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pietere avatar image
pietere asked

Frequency modulation on multiplus II goes immediately to max

I have a Multiplus-II-48/5000/70. My solar panels are connected to the UPS side. I like my solar invertor to reduce output when batteries are full and grid is nog available to dump extra energy. So i use the "pc invertor support" assistent to change the Multiplus-II output freqency to signal to the solar-invertor to reduce power (frequency modulation).

The specifications for the solar-convertor are:

It starts reducing output power at 50.40 Hz. Output power will be reduced to zero at 50.72 Hz. Disconnect freqeuncy of solar-invertor is 52 Hz.

I have this problem: The multilplus raises the freqency to fast for the solar-invertor to react (or maybe it raises it to disconnect freqency immediately. Not sure because it goes very fast).

Result is that the soloar-invertor is switching off and on all the time.

The solar-invertor is a fox-ess. They Fox-Ess say that the "derating speed" of the solar-invertor is set to 20. They ask if they should make the threshold wider. But i do not exactly know what they mean by derating speed and threshold. Neither can i gave them any new values for these settings.

How to solve. Can anyone help?

Multiplus-IIfrequency
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1 Answer
rikhf avatar image
rikhf answered ·

"They ask if they should make the threshold wider. But i do not exactly know what they mean by derating speed and threshold."

Well from 50.4 to 50.72 seems a narrow bandwidth to me so maybe they should set it wider and you try again.

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pietere avatar image pietere commented ·
Thanks. Would it be possible for you to give me an indication of what a good bandwidth would be for the Multiplus-II?
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