Thank you, Mr. Andrej, for the video. I found the explanation very helpful. However, there are still a few things I don't quite understand. 1. In the video, it is explained why the test voltage applied does not exceed 12kV/10kV, as at 12kV, all polarization processes within the transformer insulation are completed. 2. There is also an explanation about changes in geometry in the windings. If the capacitance value drops, it is explained that the transformer winding will undergo mechanical deformation or changes in geometry. My question is, what does it mean when the polarization in the transformer insulation is said to be "completed" at a test voltage of 12kV? And one more thing, what does mechanical deformation or changes in geometry mean?
I would like to inquire about your suggestions regarding the actions we should take for our transformer asset if the tan delta value in the LV-GND (CLG) winding is 1.10%, which exceeds the standard limit. Thanks sir.
Hi Muhammad, you should first take into consideration the voltage level of the PT. If it a EHV or HV, it is more dangerous, and also in that case if, heaven forbid, the PT malfunctions, it will be a bigger issue if it is not operational. But if it is MV and not so important, then potential damage is lower. So first asses how problematic would it be if this PT would not function. Another thing is - what to do next - so I would first see 2 things - what is the old result for that tan delta, and if it changed significantly in a short period of time, then it is a cause for alarm. But if the value was, last time you checked, not so different, if the delta is not big, then it is just a warning. But what I am trying to say is that you guys should probably do more tests. And that means - do DGA (dissolved gas analysis) and see what do the gasses in the trafo tell you about the trafo. You could find out if you have some hotspots by detecting gasses like methane, ethane, ethylene or acetylene. Or if the CO/CO2 ratio is wrong, maybe the paper could be affected, or if the O2/N2 ration is wrong, maybe a bladder or conservator is damaged and air is getting inside. If O2 values are too low, then maybe oxidation in PT is too high and acids might be affecting your transformer. For sure try and find out moisture content in your oil...BTW I am writing all this presuming you have oil filled trafo, which I suppose is true. If not then you have another approach, that also work very much with oil filled transformer, and it is Partial Discharge testing. So I would do more tests, to get a better understanding of the situation. Also feel free to contact me at asepcic@doble.com
Celo detinjstvo, čitave 1980-te godine sam, svako leto, po tri meseca bio tu, u Sabunikama. Nisam bio od 1989. godine i planiram da odem, da se setim lepih dana. Ulica je bila poslednja...iza kuće je bilo samo nisko rastinje i ravno sve do Nina. Ja ne znam naziv ulice, niti mogu po vašim snimcima da odredim...bio sam jako mali...ali, pamtim neke ljude iz Zagreba, Zaprešića, itd... Voleo bih da mogu bilo kakvu informaciju, o ulici, ljudima, ili bilo čemu da nađem... Ovo na snimcima se toliko izgradilo i promenilo.... Bila je mala pošta i jedna mala prodavnica...i lepa staza pokraj koje su bili drvoredi četinara.... Eh, da...
Dragi Vintage Soul, djelim tvoje emocije, pomalo sjetne ali takodjer i sretne vjerujem. Ja sam svako ljeto od kada sam bio beba pa do nekih 20ih bio u Sabunikama. Ljetne ljubavi, prva pijanstva, prijatelji, post i mala prodavnica. Da, puno se promijenilo ali savjetujem ti/vam da odes i vidis, jer iako se puno promijenilo, i dalje ima puno toga sto je tamo bilo i prije i nadam se da ces uzivati.
Hello I have got the report for three phase with big Hfct with MV cable transformer Can explain more for this , in the results i got two different results i want know understand this The red phase said Not identified as PD in the asset 0% ok And the red phase said Not identified as PD in the asset 100% ok What are the differences between them results ??
Buenas tardes. Sres. ALTANOVA. Espero estén bien. Quisiera comentarles que la fórmula para determinar la impedancia de cortocircuito del equivalente trifásico tiene un error de transcripción. El voltaje línea a línea base en kV debe estar al cuadrado. Saludos.
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.
Thank you for your comprehensive presentation I really appreciated so, I have one question please could tell me what is the different between Tan Delta test and partial discharge? With thanks
Tan delta is a measurement that shows you the overall, statistical value of the conductivity of your insulator. While PD is measuring the sparks (microsparks) in the insulation which also gives you an insight in the status of the insulation. Both measurements show the status of the insulation, but each one from its “own perspective”. Like in medicine, for some things CT is better and for some Magnetic Resonance for example. This is answer in short, but many other things can be added
can we do the earth resistance test , without STSG and STLG device ? if yes, then according to the standarts how much the distance should between A and B measure contacts , and spike which is connected to the HV OUTPUT. Thank you
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.
Hello Andrej! Hope you're doing good! I want to know how to get all three phases of a triple pole (3 element) OC CDG electro-mechanical relay trip and flag and get their times, of all three phases/poles, recorded by DRTS64? Using Manual mode, I use all three current channels, phased 120degree apart, and connect them to each phase/element of my CDG relay. Then I use C1-N connection so as to stop the current injection/testing when the relay trips/flags. Problem is that although three discs of the three poles/phases/elements start to move at the same time, they do so at slightly different speeds, varying by 1or 2 seconds. This time difference is enough to causes one disc to trip and flag before the other two, which then causes C1 to stop the current injection/testing and time of only that phase/pole/element is recorded which tripped/flagged first, while time of the remaining two is not recorded. To avoid this we then resort to testing all 3 phases/poles/elements separately, one after the other, which uses up our time. So, is there any way to test all 3 poles/elements simultaneously such that times of all three phases is also recorded? Would appreciate a lot. Thanks Rizwan
Can be used for check the fault (point of connected fault) when the line is off? Or can be used to check if grounding tools already release after maintenance?
We have never tried that function of TFS, so I would say no. In general TFS needs travel waves to function and travel waves cannot be generated unless there is voltage
ok so I c the reflection of the little cubicle as it shoots out so does that cubicle really fly around the city or does it just "make u feel like and c all that thru VR"?
@@sheppo17 oh wow im not familiar with technology like that but how does it stay on that same path and go back into the building when the ride is finished. Is there an invisible wire or something that makes it come back. I thought that part was fake and just a part of the elevator ride and just did VR to make u feel like it shoots out
@@KellyMarie6988 hi Kelly, all is “fake”, all is computer generated and shown on a screen. Like a cartoon just really realistic and shown in the walls of the elevator
@@Azimsaiyed09 well I know some of my colleagues use Matlabband I used it while I was studying, but you see it was a long time ago and I am not anymore using it so I cannot asist you with that since I also am not sure how I would model and simulate a CB
