×
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

Delta Zigzag transformer question

Delta Zigzag transformer question

Delta Zigzag transformer question

(OP)
Hi, at my work we got a 70kV Delta-Zigzag transformer that i am currently analysing. The primary side is 3.3kv, the secondary is 400V and the vector group is Dzn0 (Delta-zigzag + neutral(grounded) 0 phase shift). The primary is connected to a generator (wye connected) and the secondary is connected to a diode bridge rectifier with a inductive/resistitive load. Firstly, can the secondary be interpreted as delta or wye with no phase shift. Secondly, what is the purpose of a neutral; has it something to do with the harmonics caused by the bridge rectifier?

RE: Delta Zigzag transformer question

The Delta-Zigzag grounded has the following characteristics:
a)  Suitable for ungrounded source in the generator primary side.
b)  Suitable for 4-wire service in the secondary side.
c)  Suppressed triple harmonic to the generator in the primary side.
d)  At difference of the Wye-ZZG, Delta primary connection does no have phase-shift HV to LV. Therefore, the wye connection cannot be interpreted as equivalent connections to D-ZZG.

Primary neutral grounding in wye-zigzag (Y-ZZ) configuration is not recommended for the following reasons:
•    SLG fault make the primary system vulnerable  since furnish a contribution to ground fault current
•    Coordination of protective devices becomes extremely difficult or virtually impossible due to multiple ground sources.
•    Open conductor faults cause the added duty witch could exceed several time transformer rating.

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