question

Paul B avatar image
Paul B asked

Does anyone have a Assistant that will let me action a relay AC1 IN when a specified Hz figure arrives

Community assistant requested.

I am looking for a assistant that will action a relay, if the Hz raises to a set figure

Ie I have a grid Tie inverter connected to the AC1 out of a multiplus 48/5000 and I am wanting to export power if my batteries are full and before the Grid tie inverter shuts down, I want to turn on AC1 In so that power is then exported. instead of being lost


I have currently got the AC1 in to be ignored and am using gen autostart to turn the AC1 on if the battery voltage drops to say 50v and off again when it raises to 53v

this works well and the AC1 in will charge the batteries if we get a cloudy day but not fill them unless the solar comes in etc


So then if the battery is full and all loads are covered then the grid tie is going to be turned off or down, I am looking for a assistant that will turn on AC1 if hz gets to say 51 hz then off again after a set time period say 1 to 6 hrs so that I can export the excess power back to the local grid.


basically I am off grid but as we are part of a community power grid it would be nice to send back unused power so that others can use it.

No point in wasting it


I tried negative battery amps in the autostart but a neg number is not allowed

even tried using quite time and setting the voltage but that wont work as well

other suggestion welcome


willing to contribute to the cost if someone can make one


Thanks



ESS
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3 Answers
boekel avatar image
boekel answered ·

I'd use another generator assistant, this time starting at 90% SOC (depending on your batteries).

OR use the generator assistant in reverse, so it disconnects the grid above x% SOC and re-connects above y% SOC

btw. why not just use ESS? is the grid not stable enough? You get the same results, but not complete disconnection from grid.

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Paul B avatar image Paul B commented ·

The ESS is ok but its not 100% the Hz config would make it just how I want it.

but then nothing is perfect


and with the Autostart you cant set the stop higher than the start on SOC or voltage

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boekel avatar image boekel ♦ Paul B commented ·

I'm sorry but the Hz config doesn't work.

You want to connect to a grid that is 50 Hz, so the multi has to synchronize back to the 50Hz grid, at the same time the PV inverter will increase it's output while the battery can't handle more input...-and- your Hz config would dropout again as the frequency goes back to 50Hz.

You -can- use the autostart the way you want, you just might have to use it 'backwards'

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screenshot-2019-02-17-124335.png (24.2 KiB)
sean avatar image
sean answered ·

An external frequency dependent relay might be an alternative solution, there's plenty available, here's one.

http://www.comadan.com/produkt/frequency-relay-rf20


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Paul B avatar image
Paul B answered ·

I was hoping that with the hz config say it triggered at 51hz but on trigger it stays on for say 4 hrs then turns off.


example, we are off grid and at 1pm the battery is full and the loads are down but the hz starts to raise to turn the grid tie off, but the assistant, turns the grid on and it stays on then for a fixed time period. this would work. I think the challenge is can a assistant be programed to do it.

even voltage would maybe work as you could catch the max voltage at the battery as it increased over bulk.

are there any instructions around for programing assistants. its a long time since I have programed but am willing to try.


thoughts

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