Understanding Line Distance protection (21)
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- เผยแพร่เมื่อ 6 ก.พ. 2025
- End-to-end testing can appear to be a daunting task. However, any relay tester can perform successful end-to-end tests with a basic a basic understanding of transmission line protection (or 21 impedance protection) along and some preparation before the testing is scheduled to begin.
The second video in our end-to-end testing series continues our introduction to transmission line protection (also called impedance protection, 21-element protection, or line distance protection). We perform a series of end-to-end tests on a normal transmission line with standard line distance protection and compare the results to a POTT scheme to see how standard distance protection is different than communication-assisted tripping schemes.
You can play with these animations at our website relaytraining.com/. Each of the most commonly applied protection schemes have their own animations and they can be found at relaytraining.c....
The standard line distance animation can be found at relaytraining.c....
The POTT scheme animation can be found at relaytraining.c....
This video expands on the descriptions found in The Relay Testing Handbook: Principles and Practice, Testing Line Distance Protective Relays (21), and End-to-End Testing. You can order any of these books in print or as digital pdf downloads at our store (relaytraining.c....
Thank you for all the hard work making these videos available to the public. It is much appreciated.
The best lectures I saw on Distance protection...
one of the best description of this topic
These materials will certainly help me on doing my job.
shortest explanation i ever heard, thank you!!!!
full detail and thorough description, thank you...
Good work 👍
This is a high-quality explanation
Best lecture on 21 relay
It's very clear and understanding for everyone 🙏
Fantastic. Thank you so much for this video.
it’s very useful to understand how distance relay work.
More videos please.
So far so good. Vids 1 & 2 seem very good. I've picked up a few things. Thanks for creating these vids and sharing them!
Very precise and great use of graphics. Thanks for uploading.
+ayush shringi Thanks
Best
Excelente explicación de la función 21. gracias por el video.
Good explanation of POTT Schemes.
Very clear explanation! Thanks. At last, now I understood them.
I wish our professor showed us that video in class.. Now I clearly understand what he was talking about
Plz make more the videos like this, i love it! Thank you
Deep Informative .. Simple Explanation .. Thanks For Sharing .. Keep Going
Great explanation... Very easy to understand...
Thanks for sharing. Very well explain
And please continue in making videos like this. Thank you for a great presentation. I really loved it!!!
Good work can u provide same to other protections
We're in the middle of a book right now. Hopefully we'll get back to some videos this year.
Thanks for the efforts
looking forward for more lectures on other protection schemes too
Excellent video and very useful to me..
Great explanation.
Thanks
Thank you very much for the presentation! I would like to know how to calculate the magnitude of the worse case when the fault falls on zone 3 of relay.
thank you!
You'd have to model the system and decide how far, and in what direction, you want zone 3 to protect.
Thanks for making it so simple
Thanks for uploading this video. Nice and clear, great job.
Sir, you are amazing.
How to understand forward and reverse direction for zone settings? Like in case of Relay2 we have set zone 1,2 from right to left but similarly for Relay1 its zone1,2 is from left to right!
Forward is towards the protected device (the line in this case), reverse is current flowing away from the protected device.
Thanks.
Great presentation
Excellent presentation
A very clear and informative video, thanks!
+Phil Moseley Thanks
VERY NICE AND CLEAR EXPLANATIONS
pls update more training videos
Epic video, really intuitive! keep the excellent work!
superb understanding video
Good animation
Thanks for the video. This was very useful information.
Thanks. Glad you liked it
Excellent presentation. I have a question. Line distance protection advantage is its independence on change of the system beyond of the zone of protection (because is based on impedance) but is always described in scenarios where power flows in both directions, there are various zones of protection and a pair of relay are used, one at each extreme of the line. But in cases where there are just one zone of protection and unidirectional energy flow (for example in my case, a 40 KM 115kV single line feeding a radial/terminal substation), does it make sense to use line distance protection just at power source side?.
+janavax
Sure. Many generator protections schemes apply distance protection looking out toward the system with significant time delays as backup protection to isolate the generator from faults external faults not cleared by external devices. Impedance protection would be applied anywhere that you want to create a specific zone of protection and can predict the impedance of that zone.
pls make video with 78 function for generator protection
I'll put it on the list. In the meantime, I have a whole chapter dedicated to 78-Protection and testing in The Relay Testing Handbook: Generator Relay Protection Testing
Good job fantastic video
every good, thanks you must great man. perfect voice！
Very much helpful . thank you. Keep doing
Hi I was wondering, what criteria would determine a communication based schedule like pott, or Ducb etc.
I know line differential is used when line SIR is very high and distance based protection cannot be applied.
You also mentioned that grid can't handle large duration of fault contribution.
Can you please give a real world situation,
Parminder Dhawan
Some choices are based on Technology such as line differential (need fiber), DCB or DCUB (need carrier equipment). PUTT schemes shouldn't be used in systems with weak infeeds.
I was more talking about equipment rather than the grid. All equipment on the grid can withstand some fault current for a short duration. The longer the duration, the more the insulation breaks down or arcs form.
Amazinggggggggggggggggg! it's very helpfull for electrical engineering
great work!
is this mho relay or impedance relay that is being used?
An MHO relay is an impedance relay with a circle characteristic
Is this the same as three stepped distance protection?
Yes
Very Informative. Thanx :)
Thank you for this presentation!
I'd like to know whether there are softwares that allow to test and simulate distance peotection.
Thanks again
Thanks for the comment. You can try these animations relaytraining.com/tag/line-distance-protection-21/
Valence Electrical Training Services
Not that I know of other than the ones in the comments.
Very clean explanation. Like and subscription :)
Thank you .. simple and straightforward :) =D
+mohamed yassin Thanks!
Thank you ever so much !
Nowadays distance relays modeld like D60 P742, REL670 are coming with 5 zones. what's the advantage of increasing this zones. Line differential are used only if the lines are less than 10km . How to communicate with remote end relay
The only advantage is increased flexibility for users who want to fine-tune their zone protection. I can't believe the maximum distance for a fiber optic connection between two line distance relays is 10km. Can you send the source information with this limit?
Can you please explain the difference among POTT, PUTT, DCB schemes
You can follow this playlist th-cam.com/video/s_IrsNHv4aQ/w-d-xo.html, or buy The Relay Testing Handbook: End-to-End Testing relaytraining.com/relay-testing-handbook-series-v3/
Thank you very much
Communication assisted Protection Schemes could be good because the fault should be cleared in minimum time in order to save all the protection equipment and self isolate the Transmission line
Excelent video thanks for sharing it!!!
Sir can yu explain about zone protection
That's what this video is about
hi your videos are very helpful..am working in electrical protection designing..plz give me a video link that you mentioned as1st video of distance protection
got it...
can you send to me also
put the link here please
hi all are nice works thank u !
Nice chanel, and grate vídeo
Nice bro
MRS WATTON WHATS GOOD!
thank you sir, can you share the software used to make this animation please?
They were created in flash and you can play with in the link in the description.
Thank you for the tutorial... :-)
+Tanvir Ahmed Thanks!
TS?
hi... can u p[lz share video on relay settings calculations & distance relay testing... thanks in advance
+Shahzad Hashmi Thanks for your comment. I've put your request on the list, but it is pretty far down at this point. We plan to put out more videos in 2016.
so good ..
Thanks so much -Now am researching for distance relay scheme plz I need support
GOOD
Please ziv
waseva
Hindi me bnaye sir