AC Coupling and BYD premium LVL 15.4

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Oliver asked Jun 30, '20

AC Coupling and BYD premium LVL 15.4

Hello,

I would like to know if there is any possible way to speed up frequency regulation by modifying the settings of the PV inverter assistant.

The system is off grid and consists of

- BYD LVL premium 15.4

- Bluesolar MPPT 150/60

- Quattro 48/8000

- Solaredge SE6000H (maximum expected PV-contribution is << 4500W)

The P(f) ramp at the Solaredge side is defined from 50.2Hz to 51.7Hz and disconnect @ 52Hz.

The Victron PV-Inverter assistant is configured for the same band with disconnect @ 52.1Hz. With 6000W inverter and 6400W PV.

I observe that once 55.2V are reached BYD sets the charging parameter to zero. However charging continues as the frequency ramp only rises slowly and therefore the SE inverter does not reduce its output fast enough. For now I throw off (via AC-OUT 2) the SE inverter once the voltage gets higher 57V. By that time frequency has only risen to 50.4Hz. Can the ramp rise time be shortened? Am I too carefull with the 57V limit? (cell details show almost 3.8V for the highest cell). Thank you in advance for your help and input!!

AC PV Coupling BYD

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Answer 1 · 2020-06-30T12:14:49Z

Guy Stewart (Victron Community Manager) answered · Jun 30, 2020 at 12:14 PM

Have you tried with the default parameters that are set in the AC PV inverter assistant in VEConfigure (i.e disconnect at 53 hz).

That should work, and be fast enough.

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Oliver commented · Jun 30, 2020 at 01:09 PM

you mean only changing the disconnect value to its default 53V? The "reduce to minimum" I leave at 51.7Hz as otherwise the SE will certainly disconnect (@ 52Hz) quite often?

By the way, should I have VbatSense of the Quattro connected or is this irrelevant for the regulation (DVCC is selected though)?

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Guy Stewart (Victron Community Manager) ♦♦ Oliver commented · Jun 30, 2020 at 01:10 PM

I would first try with the default settings, and then make adjustments from there once the most important factor (not going over voltage) is sorted.

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Oliver Guy Stewart (Victron Community Manager) ♦♦ commented · Jul 02, 2020 at 06:17 AM

I tried several settings, the one that came closest but still fails in occasions, especially when no AC load is present and battery almost full: SE inverter P(f) ramp from 50.2Hz to 51.2Hz: PV-inverter assistant: 50.2Hz to 52.5Hz and disconnect at 53Hz. Battery voltage still rises faster than frequency. If I don´t control AC Out 2 the BMS of BYD kicks in and produces a spike (66V) which leads to overvoltage (overload) shutdown of the Quattro and frequency lock at 53Hz after recovering. I would prefer avoiding to stress the equipment this way. I will ask in a new post about effects of PV-assistant settings on the generation of the frequency ramp.

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Guy Stewart (Victron Community Manager) ♦♦ Oliver commented · Jul 02, 2020 at 11:52 AM

Am I understanding that the default AC PV inverter assistant settings leads to overvoltage shutdown with your solar edge system?

And similarly, the recommended settings listed here for both the Quattro assistant, and the Solar Edge, also leads to over voltage shutdown?

https://www.victronenergy.com/live/venus-os:gx_solaredge

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Oliver Guy Stewart (Victron Community Manager) ♦♦ commented · Jul 03, 2020 at 09:07 AM

default is: 50.2Hz-->52.7Hz (off:53Hz)

because islanding trip value on SE is 52.5Hz I only tried what is coming close, which is 50.2Hz-->52.5Hz (off:53Hz).

When I visit the site I will modify islanding trip on SE to 52.8Hz and try the default settings and will give you an update on this.

Regarding the Victron documentation "Integrating with Solaredge". What I can confirm is that first: the recommended settings lead to over voltage shutdown. (and don´t work in general)

In one aspect the Victron documentation is not very precise and maybe you could consider correction: please notice that the "text" settings for frequency don´t match the screenshots (50.5Hz against 50.2Hz). Later in the document it says "The same bandwidth needs to be configured on VE.Bus Config for Victron" and here 50.2Hz is the suggested setting. For the SE I assumed the 50.2Hz to be the meant value what needs to be set. Regarding the other settings: I followed them precisely.

In Victron documentation it says:

"Note: APS mode is mandatory for systems requiring both zero feed-in in on-grid mode and frequency shifting in off-grid mode"

I can confirm that power reduction as a function of rising frequency when in APS mode is NOT working. I attach a screenshot (this is with all available PV power in the morning, "power limit" is not reduced, frequency was 51.2Hz and P therefor should be a minimum). On remote console I followed the frequency, power and BatV which confirmed no reduction. P(f) settings in SetApp-->Power Control-->Alternative Power Source are ignored.

When I switch from APS mode back to the default country (in my case Italy with modified islanding values) power reduction P(f) works. I can confirm that power is now immediately reduced when Victron rises the frequency (but then does not gradually increase again when frequency is falling. (it must fall back to 50.0Hz again + some time pass until the power reduction cycle starts again. So P(f) only works in one direction)).

So at this moment I need to use this work around. You see, I am treating with several problems on both ends. I could go more into detail regarding the Solaredge settings, but in this post I want to concentrate on my need to achieve a bit more agile frequency regulation by Victron to avoid overload tripping and I wonder what effect does the inverter power (pv panel power) setting in your assistant have on the speed of the frequency regulation?

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aps-mode-no-pf.jpeg (58.1 KiB)

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