question

Rob Duthie avatar image
Rob Duthie asked

Multiplus II - Performing strangely with NZ grid ripple control

Re a Multiplus 2 when in ESS mode, when the grid operator send out the Ripple control signals the inverter will pull up to and extra 1000watts of power when the loads are running at less than 100 watts. the ripple control frequency is in the range of 375 or 500 and up to 1000 Hz in New Zealand.

I though the inverter would have some sort of 1st fundamental filter, so to block all other frequencies , so the inverter can't pull more power very odd fault to react to the ripple control signals, sometimes this can go,on for more than 5 min. 2 or 4 times a day.

The ripple control signal is making the inverter self consume power.

Note: a inverter should not do this !!! a Flaw in the design?

Multiplus-II
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4 Answers
Guy Stewart (Victron Community Manager) avatar image
Guy Stewart (Victron Community Manager) answered ·

That is a strange issue indeed, but I am not sure that I understand.


You are saying that on the grid generated ripple frequency the inverter draws an extra 1000W but the loads are only 100W, where does the extra 900W go?

I don't think it is possible for the multiplus-II to draw, self-consume and dissipate 900W of heat for very long without a thermal overload. It is 90%+ efficient, so designed to only dissipate ~300W at a 3kVA load.

Perhaps it only appears that way and there is an error with the reading, but there is no actual additional current being drawn.

If you could do some more testing and get some more information, perhaps we can narrow it down.

Can you get an independent clamp meter reading to make sure that there is actually DC amps being drawn from batteries/solar?

Do you have the DRM features of the multiplus enabled?


What happens if you switch off all loads for the property at the circuit breakers, does the inverter still continue to consume?

Are you sure there isn't something that is ripple controlled and the inverter is just suppling the load to that?

Or perhaps the location of an energy meter needs to be checked, as that is now seeing an additional load?

Are you physically hearing the inverters transformer load up and hum, or is this an observation from a Venus-device?

We will know more if you can take some more readings of the site.

In Australia, I have seen no issues or interference with the ripple control.

1 comment
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Rob Duthie avatar image Rob Duthie commented ·

Hi Guy

Did you managed to find a answer from your technical people about this issue.

It is flaw some were that should be looked at.

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Rob Duthie avatar image
Rob Duthie answered ·

{Comments in curly bold brackets}

You are saying that on the grid generated ripple frequency the inverter draws an extra 1000W but the loads are only 100W, where does the extra 900W go? {Internal in the inverter self consumption}

I don't think it is possible for the multiplus-II to draw, self-consume and dissipate 900W of heat for very long without a thermal overload. It is 90%+ efficient, so designed to only dissipate ~300W at a 3kVA load.{ will it does with the ripple control signal}

Perhaps it only appears that way and there is an error with the reading, but there is no actual additional current being drawn. {Yes real Amps are drawn battery takes a nose dive in voltage}

If you could do some more testing and get some more information, perhaps we can narrow it down. {It does it every time they sen the ripple done the line}

Can you get an independent clamp meter reading to make sure that there is actually DC amps being drawn from batteries/solar?

Do you have the DRM features of the multiplus enabled? {No}


What happens if you switch off all loads for the property at the circuit breakers, does the inverter still continue to consume?{Yes}

Are you sure there isn't something that is ripple controlled and the inverter is just suppling the load to that? { I turned off the loads to watch it}

Or perhaps the location of an energy meter needs to be checked, as that is now seeing an additional load? {It is after the inverter it self}

Are you physically hearing the inverters transformer load up and hum, or is this an observation from a Venus-device? { yes you can hear it change in tune hum}

We will know more if you can take some more readings of the site. {My site is on the VRM if you look at the data i will send you the link to access it}

In Australia, I have seen no issues or interference with the ripple control.

{This is New Zealand we have all sorts of ripple relay control here, Note My site is a test site for your inverters for evaluation for clients} Send your email address and i will send the VRM access email raduthie@gmail.com}

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Rob Duthie avatar image
Rob Duthie answered ·

Hi Guy

When i have no loads on the outputs, when they send the ripple signal, the battery amps, measured with a current clamp the current follows the screen current and they pulse the ripple signal.

I am a electronics electrical engineer, so i know a little about inverters, and harmonic currents and filters etc.

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mvader (Victron Energy) avatar image
mvader (Victron Energy) answered ·

Hi Rob, Guy asked me to look at this.

Answer is yes: we are aware of it and working on a software fix. Wont be finished before Christmas though; more news in the new year.

Sorry for the trouble!

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Rob Duthie avatar image Rob Duthie commented ·

Hi

Thanks for reply back, so there is a issue with ripple control signals affecting the inverter,

as i have my site is a test site for the Mulitplus 2 unit. i can live with this fault for the time until your software engineers find the solution, as i don't wont to supply these units with odd software faults cropping up and clients asking questions why ?

I have wired the energy meters in away to read the correct flow of power as the way your manuals go about it doesn't work correctly with the Mulitplus 2 Units.

So far i am finding the unit quite interesting in its operation.

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Rob Duthie avatar image Rob Duthie commented ·

Hi

Just an update on this fault. Some day's at moment if can pull over 2000watts when the ripple control signal is sent out over the network.

Updated to the version 2.23 on the Raspi display unit.

I have used versions 2.30-24 before the version numbers changed down to lower ver numbers. I soon will update the version number to 2.30-31.

When testing these version numbers i have not noticed any difference in performance or odd happenings etc.

Regards

Rob D

Rotorua

NZ

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