kw.
(Extreme example)

Yet, I know there are inverters who can do this, use the grid to feed the "missing" power
(In this example the grid is capable of delivering the 10kw, all cables are thick enough..)
I'm not sure if they are the grid tied type, or also have backup power from battery.

And ..
If they are grid tied, how would one prevent feeding to the grid??

Wirering setup must be different.
Energy can't pass via the inverter, as it's not build for it.
How do they do this??

I'm not talking about units that have power factor of 0.8, and are capable of delivering 1 output via the grid.
5000VA with PF 0.8 is a 4000 watt inverter.
5000 VA with PF of 1 is a 5000 watt inverter.

That 4000 watt inverter can "boost" to 5000 with help of the grid, but is still limited to it's original 5000VA. (Or watt)

The people form Sorotec made a nice YouTube but that doesn't help.

In this video it looks like there is just one cable going from the grid to the Revo and back, with the house still connected to the grid.

Realistic, the power goes into the Revo, and via the unit to the house.

More or less disconnect the house from the grid, where the Revo is the gate keeper.

While this is good...
It helps to keep the grid in the house stable.
The grid itself has high fluctuations in voltage (15%)

That already burned a lot of equipment...
So the Revo also works as stabiliser for the house.

Not sure if it's even possible to get extra from the grid, when it needs also to act as buffer.....

 

[time2roll]

The inverters that combine power with a sine wave source keep track of the incoming power. The inverter only adds to the utility power if the input limit is reached.

My home grid-tie inverter connects to the bottom of my main house panel. The utility power comes in the top. Both feed the panel. Inverter produces full available power regardless of consumption. If consumption is less, the power goes into the grid and the meter runs backward. If the consumption is greater than what the grid-tie inverter can produce, power comes in from the utility. You don't have this type.

You have a hybrid inverter. The little video in your link actually explains it fairly well. Have you looked at the app and review the programming for power priority. I assume with three phase power there are three connected. If more power is needed you can add three or six additional units. May require more solar and more battery.

First I would map out the primary loads to see if something can be rebalanced. Single phase, split phase, 3 phase, it is all about the same once you get your head in it.

 

[Frank in Thailand]

Yes, we can program the power priority.

But.. it's limited to the maximum capacity of the inverter.
With priority Grid, it's still 5500 watt per unit.

Feeding back to the grid isn't a realistic option here, it will cost a lot to get the paperwork ready, and will take years to pay just those cost back, as they pay 25% and don't deduct from your usage..

Load balancing is the key, sadly his house is nice wired, without real option to re-wire without redoing most of the house.

(The installer did not leave any space in the cable to place it at any other location (welcome to Thailand) it would need additional panel on top of this panel to be able to do, extend each cable...
Not a preferred option)

Most simple option is to add more units, not a problem to add.

Maximal 9 units, that can be 3 X 3
In his case, 3 X 2.
He has one spare, so just needs to buy 2 more.

His original information about how much power he is using was not correct enough with real life.

Funny thing is, for me (I live off grid) the inverter goes into overload, beeps for a few minutes, fans at full speed, and it restarts again.

For him (probably due priority Grid), the resettable breaker snaps.
With result... You need to go to the unit..
And manually reset.

 

[time2roll]

The app should have a setting that will limit incoming utility power to avoid tripping the breaker. I would assume the inverter would then supplement power from solar or battery for the temporary high usage. I don't know this inverter specifically, however that is how the other hybrids work such as Victron Multiplus and Magnum. Or output could be limited and the only option is adding additional parallel units.

 

[Frank in Thailand]

Yeah...

It's not a really fair comparison.
He has 2 X 7 345w panels, planning is 6*7 panels.
14 (2*7) to each unit.

He has "some" battery, 4 old small lead acid car battery just to get a look and feel about the setup.
In the planning is minimal 50kwh @51.2v LiFePO4.

So, he is crippling the system, and the only way to give the power he request is via the grid...

I have no grid.
My 3.200w units can overload to about 3.8 4.000 watt for about 30 seconds before they go into protection mode.

For him, 6.4 / 6.500 watt.
BUT (!) As there is not enough solar or battery... Al goes from the grid.

(Not strangely enough, most of the time the problem occurs is at night)...

I don't know why he doesn't want to buy the battery.

I provided him with excellent seller, local, BYD 24v 260A laser welded and all, with BMS, active balancer etc. All ready to go.
(He would be buying 8 or 10 of those untis)
Price is really good..
(Thailand only) roughly $2150,- for "48v" 260, S16 with BMS and active balancer..)

Yet...
He keeps "playing", and finds new hickups, what are mostly due lack of equipment... Like 2 units with solar or virtually no battery ...

I'm not sure if any brand would live up to their name if they're handicapped like this...

 

[Cheap 4-life]

grid tie inverters can supply their max output to the main panel and at the same time main panel loads take however much more remaining power they need from the grid-main panel. Grid tie inverters do not pass through the grids power to loads. The just supply what they can. Some grid tie inverters can also use batteries. Some grid tie inverters also use external CT sensors to limit the amount of power they produce to only what the main panel loads are needing. I’m using GTIL2 inverters that do as I explained. For 3 phase one 1kw GTIL2 outputting 120v can be used on each phase. I’d be really interested if there was a growatt that can do these things.

Most hybrid inverters say they can also do grid tie operation. From what I read they can only allow loads to use grid power by passing that power through themselves at a limited amount. Maybe Solark and outback skybox can operate like I explained in the first paragraph when they are in grid tie mode. I hope they can. They cost enough, they should not need to pass through grid power to the loads they are powering if the loads need more than the inverter can supply.

 

[Frank in Thailand]

If I understand correctly, grid tied with battery option is more or less the only setup that can support higher capacity loads then rated capacity of the units.

Almost all hybrids are limited to their capacity, while they might have more available from the grid, you should use the automatic Failover Switch to disconnect the hybrids, and use the grid to full capacity when you really need to use more, then the units are rated for.

(That would be if you temporary need to use a lot of energy, far more then normal usage)

If it's regular, one should make sure to have the capacity per leg that will maximal be used.

With rule of thumb, 80% load for continuous use, that number should be the 80%.
Peaks of 8000 need 10kw inverter
(We all know how the usage keeps creeping up, when we add more stuff to the house)

Thanks for helping me understand!!!

 

[Cheap 4-life]

No, all grid tie inverters will supply their max output and loads simply take the remaining power they need directly from the main panel