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IEM3255 with summation current transformer possible?

Metering & Power Quality

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Sven_Ortmann
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IEM3255 with summation current transformer possible?

Hello,

is it possible to use the IEM3255 with a summation current transformer?


thx


Accepted Solutions
Bojan
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Re: IEM3255 with summation current transformer possible?

If they are connected, for example, like this, I would set CT Primary to 600A:

7232

See Answer In Context

10 Replies 10
JamesAZZO
Sisko | EcoXpert Master Sisko | EcoXpert Master
Sisko | EcoXpert Master
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363

Re: IEM3255 with summation current transformer possible?

Summation CTs with 5A or 1A outputs work with any power meter supporting those inputs. The meter is blind to what is creating those currents.

Sven_Ortmann
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Re: IEM3255 with summation current transformer possible?

At the customer the IEM3255 with Summation CTs shows only half of the real current.

What could be the reason?

JamesAZZO
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Re: IEM3255 with summation current transformer possible?

The connections - particularly of the primaries into the summation CT may be suspect and you need to think about the proportions and size of the summing. 


As I mentioned before, if it's a true 5A or 1A output, the summation of the induced current must always be less than this. Please provide the make/model - datasheet on the summation CT you are using.

Sven_Ortmann
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Re: IEM3255 with summation current transformer possible?

7227

this is only half of current, and only half power.

7226

its a KUW1/30-200 CT from Janitza

72287229

Bojan
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Re: IEM3255 with summation current transformer possible?

Hi Sven,

This is actually Cable split core current transformer - they should probably have something like this, too:

7230

Best regards,

Bojan

Sven_Ortmann
Commander Commander
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363

Re: IEM3255 with summation current transformer possible?

Hi Bojan,

yes they have a 1+1 but i think the summation does not work.

Bojan
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364

Re: IEM3255 with summation current transformer possible?

If they are connected, for example, like this, I would set CT Primary to 600A:

7232

JamesAZZO
Sisko | EcoXpert Master Sisko | EcoXpert Master
Sisko | EcoXpert Master
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1
363

Re: IEM3255 with summation current transformer possible?

Exactly - Bojan's example is exactly right. It adds up the primaries, the proportions of which need to be added together.


That said - are you using a mix of 1A and 5A CTs going into the Summation CT?

Sven_Ortmann
Commander Commander
Commander

Re: IEM3255 with summation current transformer possible?

Hi Bojan,

you are absolutely right. For 1+1 it sould be set to 400A. For 1+1+1 is should be set to 600A

Thank you very much

Sven_Ortmann
Commander Commander
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363

Re: IEM3255 with summation current transformer possible?

Hi,

no it is only 1+1 or 1+1+1