Nice video if the questions can be explained. A number of people (including myself) asked why the factor of 1.05 comes into the equation. I still prefer the per unit method. It eliminates the need to determine what voltages should be used at different levels if you have multiple transformers. Also, all those motor loads will definitely contribute to increasing the Isc at point 3. Suggestion is that if you don’t want to bring motor contribution into example, don’t specify motor loads. It can confuse some readers thinking that you don’t need to add motor contribution.
@ratssaesquareallaboutelect5919
3 жыл бұрын
Thank you for sharing your views and thank you for the question, Answer to 1.05 question is : 1.05 is a voltage factor required in the calculation to account for Voltage variations in the system,if we consider voltage variation of +-6% in voltage , we have to use factor of 1.05 in the formula as per standard IEC 60909.
@pietervdberg7055
3 жыл бұрын
@@ratssaesquareallaboutelect5919 Thank you for your reply. Much appreciated.
@richhall3662
3 жыл бұрын
@@pietervdberg7055 Also note that motor contribution only occurs for 3 to 4 cycles for asynchronous or 6 cycles for synchronous machines, so not a huge factor when sizing equipment based on steady state conditions or fault levels that can exist for hundreds of milliseconds or more. Also the 1.05 takes into account the voltage factor or voltage rise that occurs on phase due to the raised neutral potential and normally relevant on single phase shorts
@sumitmondal548
2 жыл бұрын
@@richhall3662 nice
@charzanboo9940
3 жыл бұрын
I was asked to perform the above short circuit calculation in an interview...in my head.
@musabkanani2873
4 жыл бұрын
Iam senior electrical engineer Your explain is soo good so thanks
@walterlopez5465
4 жыл бұрын
Excuse me Sir, can you tell which standard support this calculation, i'd really appreciate your answer. Greetings!
@hijazahmad1736
4 жыл бұрын
Nice... I was searching for this type of explanation.. Excellent
@justinlow-thion77
Жыл бұрын
very good video tutorail. simple explanation and easy to understsnd
@ratssaesquareallaboutelect5919
Жыл бұрын
Glad it was helpful!
@muhammadabduljaleel1811
4 жыл бұрын
Very nice with good explanation
@joegellido2596
5 жыл бұрын
The presentation will be complete if motor contribution to fault is considered which is very important factor..
@mohammedsaifullah6437
4 жыл бұрын
Motor and Generator as well
@ImranKhan-nu6xw
2 жыл бұрын
Thanks nice vedio about short circuit study
@mthuthuzelimatsheke5422
Жыл бұрын
It's so meaningful and professional classes i would like to join as a mamber please admin
@vikasgupta-hl9sq
3 жыл бұрын
Explained very nice
@ricrobertogonzales8341
3 жыл бұрын
what is the effect of the motors in the short circuit calculation?
@niluv3982
Жыл бұрын
nice
@ratssaesquareallaboutelect5919
Жыл бұрын
Thanks
@umaid-nungshatpa
2 ай бұрын
Hi Informative New Subscriber
@ktsmurthy21
5 жыл бұрын
If Generator(1.5 MVA) is running , Then How to Calculate Fault current.
@liewts1049
4 жыл бұрын
Could you also comment on the assumption made on the impedance of the power supply utility? Thank you.
@noname-ug2qx
2 жыл бұрын
Why is the backup generator not included when calculating If at point 2 (Busbar)?
@sunilkumarmoharana7639
5 жыл бұрын
Please explain the factor 1.05. how it comes.
@mazmaz1981
4 жыл бұрын
sunil kumar moharana 5% voltage tolerance, which is very typical.
@ratssaesquareallaboutelect5919
3 жыл бұрын
thank you for the question, Answer to 1.05 question is : 1.05 is a voltage factor required in the calculation to account for Voltage variations in the system,if we consider voltage variation of +-6% in voltage , we have to use factor of 1.05 in the formula as per standard IEC 60909.
@user-yd1mr6ir9d
10 ай бұрын
one of the best
@mourshadhaider7361
4 жыл бұрын
Could you please explain number "10" in the formula for z(transformer). Where did it come from.
@itanongmokayengineer
3 жыл бұрын
its contant in order not to include the thousand in the kva of transformer instead using 2000000 you will use 2000
@surendrakverma555
3 жыл бұрын
Good
@user-gk7pn2zh3x
7 ай бұрын
Very good . .
@RaviShankar-sj7qs
6 жыл бұрын
Very Informative video admin. Please upload video of disadvantages of harmonics and ways to arrest them.
@ratssaesquareallaboutelect5919
6 жыл бұрын
Thanks for the feedback , will try to make the required video
@subhendumukhopadhyay3535
11 ай бұрын
Nice one
@tapasbarua4301
3 жыл бұрын
Very nice video. But I did not see any contribution of motors into the fault point as a secondary source and alternator and also why you have included 1.05XV in the calculation?
@shuvanilmukherjee1595
2 жыл бұрын
HOPE YOU HAVE NOT RECEIVED ANY ANSWER.
@atoz5950
3 жыл бұрын
Many thanks for you .. please and kindly, Re-calculate the Isc for generators
@mazmaz1981
4 жыл бұрын
What about motors contribution to the fault?
@Keepit-nq3id
4 жыл бұрын
Good question the reverse currents shall be calculated
@jkj1459
4 жыл бұрын
BEAUTIFUL
@loubensoctave3986
6 жыл бұрын
Nice video. How can I contact you? I have many questions to ask.
@joelcastillo3902
3 жыл бұрын
No way, she's Siri the robot!
@coopers0218
4 жыл бұрын
Pls help with data sheet reference for Cable impedance value. It seems you have considered Cable resistance value instead of Impedance. Pls clarify. Thanks
@Nour-ds3ib
3 жыл бұрын
If you multiply kva by 1000 and kv by 1000 but undersquare and make per unit impedance 0.06 It makes the same number
@devendrasharma2418
3 жыл бұрын
You are right, I think data of DC resistance value has been considered here, instead of which cable impedance as per manufacturer's data should have been considered.
@velusamypothiraj2300
4 жыл бұрын
Where it's coming 10, in impedance of transformer, what is the fault current in 11kv side
@ratssaesquareallaboutelect5919
4 жыл бұрын
it can be obtained from transformer rating plate.
@amarsrivastav1167
4 жыл бұрын
@@ratssaesquareallaboutelect5919 sir pls explain from where it's coming 10
@sohrabalmajose4082
17 күн бұрын
what happen to the current contribution of the motor ? you have not consiger it in your calculation. for your info tnx
@bradencutajar3301
4 жыл бұрын
At 1:43, there is no reason to multiply by 10
@shuvanilmukherjee1595
2 жыл бұрын
I THINK SHE DONT KNOW
@abcdchanchan1
Жыл бұрын
Maybe No need to multiply by 10, she can’t explain
@JDABD
2 ай бұрын
Why it is multiplied by 10?
@patelkaushik2996
3 жыл бұрын
Medam send video for HT 11KV TO LT 415 V relay coordination method
@e-powersolution7225
Жыл бұрын
1:41 thanks for your video, why while calculating z transformer multiple with 10
@satishkumar-wm9yl
2 жыл бұрын
please can you share and update more videos of typical calcualtions of short ckt Transformers and RMU Swithchgears, thanks
@jkmultimediasolutions3935
2 жыл бұрын
Thanks for the video. Please when you mentioned number of runs; did you mean the number of cables or what ? Please, explain it further. Thanks.
@ratssaesquareallaboutelect5919
2 жыл бұрын
No of run means no of parallel cables
@amritthakur9712
Жыл бұрын
Nice
@prakashksp2918
Жыл бұрын
Please upload videos on instantaneous current formula
@jcazur70
Жыл бұрын
Why did you not consider the contribution of the motors below and the generator above whose ratings are significant????
@MEOVLOGz
2 ай бұрын
what method is this?
@trimafs
3 жыл бұрын
Hi, Thanks for informative video can you please also give the reference for formulas
@soumya2221
2 жыл бұрын
What is the fault current contribution from motor
@mudasirhashmi8907
3 жыл бұрын
How do you the cable impedance as .0077 and what are the formula you are using
@zainliaquat9537
2 жыл бұрын
Can you please explain why you are dividing the line voltage by the square root of 3 in Isc formula (At Point 1) ? Your response will be very helpful.
@jay403
Жыл бұрын
it is incorrect. There is no point dividing by root3. Any current is simply V/Z. 1.05 is form factor.
@kachhuap3ycentre505
3 жыл бұрын
Beautiful video . Thank you so much sir.
@sakirdag2976
4 жыл бұрын
thx
@sungmopark0405
5 жыл бұрын
Could you explain why symmetrical fault L-L-L-G and L-L-L is same?
@ratssaesquareallaboutelect5919
5 жыл бұрын
The behaviour of LLLG fault and LLL fault is identical due to the balanced nature of the fault Three phases are equally affected in these type of faults and the system remains balanced. Hope your query is resolved and pl keep watching the channel for more useful videos. thanks.....
@manojshukla3598
5 жыл бұрын
how 1.5 comes in this equation
@mdshamsealam4024
3 жыл бұрын
How number of runs between point 1 and 2 are 7 ?
@mdtarique6305
2 жыл бұрын
Provided in Ts
@mohammedsaifullah6437
4 жыл бұрын
But what about generator current
@niksontalan5803
4 жыл бұрын
How to calculate MVAsc on transformator and feeder
@jinishcrajan
5 жыл бұрын
can explain how 1.05 has been considered
@ratssaesquareallaboutelect5919
3 жыл бұрын
thank you for the question, Answer to 1.05 question is : 1.05 is a voltage factor required in the calculation to account for Voltage variations in the system,if we consider voltage variation of +-6% in voltage , we have to use factor of 1.05 in the formula as per standard IEC 60909.
@TheSuperAboody
4 жыл бұрын
What do you mean by Number of Runs?
@Keepit-nq3id
4 жыл бұрын
For example 3 cable runs means 3 number of cables
@TheSuperAboody
4 жыл бұрын
Thank you
@poojap2508
4 жыл бұрын
Hw did u get 1.05 while calculating Isc
@ratssaesquareallaboutelect5919
3 жыл бұрын
thank you for the question, Answer to 1.05 question is : 1.05 is a voltage factor required in the calculation to account for Voltage variations in the system,if we consider voltage variation of +-6% in voltage , we have to use factor of 1.05 in the formula as per standard IEC 60909.
@ranjan1436
5 жыл бұрын
please explain, how? to size the KVA of a transformer.
@rkthemgil
3 жыл бұрын
What is 1-05 in the formula?
@ratssaesquareallaboutelect5919
3 жыл бұрын
thank you for the question, Answer to 1.05 question is : 1.05 is a voltage factor required in the calculation to account for Voltage variations in the system,if we consider voltage variation of +-6% in voltage , we have to use factor of 1.05 in the formula as per standard IEC 60909.
@rolandomullasgo48
2 жыл бұрын
Where did you get 1.05 shown in your cakculation.
@ratssaesquareallaboutelect5919
2 жыл бұрын
As per standard IEC 60909 - 2001 , We have to consider the voltage factor of 1.05 in LV fault calculation (100V to 1000V).
@lanzsolissiargao8477
4 жыл бұрын
What do you mean of number of runs?
@ratssaesquareallaboutelect5919
4 жыл бұрын
no of parallel paths are termed as no of run.
@kritabarma
2 жыл бұрын
What about motor contributions??
@atmsc4nd4l
3 жыл бұрын
and why is that motor contribution is neglected?
@thajmulhussain4144
4 жыл бұрын
HOW YOU DETERMINED OHMS(0.0778) AT BETWEEN POINT 1 TO2)AT3.41?
@wescointernationalgroup6494
4 жыл бұрын
U have to take transformer impedance x10xline volt x line volt
@emekaesenwa387
5 жыл бұрын
The contribution of the electrical motors to the fault current wasn't captured. It will supply fault current to the bus which it is connected to during a fault
@emilsify
4 жыл бұрын
you are correct during the fault there are some contribution from the motor this method seems shortcut.
@atmsc4nd4l
3 жыл бұрын
why do you have 1.05? does that mean you have increased the voltage to 5%?
@anilkumarmehta1923
Жыл бұрын
But you have not considered the incoming grid and generator connected which these will contribute
@Nour-ds3ib
3 жыл бұрын
Any one please can tell me what's meant by number of Runs????
@ratssaesquareallaboutelect5919
3 жыл бұрын
Number of runs mean number of parallel paths.
@shelfrobthomas449
5 жыл бұрын
is 1.05 in the equation a constant value and how about the impedance value of cable ohms per km is it also constant?
@ratssaesquareallaboutelect5919
5 жыл бұрын
1.05 is part of equation and impedance of cable can be obtained from the cable manufacturer . Thanks for writing
@rasengan9743
2 жыл бұрын
1.05 is a voltage correction factor Voltage maximum/voltage minimum 440÷410
@iswarmahanta6905
5 жыл бұрын
What is the value of 1.05
@wirotebua6971
5 жыл бұрын
As I guess, the prefault voltage is 105% of norminal voltage thus the factor 1.05 is used?
@ratssaesquareallaboutelect5919
3 жыл бұрын
thank you for the question, Answer to 1.05 question is : 1.05 is a voltage factor required in the calculation to account for Voltage variations in the system,if we consider voltage variation of +-6% in voltage , we have to use factor of 1.05 in the formula as per standard IEC 60909.
@crisrobersonsantos9192
5 жыл бұрын
Is the short circuit at fault 3 = 32.58 KA?
@ratssaesquareallaboutelect5919
5 жыл бұрын
thanks for writing to the channel , I Sc at point number 3 is : 33.5KA Pl keep on watching the Channel for other useful videos.
@liewts1049
4 жыл бұрын
Thank you for the nice video, this considered single phase to ground fault. Would you also make a fault current calculation video for ph-ph, ph-ph-gnd, 3ph fault?
@fereshteh5205
2 жыл бұрын
@@yaminoshinn1473 415 v is line voltage, by dividing on sqr3, it would be phase voltage
@madhusudan6395
Жыл бұрын
What is 1.05? Pl.describe
@keshabchandratripathy7300
3 жыл бұрын
Please find explain the formula used
@malam4883
5 жыл бұрын
What should be breaking capacity of cb at point 3.
@kilumumahesh935
3 жыл бұрын
Mr M.salam The breaking capacity of the breaker purely depends on load nature. Ex: if your load 80% const power & 20% const impedance. Then the SC contribution will be some value.. Or If you load purely 100% constant power load, then the SC Current from the load will be some other value.. So as per above examples the SC Current contribution from the load side may very as per the load type.. Therefore = SC Current contribution from upstream + SC Current contribution from load end side = breaking capacity of the breaker nothing but (Ics or Icu)..
@kilumumahesh935
3 жыл бұрын
To each and everyone .. First go through the video carefully .. Why everyone asking regarding what about load SC Current contribution..?? Channel was created fault at the Trafo LV bus. From the upstream we can find Trafo SC current contribution and from Downstream the load SC current contribution. The upstream and downstream SC currents will get added up and visible to us at Bus right side.. So channel was trying to stress the point is how to calculate the fault current contribution from the upstreams not from the load end side or downstream side.. The channel was not stressing any point like.. this is the RMS SC current so based upon the this SC current only you have to choose breaker Ics or Icu.. Hope everyone understood.. Thank you...
@DJLMGT
3 жыл бұрын
what means 7 runs?
@ratssaesquareallaboutelect5919
3 жыл бұрын
7 runs means 7 numbers of parallel connection
@haithamahmed8747
4 жыл бұрын
good video but where is the motors contribution, they will raise the fault level !!!
@vijaymaurya9070
5 жыл бұрын
Z of cable where this value ,how to find catalogue or other method pl explain
@ratssaesquareallaboutelect5919
5 жыл бұрын
Z of cable can be obtained from the manufacturer. Thanks for writing.
@pranayprakash3877
4 жыл бұрын
No of run is 7 you said, where this come from
@ratssaesquareallaboutelect5919
4 жыл бұрын
for example, 7 parallel paths are assumed here.
@vinnnyvinvin
3 жыл бұрын
@@ratssaesquareallaboutelect5919 Hi, does this mean parallel paths for 3 cores (3 phases) and 1 core for neutral? any earth connection?
@dilermehndishirazee8077
5 жыл бұрын
Four 20KVA generators are connected to 11 kV bus what is the Fault MVA at bus?
@aspiringenggs1
5 жыл бұрын
Question is incomplete...Actual Impedance of generator is required for Fault MVA
@senthivelgopal567
6 ай бұрын
why here u r multiplying Z% by 10 , could please explain, if anyone else also most welcome
@shuvanilmukherjee1595
2 жыл бұрын
MAM WHY CALCULATING Z YOU ARE USING MULTIPLY BY 10
@patelkaushik2996
3 жыл бұрын
Medam send video for HT 11KV TO LT 415 V relay
@quirinoguillepajr3979
5 жыл бұрын
Not comprehensive it does not consider the available fault MVA at the utility and motors subtransient reactance
@ratssaesquareallaboutelect5919
5 жыл бұрын
This type of calculation is used for deciding the Short circuit Breaking Capacity of MCCB to be used. Other factor as mentioned can be also calculated. Thanks for writing
@shamirdebnath7407
4 жыл бұрын
@@ratssaesquareallaboutelect5919 Could you please explain how to select the required breaking capacity of individual motors?
@lov7587
4 жыл бұрын
Hi Sir, How did you get the figure of 1.05 in the formula? Please advice.....
@ratssaesquareallaboutelect5919
3 жыл бұрын
thank you for the question, Answer to 1.05 question is : 1.05 is a voltage factor required in the calculation to account for Voltage variations in the system,if we consider voltage variation of +-6% in voltage , we have to use factor of 1.05 in the formula as per standard IEC 60909.
@user-gk7pn2zh3x
7 ай бұрын
IF the Voltagebminus side ,variation is 10% on plus sideand,what. is the factor.
@anugarg4864
5 жыл бұрын
Dear Mam, Please tell me about the number of run ,What is this ?
@ratssaesquareallaboutelect5919
5 жыл бұрын
Number of run means , number of parallel cables, Thanks for watching.
@Maharana_Rahul
3 жыл бұрын
Ex:- each phase four runs
@anwarhussainansari13
3 жыл бұрын
Transformer impedance already given %6=.06 ohm so why u are re calculate ?
@staceyksmith1095
3 жыл бұрын
The transformer impedance given in percentage is used when you convert all impedances to Per Unit. She avoided the per unit conversions by calculating the Z impedance first
@AbdulRahman-pm1nd
2 жыл бұрын
What is value of 1.05
@ratssaesquareallaboutelect5919
2 жыл бұрын
As per standard IEC 60909 - 2001 , We have to consider the voltage factor of 1.05 in LV fault calculation (100V to 1000V).
@deepakgrg1408
4 жыл бұрын
ok
@patricksalvacion8975
5 жыл бұрын
How to obtain the number of runs?
@Feitan0123
4 жыл бұрын
it is the number of wire per phase.
@dsmahatpure8199
4 жыл бұрын
Mam in farmula 1.05 and 10 is coming from where?
@ratssaesquareallaboutelect5919
3 жыл бұрын
thank you for the question, Answer to 1.05 question is : 1.05 is a voltage factor required in the calculation to account for Voltage variations in the system,if we consider voltage variation of +-6% in voltage , we have to use factor of 1.05 in the formula as per standard IEC 60909.
@patelkaushik2996
3 жыл бұрын
Nice pic medam
@IbrahimMA-EGY-suez
2 жыл бұрын
but you ignore motor reactance how could you !!!
@keshabchandratripathy7300
3 жыл бұрын
I feel for Z Tago in formula given instead of 10 we will write 1000.please clarify
@muhammadbinali6223
Жыл бұрын
too complicated , instead do this, first calculate the sec current of transformer, which is Isec= rated KVA/sec voltage, incase its 3 phase (1.73 into voltage) , u will get Isec of transformer, now next step to calculate short circuit current by using the formulae , isc= Isec*100/%imp of transfomer , which will give u the short circuit curent on busbar by transformer
@nagendranm7322
Жыл бұрын
How to calculate point no 2?
@kachhuap3ycentre505
3 жыл бұрын
Charnam sarnam gachammi Paramji papar paramyog p3y hamare sanatan dharm ki Ati prachin Vidya hai ye Vidya param Pawan Paramji ki hai janane ke liye reply Kare charnam sarnam gachammi.
@lemmirorissa5217
2 жыл бұрын
Could you please explain number "10" in the formula for z(transformer). Where did it come from.
@AzkadanAhmad
2 жыл бұрын
Same Question
@user-hy6ju4gz6c
5 жыл бұрын
how do motors affect short-circuit currents?
@berniesayson6612
4 жыл бұрын
for solving of short circuit current of electrical system all connected equipment's and load must be consider, in your calculation load is not considered.
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