×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Are you an
Engineering professional?
Join Eng-Tips Forums!
• Talk With Other Members
• Be Notified Of Responses
• Keyword Search
Favorite Forums
• Automated Signatures
• Best Of All, It's Free!

*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.

# movement of overhead conductors due to short circuit forces

 Forum Search FAQs Links MVPs

## movement of overhead conductors due to short circuit forces

(OP)
I'm interested in knowing from this group what tools or techniques are available to model the movement of 2 parallel conductors carrying short circuit currents of approximately 3000 to 6000 amperes.  The application is for an electric utility line in which a short circuit occurs between 2 of the 3 phase conductors.

Under these conditions, the faulted wires move apart and, following the interruption of current by a protective device, the wires often swing back together and make contact causing a new short circuit 1000 ft or so ahead of the original short circuit location.

My own efforts to model this situation follows Coulomb's law.  In representing the span of wire, I modeled each of the wires as a pendulum at a length equal to the average sag of the wire.  In an iterative calculation, I start with initial spacing when short circuit occurs.  Then I increment the calculation, the new spacing reduces the repelling force.  I calculate the displacement, velocity and acceleration of the 2 wires and repeat the calculation.

My objective is to start with the normal spacing and see if there's a likelihood of the wires coming together.  If it is likely then I try changing the spacing or height of one to see if that avoids the collision.  A collison means that another protective device operates and makes it a larger area of customers that are affected.

In a more rigorous sense, how could one model this situation?  Since the wire follows a catenary path, can this be represented rather than the simpified way that I did it?
Replies continue below

### RE: movement of overhead conductors due to short circuit forces

Looks like straightforward calculus.  You have the catenary and coulombs law.  Describe the current as a function of time and then solve for position.
I always supposed that wires were set so that physical contact was never possible.

= = = = = = = = = = = = = = = = = = = =
Plymouth Tube

#### 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.

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

Click Here to join Eng-Tips and talk with other members! Already a Member? Login

Close Box

# Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

• Talk To Other Members
• Notification Of Responses To Questions
• Favorite Forums One Click Access
• Keyword Search Of All Posts, And More...

Register now while it's still free!