×
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

SUBTRANSIENT REACTANCE - VERSION II

SUBTRANSIENT REACTANCE - VERSION II

SUBTRANSIENT REACTANCE - VERSION II

(OP)
Only one thing i have to add here , the specific customer is a telecomunication company , and they pay huge attention to the harmonic levels of the generator.
By the way the winding pitch of the generatos is 3/4 .

Is actually X"d affecting directly the harmonics level produced by my generator ?

I'm trying to figure out a reasonable answer for why they need lower X"d values , taking as a fact that  only telecomunication companies have this low x" requirement (their loads are inverters , converters , and other similar telecomunication equipment)

Regards


George

RE: SUBTRANSIENT REACTANCE - VERSION II

I dont think its X"d that affects harmonics level but the winding pitch do. Different winding pitch will affect X"d to some extent.

If in the USA, contact Caterpillar and ask for their EDS 70.4 which is bulletin discussing winding pitches and harmonics. What you want to specify is the correct pitch. In fact you should monitor for what kind of harmonics they have.

For example, 2/3 pitch eliminates triplen harmonics, 4/5 pitch elminates 5th and 6/7 pitch the 7th.

RE: SUBTRANSIENT REACTANCE - VERSION II

Also I might add, that if you are paralleling the gens with the utility supply, which are rich in 3rd harmonic voltages which creates significant 3rd harmonic  circulating currents with generators other than 2/3 pitch.

You have to evaluate your set up. There are other mean to mitigate the circulating current issues, if you need 3/4 pitch for load harmonics.

RE: SUBTRANSIENT REACTANCE - VERSION II

X"d doesn't affect harmonic voltages produced by the generator, but lower X will tend to reduce the harmonic voltages resulting from harmonic producing loads (if this is critical to your application, a detailed analysis would be recommended).

If paralleling multiple generators, the winding pitch should match to mimize circulating harominc current. The Caterpillar article is an excellent reference.

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