×
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

3W vs 4W Inverters and Ground vs Neutral

3W vs 4W Inverters and Ground vs Neutral

3W vs 4W Inverters and Ground vs Neutral

(OP)
We are seeing 3W inverters desiring interconnections to the solidly grounded power system from PV systems.  There is an issue as to how does this type of a 3W system perform a phase-neutral voltage protection measurement as required in the 1547 standards etc.  There is a desire of the interconnector to use a bonded 4th wire as the ground/neutral which is not safe.

RE: 3W vs 4W Inverters and Ground vs Neutral

L1, Neutral, L2, Ground. Four wires. Am I missing something?

Bill
--------------------
"Why not the best?"
Jimmy Carter

RE: 3W vs 4W Inverters and Ground vs Neutral

(OP)
The issue is that the ouput of the inverter provides only L1,L2,L3, rather than the more conventional L1,L2,L3,N.  They are bonding the frame to earth and then trying to call that the neutral. This is driven by a PV array.

RE: 3W vs 4W Inverters and Ground vs Neutral

You will need to have delta-wye transformer right next to the inverter to get a neutral for a separately derived, grounded system system.

In theory you can parallel a 3 wire system with a 4 wire system and it becomes a non-separately derived system. You will not able to feed single phase load from the PV system alone, but you can certainly feed power back to the grid.

What is 'desiring" ? They are either made and approved for grid connection or or not. Isn't there a manual with those inverter?

Rafiq Bulsara
http://www.srengineersct.com

RE: 3W vs 4W Inverters and Ground vs Neutral

Any UL-1741 inverter will comply with IEEE-1547 clause 4.1.2.  In simple terms, and three-phase inverter will, within the UL-1741 package, include a delta-wye transformer.  This is a separately derived source and all of the grounding rules for separately derived systems apply.

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