×
Follow Us
Results 1 to 3 of 3

Transformer (XFMR) Sweep Frequency Analysis

    #1
  1. breny426's Avatar
    breny426 is offline
    NETA II
    Junior Member
    Join Date
    Aug 2019
    Location
    Omaha, NE
    Posts
    9
    Reputation

    Transformer (XFMR) Sweep Frequency Analysis

    I recently performed sweep frequency analysis on 2 pad-mounted, OA transformers. When running the curves through the analyzer it showed "R-HF above limit" for H1-H0 to H3-H0 (both open) and H2-H0 (both open).

    Could someone explain what this means? Unfortunately, there already seems to have been some kind of significant event on this transformer and the customer does not have any previous SFRA results to compare to.

    Thanks!

    Click image for larger version. 

Name:	SFRA R-HF above limit.jpg 
Views:	6 
Size:	199.3 KB 
ID:	566

  2. #2
  3. rofo42 is offline Seasoned Member
    Join Date
    Apr 2018
    Posts
    65
    Reputation
    Quote Originally Posted by breny426 View Post
    I recently performed sweep frequency analysis on 2 pad-mounted, OA transformers. When running the curves through the analyzer it showed "R-HF above limit" for H1-H0 to H3-H0 (both open) and H2-H0 (both open).

    Could someone explain what this means? Unfortunately, there already seems to have been some kind of significant event on this transformer and the customer does not have any previous SFRA results to compare to.

    Thanks!

    Click image for larger version. 

Name:	SFRA R-HF above limit.jpg 
Views:	6 
Size:	199.3 KB 
ID:	566
    If Iím understanding you correctly, two different transformers with the same problem? One or both had a fault condition?

    What did the other non sfra tests look like?

    I havenít seen that before but usually if I encounter an error or bad line, itís a test connection issue. If it is on both transformers, that would further lead me to believe a test connection issue. I searched through all the literature I have and couldnít find anything for that issue. Hopefully someone chimes in, SFRA troubleshooting seems to be some big secret.

  4. #3
  5. breny426's Avatar
    breny426 is offline
    NETA II
    Junior Member
    Join Date
    Aug 2019
    Location
    Omaha, NE
    Posts
    9
    Reputation
    Quote Originally Posted by rofo42 View Post
    If Iím understanding you correctly, two different transformers with the same problem? One or both had a fault condition?

    What did the other non sfra tests look like?

    I havenít seen that before but usually if I encounter an error or bad line, itís a test connection issue. If it is on both transformers, that would further lead me to believe a test connection issue. I searched through all the literature I have and couldnít find anything for that issue. Hopefully someone chimes in, SFRA troubleshooting seems to be some big secret.
    After speaking with the engineers at Megger, they also suspect a ground connection issue.

    The biggest issue with SFRA is that if it was not done when the transformer was new, there is no baseline to compare it to in order to determine if there were any shifts in the physical integrity of the transformer.

Subscribe

Login or register to leave a reply!


Share this thread

Related Topics

  1. XFMR test question - wye-delta TTR
    By dbryce89 in forum NETA Level 2 Exam
    Replies: 18
    Last Post: November 4, 2021, 09:12 PM
  2. PI test on xfmr?
    By jfoster in forum NETA Level 3 Exam
    Replies: 0
    Last Post: April 30, 2021, 02:35 PM
  3. alternator frequency????
    By lester mcmanaway in forum NETA Level 3 Exam
    Replies: 7
    Last Post: February 1, 2019, 12:05 AM
  4. demagnetizing a XFMR
    By jaycee91 in forum NETA Level 3 Exam
    Replies: 5
    Last Post: January 23, 2019, 01:33 PM

Tags for this Thread

Follow us


Explore TestGuy


NETA Certification Training


NICET Electrical Power Testing


Help and Support