Tan Delta Testing (DF or PF) Explained - Part 3 - UST and GST modes

[@jonsolkar]

nice explanation sir...👍👌👏👏

[@sheppo17]

Thank you very much !

[@tituspupe9128]

Thanks well elaborated

[@shehab1798]

Thank you Andrej! I have watched all three parts and I must say, you have made it very easy and understandable! Great job, man!

[@sheppo17]

Dear Shehab ! Thank you so much for your comment ! It means a lot :)

[@shehab1798]

@@sheppo17 My pleasure

[@dezch9752]

Thank you Sir

[@sheppo17]

Most welcome

[@wesleyeat-xrte7673]

Thank you Andrej for all complets contends!!!

[@sheppo17]

My pleasure!

[@user-oo8zt1sc1c]

Incredible awesome explanation of this subject. I really appreciate the tima, you Sir took to do these great videos. Thank you so much!

[@sheppo17]

Thank you, your comment means a lot to me Sir

[@hitmancaptaincool4073]

Excellent.. Loved the way the topic is taught. Thank you sir

[@sheppo17]

And thank you for the comment Capt. Cool :)

[@bayuoktavia6342]

very good video,i follow it since the first series. thnks alot.

[@sheppo17]

Thank you Bayu :)

[@ashikrahman1094]

These are very informative video. Thank you. I used an instrument Model CB-100D to test a 500kVA dry type transformer but I am not a getting the null point (unstable pointer) on the equipment when switching the knob from Capacitance to DF. Could you please explain me why? Megger of the transformer is in Giga ohm range.

[@guven6759]

wonderful lesson , thanks

[@sheppo17]

Thank you very much Güven

[@mutumbaful]

Andre I was carrying out the test on new bushings using UST but getting 0.001% for all bushings different from factory tests. Am using RD 8000 testing kit. Please advice me what could be the problem

[@sheppo17]

Hi Moses ! First of all excuses on late reply. Please clarify one thing - were the results different from nominal results by 0.001 % OR were the results itself 0.001 % ? Because UST is a correct mode to measure C1 on bushing.

[@darpanjpatel]

Thanks sir, now I have clear understanding between GST, GSTg & UST... Request to please upload more testing video like this...

[@sheppo17]

darpanjpatel I am just uploading one long video that explains most of this in one sitting. It is a recording of a webinar

[@vinodmusicprogamer9503]

Superbly explained watched all 3 parts 👍👍👍

[@sheppo17]

Glad to hear that, this is one of few constructive comments I got. Thank you Vinod

[@maythemnadhim4730]

Very good explanation. many thanks

[@sheppo17]

Glad it was helpful Maythem !

[@bxsd007]

Very useful video Sir 👌👍 Make more videos on system protection relay testing and interlocking system in different substation... like REF, Differential and generator protection...

[@ajaykarne5648]

Sir, very good video gets cleared all doubt of tan Delta tesing. Request u to please make another video of tan Delta tesing of HT motor

[@sheppo17]

Hi Ajay ! Will try to do that

[@shafqatkhan5571]

Very good information video. Thanks Sir

[@sheppo17]

You are most welcome Shafkat

[@tituspupe9128]

Andrej is there a serious change in results, when testing overall tan delta omitting a stabilizing winding? E.g instead of choosing three winding but choose two winding on test.

[@sheppo17]

Well I have not tried it, but I do not think there should be any difference if you correctly set up the measurements

[@tamjidkabir1543]

Excellent content! Thanks Andrej :)

[@sheppo17]

Dear Kabir ! And thank you for the comment !

[@rapanchal29]

Nice analysis thanks

[@sheppo17]

Thank you !

[@transientmatter6088]

Brilliant 👏 webinar

[@sheppo17]

Thank you transient matter:)

[@harshanasenevirathna6677]

helped a lot,Thank you!

[@sheppo17]

And thank you for watching Harshana !

[@simmonsalex755]

Great videos series! Thanks! By the way i wonder what instrument you used for this test.

[@sheppo17]

Hi Alex, I used TDX 5000 and STS 5000 + TD 5000. You can find them on www.altanova-group.com site. Let me know if you need some guidance around that.

[@رضاالطرشاني]

Can you explain how to test tan delta for generator winding.and what should be the satisfactory value of the resultant measurement..thanks alot fot those great videos

[@sheppo17]

Hi ! My pleasure. For Rotary Machine testing you are testing mostly only the stator insulation (stator winding towards ground). So what you do - you generate high voltage between stator winding and a ground. For Rotary machines you often do a step up test and a step down test - so you generate (for example) 0.4 Uo, 0.5 Uo, 0.6 Uo, 0.7 Uo, 0.8 Uo etc.. and then downwards. Normal values should be between 3% and 5%, depending on insulation material. We might do a video on Tan Delta testing on Rotary Machines soon.

[@raminmollahajloo4059]

Excellent thank you 👏👏👏👏👏👏👏👏👏💐

[@sheppo17]

Thank you !!!

[@themaccabee1890]

Great Video Sir 👏👏👏

[@sheppo17]

Thank you Neo ! It is for people like you I make this :)

[@baburamakrishnan9690]

Very good explanation,

[@sheppo17]

Glad you liked it

[@sayedtaha5196]

Excellent explaining

[@sayedtaha5196]

Excellent explaining

[@ashtv9439]

Respected sir, iam an electrical engineer and iam working in switchyard substation.my humble request to upload more videos of testing switchyard equipments like Power transformer,Reactor, CVT,CT,CB,LA etc.

[@sheppo17]

ASH TV we plan to do this in the future.

[@krishnamacharikkumbhar6212]

For 3 winding transformer can we please provide combination so that all specimen can be measure in one go..

[@sheppo17]

Hi ! You cannot measure all the speciments in one go. Even if you have only prim and sec you will need to change genaration and measurements once, and you need to change also when you do trafo with prim, sec and tert. You wouls first generate in the HV (Primary) side and measure from Secondary and Tertiary to determine CH, CHL and CHT. Then you move to generate from Secondary and measure from Prim and Tert to determine CL, CHL(again if wanted) and CLT, and last is generation on CT and measurement from Prim and Sec to determine CT, CHT(again) and CHL (again).

[@jayasenanchinnathambi7038]

nice explanation! thank you

[@sheppo17]

You are most welcome Jayasenan

[@bayuoktavia6342]

sir what is function of aplying different frequency on tan delta test

[@sheppo17]

You would to that when measuring the tan delta of bushings mostly, and when the values are borderline, like, close to 1%. Then if you did frequency sweep, let us say - 15 Hz, 35 Hz, 50 Hz, 75 Hz, 105 Hz, 150 Hz, 205 Hz, 345 Hz, 405 Hz, 455 Hz and 500 Hz, what you would want to see that TD has more or less the same value. BUT if you see in lower frequencies higher (significantly higher) and then drop of values to lower values, that would mean that water had penetrated the bushing.

[@JundenieGonzales]

Hi.. IEEE uses IpF while IEC uses Tan-Delta. How you convert IpF to Tan-Delta in this case.

[@sheppo17]

Can you elaborate what is IpF ?

[@JundenieGonzales]

@@sheppo17 Insulation Power Factor

[@bhaveshmiyani8276]

As per video, GST gA measuring only CH while GST g(A+B) measuring (CH)+(Parellel of CHL and CL).... This is how??

[@taruna2690]

HV lead that is red in colour means injected voltage location changed. Means ones in HV side injected and second time in LV side injected.

[@رضاالطرشاني]

Can this test be done for dry transformers .i.e air dried or only for oil transformers

[@sheppo17]

Hi ! You can do this on any transformer. And not only transformer - but also motor or generator or circuit breaker. Basically you can do this test on any electrical insulation.

[@رضاالطرشاني]

@@sheppo17 for transformers 6/.0.4 kv and 6/20kv what would be the injected voltage is it 20kv and what is the voltages for the pushing?

[@sheppo17]

@@رضاالطرشاني So you never need to go more than 12 kV according to IEC and IEEE. Even the 220 kV and 400 kV transformers use 10 kV or 12 kV as testing voltage. That is because at 12 kV all polarisation in insulation has finished taking place and there is no need to increase the testing voltage. So to accurately answer your question - you would generate 10 kV or 12 kV on the HV side (it should not make difference 10 or 12), and thus test insulation HV to GND and HV to LV and then you would move the generation to the LV side and generate maximum allowed voltage which is 0.4. Also keep in mind that 0.4 is probably Ph to Ph voltage and with test set you always generate Ph to GND so probably 230 V on the secondary side. With that voltage you would verify insulation LV to GND and you could repeat HV to LV insulation to see if you get the same number as when doing the test from the Primary side

[@bahrimouloud6980]

Thanks so much

[@sheppo17]

Thank you for watching

[@taruna2690]

Dear Sir, It is requested to provide video for Physical meaning of Tan Delta Measurement of Winding under different modes UST GST GSTg for a 3 phase 400/220kV/33KV, 315 MVA Autotransformer with 33 kV Tertiary. What does it measure under different modes and significance.

[@rithviksomalraju4532]

can u pls give some examples where u use input B as well

[@sheppo17]

If you have transformer with primary, secondary and also tertiary windings.

[@shafqatkhan5571]

Thanks and what,s mean GAR R in test set c & df

[@sheppo17]

I am not sure what do you refer to when you say GAR R ? Where have you seen it written or mentioned?

[@johnirishlopez4219]

Does the grounding system affects the result of the Tan Delta? Like for example I am testing a new transformer and the substation has a grounding resistance of >1.0 ohm, and i obtained results above 0.5% more likely 0.7-0.8%, is the grounding system a factor or not.. Thank you for your detailed explanation 😊

[@sheppo17]

John Irish Lopez Hi John ! Regarding the grounding what I can surely say is that if it is proper, and I that I mean that there are no discontinuties in the grounding system - the measurment should be correct. If on the other side there are discontinuities in the grounding system, the current running in the ground will not be measured by the test set and you will get wrong measurement value. Of course our experiences are limited and we never added different resistances in the grounding network to observe the Tan Delta result and how is it affected by higher impedance. I can only tell you that you need to have a functional grounding that abides to norms, and if it is so, you should get correct TD results.

[@johnirishlopez4219]

@@sheppo17 thank you for the knowledge sir, i highly appreciated it 😊

[@sheppo17]

John Irish Lopez you are most welcome :)

[@themaccabee1890]

How leakage current is measured?

[@ashtv9439]

sir, do some videos of DCRM testing with connections and tan delta with conncections.

[@sheppo17]

As soon as possible

[@niamatullahasif2531]

Very good explanation. On one made the explanation that much clear than you. Thank you for the video.

[@sheppo17]

Thank you Asif :)

[@AmanSingh-zf1ph]

Hi, Thanks for the information. Could you please explain Tan Delta testing of cables. Also, could you please explain or email some information how to interpret the results based on IEEE400. IT WOULD BE GREAT HELP. I'M HAPPY TO PAY FOR THAT. or Does anyone knows?

[@sheppo17]

Dear Aman, please write to me to [e-mail] and I will see how I can help you

[@sheppo17]

Hi Aman ! We got some experts who know way more than me about this. If you are interested in the courses, please write to me on email mentioned above

[@jayabikash]

Nice

[@sheppo17]

Thank you !

[@electricaltalent7385]

I understand theoritical try to put practical also.

[@sheppo17]

Electrical maintenance and testing - I am doing that, I hope soon that video will be out

[@pulusumunikiran7253]

Thanku sir

[@sheppo17]

You are most welcome !

[@moumitamondal5188]

What is tan delta point actually?

[@sheppo17]

Hi Mondal, Tan Delta is not a point. It is a parameter, a value that describes how good an insulator your electric insulation is. Tan delta as a parameter is tangent of an angle delta, and angle delta i angle between y-axis and total current that runs through tour insulation. Since in an ideal insulation only capacitive current should run, the angle should be 0 and td should be 0. But since there is always some small resistive current running - that angle is always at least a bit different than 0. Just to give you a feeling - if this angle is bigger than 0.7 degrees - we are already in red. Hope this explains the notion.

[@himanshusati3066]

Why GST tan delta value less than GSTg tan delta value. ex- In power transformer GST Tan Delta - 0.483%( CH + CHL) GSTg Tan Delta- 0.563%( CH) It is happening all the time Why ???