Contact US

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!

*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

What is Typical with Back-UP DC Wiring?

What is Typical with Back-UP DC Wiring?

What is Typical with Back-UP DC Wiring?

Is it ever done, or even doable, to have the backup DC system be able to run the spring charge motors and MOABs for the blackout failure of the primary DC system?

What is typically for your utilities regarding the backup DC wiring- do you keep the all back up wiring dedicated to the back up relay or do you run the backup trip coil into the primary relay?

For those that use Primary and Secondary schemes vs Primary and Backup, what is typical in terms wiring and control?

RE: What is Typical with Back-UP DC Wiring?

Can you please explain your " back up DC system" ? Are you referencing something different then your standard station battery system for a sub?
A bit confused....

RE: What is Typical with Back-UP DC Wiring?

Basically you have two battery banks. One is the primary battery bank which gives power to the primary relays, primary trip coils, MOABs, spring charge mechanisms, RTUs, HMIs, ect.

Battery bank two is a backup bank which feeds power to the second set of relays and a second set of breaker trip coils.

The idea is if that bank one fails, the second bank will still be able to trip breakers should a fault occur on the system.

RE: What is Typical with Back-UP DC Wiring?

Why would bank one fail?
If bank one failed, what’s stopping bank two from failing? Generally speaking they are maintained the same way at the same time. We have a spare bank at a station. It was purchased with a transformer. The idea was to leave them in there “just in case”. Hasn’t been used in 15 years. Maintained the same as station batteries

BTW, how much is a battery bank and a cabinet? 120VDC or 48 VDC.

Monthly inspections and SCADA generally catch issues before they become problems.

RE: What is Typical with Back-UP DC Wiring?

The worry is a short circuit- hence why the batteries, panelboard main and branch circuits have OCPDs. An unexpected fault or overheated connection could shut down an entire bank.

The theory is that it is unlikely that both will suffer the same contingency at the exact same time if kept reasonably apart; unless of course something like a serious control house fire or tornado touched down whereby total lack of DC power would be a least concern.

Also sometimes NERC or NPCC standards require it.

The to be built drawings aren't giving a price list, but the bank is 125 volts DC.

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! Already a Member? Login


Low-Volume Rapid Injection Molding With 3D Printed Molds
Learn methods and guidelines for using stereolithography (SLA) 3D printed molds in the injection molding process to lower costs and lead time. Discover how this hybrid manufacturing process enables on-demand mold fabrication to quickly produce small batches of thermoplastic parts. Download Now
Design for Additive Manufacturing (DfAM)
Examine how the principles of DfAM upend many of the long-standing rules around manufacturability - allowing engineers and designers to place a part’s function at the center of their design considerations. Download Now
Taking Control of Engineering Documents
This ebook covers tips for creating and managing workflows, security best practices and protection of intellectual property, Cloud vs. on-premise software solutions, CAD file management, compliance, and more. Download Now

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:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close