×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

short cicuit data from client

short cicuit data from client

short cicuit data from client

(OP)
I am doing a short circuit study for a system. The fault level on 28KV side is, R1= 6.78727 OHM, X1=19.19640 Ohm.

On the SLD, it also shows that, R1(pu)=0.6787pu, X1(pu)=1.7196pu.  100MVA base

The above data doesn't make sense to me. The short circuit current derived from the above data.

RE: short cicuit data from client

(OP)
I just confirmed the data. The per unit data is right and the system source is very weak. From down sream, we have 40% loads are VFD controle, so I am really concerned about the harmonic distotion effect.

I am wondering if there is rule of thumb to calculate harmonic portion. or I have to run ETAP software.

RE: short cicuit data from client

Check and see if the VFD's have filters.

Mike

RE: short cicuit data from client

(OP)
My lead told me that if we took out filters from VFD, VFD would be more expensive. That doesn't make sense to me.

RE: short cicuit data from client

I'm certain that a filter in a VFD will cost more than one without.

Mike

RE: short cicuit data from client

The lead was probably refering to a 18 pulse VFD vs a 6 pulse.  The 18 pulse VFD would help with curbing harmonics.  He was probably saying it was cheaper to put filters on a 6 pulse VFD rather than buying a 18 pulse VFD.

Maybe?

Jason

Jason Buda, PE
Greenville, SC
jbuda54@yahoo.com

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources