×
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

Relay Curve Types...

Relay Curve Types...

Relay Curve Types...

(OP)
I'm doing an arc flash study using ETAP software. Under one of the relays models (Alstom) there is an option for ieee very inverse curves and iec very inverse curves! I understand that IEEE-VI and IEC-V has completely different trip time equations and hence the time current characteristics are different. How am I to know which to use?

RE: Relay Curve Types...

I would say it would be dependent on which is the accepted standard in your country.  In the USA, I would use the ANSI/IEEE curve.  In Europe, the IEC.

RE: Relay Curve Types...

Are you setting the relays or using existing settings for the arc flash study?  If you are using existing settings, you will have to determine which curves are used in the existing settings.  If you are setting the relays, I'd follow wbd's advise.

RE: Relay Curve Types...

Most of the relays that have multiple curve options only allow either the IEEE or the IEC curves, not both. This data should be available from the relay model number.

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