My analysis is attached... Thank you for your feedback! http://files.engineering.com/getfile.aspx?folder=55952424-62a4-4a6b-ae53-27e5c7c0c81c&file=Transformer_HV_Line_Current_Analysis_for_LV_Through_Faults.pdf
Hello everyone,
I was reviewing through faults on the LV side of a non-standard delta wye transformer connection. My intention was to understand how the HV line currents would flow based on the type of secondary through fault…
The Delta side of the transformer would be connected...
Hi all,
So I have a dumb question... For a DAC Wye-grnded transformer (Dyn11) with ABC positive sequence rotation - It's very easy for me to see that the secondary line current lags the primary line current by 330 degrees. Or in other words, the secondary line current leads the primary line...
Thank you all for your input! It is much appreciated [bigsmile]
Here is another question to further my understanding - for a lightly loaded transformer where the magnetizing current as a percentage is pretty comparable to the load current, would 3rd harmonics (generated by magnetizing current)...
Can harmonic problems arise (particularly 3rd harmonic) for lightly loaded distribution transformers connected Delta Wye-grounded? I've gone through several sources but couldn't find anything substantial on this particular topic... Thank you in advance for your comments!
you might also want to consider higher rated bushing CTs due to high X/R ratio'd faults near GSU.
http://GeneralPAC.com - Awesome video tutorials for power systems PAC!
The Wye Wye Transformer Connection video: http://gpac.link/1GdGRSQ
I'm glad the videos are helpful :)
@surefire01 - I'm using a Wacom Intuos tablet, Inkscape graphic editor, Camtasia video editor, and Blue Yeti microphone. I spent countless hours experimenting with different hardware, software, and audio equipment until I found the perfect match for me.
I created a series of videos for myself to explore and intuitively understand current transformer. Check out http://gpac.link/1EmY2tV ... associated impedances of a CT, the CT burden, and how the secondary voltage relates to CT saturation is discussed. Hope you find it useful!
I appreciate the feedback stevenal. This is definitely a Yd11 connection. The primary phase current leads the secondary phase current by 330 degrees. :)
I've clarified this in the description section of the video. https://youtu.be/UXVRRLApuuw?list=PLqJ0Y2s60r-56DASDtoqOklamWvJx-mmi
Thanks again!
In an effort to document my learning and share what I've learned, I created this video tutorial on Delta connected CTs --> https://youtu.be/UXVRRLApuuw?list=PLqJ0Y2s60r-56DASDtoqOklamWvJx-mmi -- What do ya'll think?
Thank you everyone for helping me understand!
http://GeneralPAC.com -...
@waross, would you be able to draw this connection? You've got me curious :)
http://GeneralPAC.com - Awesome video tutorials for power systems PAC!
The Wye Wye Transformer Connection video: http://gpac.link/1GdGRSQ
While doodling delta connected CTs on engineering paper (we've all done this), I realized that the CT secondary line current which is going into the relay input terminal has no return path back to the CT secondary circuit... the line current just goes to ground. There is no circulation of line...
It is progressively difficult to be out there in the field especially on call... As you get older and have children, this may not be ideal for you. That's certainly a loaded response with many dependencies. It really depends on your personality etc etc...
I would advise to stay in the field...
@111R,
I think it's important to have an intuitive feel for symmetrical components. I wrote this article that attempts to provide an overview of symmetrical component: http://gpac.link/175IP7B
I'm planning to write symmetrical component analysis for different types of faults - but who knows...
The ANSI Device Number 64 is for ground detector relay
I don't think there is a "phase" detector relay ANSI device number. Otherwise that would make things a little easier. So you'll have to be creative with how you use these device numbers. 64P is a suggestion given the circumstance...
Perhaps a 64P for phase fault detection and 64G for ground fault detection?
http://GeneralPAC.com - Awesome video tutorials for power systems PAC!
The Wye Wye Transformer Connection video: http://gpac.link/1GdGRSQ
Is this for transmission line thermal limits?
http://GeneralPAC.com - Awesome video tutorials for power systems PAC!
The Wye Wye Transformer Connection video: http://gpac.link/1GdGRSQ
@DTR2011,
Can you please point to the Basler application notes/references that you alluded to for Directional OC relay & reverse power protection / detection?
Thanks!
http://GeneralPAC.com - Awesome video tutorials for power systems PAC!
The Wye Wye Transformer Connection video...
