Ghost-current on clamp Zon1

2 day's ago I succesfully installed a flukso-device + 3 clamps. My main interest is metering de power from my solar-installation. It consists of 7 Steca 500 Net inverters in 2 groups (5 and 2) on one powerline that is metered bij a Clamp with the name: 'Zon1'. I have a 1 fase 230 volt installation. I have 2 steca Net-controllers with measured the power of the two Solar groups, but one broke down.

My problem is that clamp 'Zon1' is metering Ghost-current. At night when the steca inverters are sleeping/swithed-off the clamp registered a current of 235 Watt. I checked with an other device the same line and it reads 4-15 watts (jumping) which is consistent with de spec's of the Steca's (should be zero, but okee..). When I disconnect the sub-group of 2 steca's the measured power drops with 50 watts. When I switch the powerline completely off the clamp Zon1 measures 3 watts. I tried installing the clamp on another position, neutral and back to the hot line but with the same results. I switched of the Frontdoor-Bell-transformator that's near the solar-powerline, but the same result. What is clamp Zon1 metering? Can I adjust the result by substracting 235watt from the results?

Best regards,
Peter Veeling.

gebhardm's picture

As the "reactive power" topic pops up from time to time, see also
My learning from this was to not use current clamps for PV measuring but switch to "some S0/pulse capable" meter to feed into the FLM (I currently use a cheap "swissnox" single phase meter for under 20Eur).
Regards, Markus

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Harjo's picture

Just my 2 cents: Markus is right, please read the comments in all other topics. The problem is caused by reactive power, which was proven in my installation last week. I changed my inverter from an SMA1200 to an SMA2000HF. I never had any ghost currents with the old inverter, but now I have a reading of 60W at night. Since nothing changed at my switchboard it is not the clamp placement. It must be the reactive power measurement.
So I probably have to go to a pulse meter, but both pulse ports are already planned to be used for water and gas.... An upgrade to a fluksometer v2b is inevitable.