Grid tie questions

[slowbutsure]

I have a hybrid inverter and I may want to grid tie at some point. I don’t understand the functions of limiters and if I need one.

The inverter has settings to switch grid tie on and off, and the amount of power to send to the grid. But there is no port for a limiter. Can anyone explain (simply) limiters for me and why or why not I need one please?

 

[DIYrich]

The CT (current transformer) measures the amount of power going through a specific wire. If you put the CT just after the Meter, you can determine how much power you are importing/exporting to the Grid. If you are producing more power than you are consuming, the Inverter can detect that, and send the extra power to the Battery instead. Similarly, if you are importing power, it can detect that, and supply power from the battery to zero it out.

 

[slowbutsure]

But my inverter seems to have settings for controlling how much to export so why is the cat needed? And why does the inverter have no way to connect a ct? Really appreciate your help, thanks.

The CT (current transformer) measures the amount of power going through a specific wire. If you put the CT just after the Meter, you can determine how much power you are importing/exporting to the Grid. If you are producing more power than you are consuming, the Inverter can detect that, and send the extra power to the Battery instead. Similarly, if you are importing power, it can detect that, and supply power from the battery to zero it out.?

 

[DIYrich]

There are built in CT's inside the inverter. It can see how much power the Load connection wants and adjust accordingly.

The Sol-Ark 15k can use CT's to measure power pushed to the grid through the input line (grid line). If there are loads between the Mater and the Sol-Ark, then the Sol-Ark can use the CT's to zero out that power usage. Useful when you have batteries and want to maximize self consumption. It only charges batteries after all loads (before and after the Sol-Ark) are supplied. Or, it can use the batteries to supply power to limit power from the grid during high cost times.

It is a nice feature, but not necessary. Especially if you have an inverter that is designed to power only a critical loads panel.

 

[kommando]

Until you detail the exact inverter model you have then only vague answers can be given.

 

[slowbutsure]

There are built in CT's inside the inverter. It can see how much power the Load connection wants and adjust accordingly.

The Sol-Ark 15k can use CT's to measure power pushed to the grid through the input line (grid line). If there are loads between the Mater and the Sol-Ark, then the Sol-Ark can use the CT's to zero out that power usage. Useful when you have batteries and want to maximize self consumption. It only charges batteries after all loads (before and after the Sol-Ark) are supplied. Or, it can use the batteries to supply power to limit power from the grid during high cost times.

It is a nice feature, but not necessary. Especially if you have an inverter that is designed to power only a critical loads panel.

Excellent answer, thanks.

 

[RCinFLA]

Some interconnect utility agreements specify a maximum amount of backfeed power which you must stay under.

Common reason to put CT sense on main input lines coming from utility is to limit back feed power but still be able to backfeed supplement your house loads on main panel breakers not connected to inverter AC output subpanel for full backup. You need to still have utility power present to backfeed to your main panel loads.

 

[slowbutsure]

Some interconnect utility agreements specify a maximum amount of backfeed power which you must stay under.

Common reason to put CT sense on main input lines coming from utility is to limit back feed power but still be able to backfeed supplement your house loads on main panel breakers not connected to inverter AC output full backup. You need to still have utility power present to backfeed to your main panel.

I will read that again later. It went over my head this time.

 

[ricardocello]

I will read that again later. It went over my head this time.

Loss of Mains detection is a critical safety feature that ensures when the grid goes down, you don’t try to power the rest of the neighborhood from your inverters. So if no utility power is present due to outage, those non-critical loads cannot be powered, as they are electrically in parallel with the dead grid. Critical loads on the output of the inverter can still be powered of course, if you have battery/solar.