LabVIEW Electrical Power Toolkit

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Effect of using an incorrect nominal frequency?

In the EPS there are a few VIs that ask for the nominal frequency as an input:

 

  1. FPGA Code:  In the resampling code there is a polymorphic vi that allows one to switch between 50 Hz and 60 Hz implementations.  There are identical other than using different constants at a very low level vi named fpga_Sine Interpolation.
  2. RT Code:  Initialize System.vi has an input for nominal frequency, either 50 Hz or 60 Hz.  Digging through the toolkit code a bit I can see there are many places where that value is used in a calculation or to switch between different sets of constants.

We have an sbRIO application that is doing various 3-phase power measurements: zero crossing, frequency, harmonics, power & energy values, phasors, etc.  What kind of errors would one expect to see if inputs were set to 60 Hz, but the signals were actually at 50 Hz?

 

Thanks,

Dave

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Hi Daklu,

 

I can't comment on the entire toolkit but:

 

  1. From a 61000-4-30 point of view this is very important since calculations are done over a different number of cycles for 50 or 60Hz (10/12 cycles respectively).
  2. On the FPGA my feeling is you may struggle to get a frequency lock. I think the VI works over very specific ranges in the different modes and if the frequency is out of this range it will never lock onto the frequency. This is a feeling rather than being able to point to hard fact though!

Hope thats a start anyway.

 

Cheers,

James

James Mc
========
CLA and cRIO Fanatic
My writings on LabVIEW Development are at devs.wiresmithtech.com
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Can any one please explain me how to set Sample time in Energy block.
kindly attach .vi file calculating energy from simple simulated sine wave.

It will be great favour 

Thakin you in anticipation

 

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Please don't spam the forums by resurrecting multiple old threads and asking the same question.

 

continue with the post here http://forums.ni.com/t5/LabVIEW-Electrical-Power-Suite/Re-Electrical-power-energy-auditing/td-p/3252...

which I put into its own new message thread.

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