Voltage drop calculation for Street light
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- Опубликовано: 8 сен 2024
- Through this video you can learn how to do voltage drop calculation for street light. This calculation is very important for Electrical engineer who is working in Road construction or infrastructure field.
but the street light is a single phase load .Why did you consider 3ph power formula for single phase load?
it is 3 phase distributed supply, that is why we calculate overall voltage drop of cable
@@Rashid-iqubalThank you
Useful
Nice video..
Where can i get the costant value for cable(like you took 2.2) as per Indian standard..
Can you upload a video of voltage drop from substation to load ( fan or anything)
{E.g. vd from substation to feeder piller, feeder piller to meterapnel....)
Awaiting for your reply
Thanks Wasim, for constant u can refer to Indian standard or you can check in cable catalogue. Sure i will make video on voltage drop from substation to domestic load.
Thanks!
Welcome 🤗
Nice
In voltage drop percentage you need to divide on operating voltage of lumiaire (220)
We are using here 3phase supply
Cavite
Hello! Sir How does R phase has 9 loads? isn't it supposed to be only 3 loads (R1, R2, R3). why did you consider the load on other phases as load on R phase?
Yes R phase has only 3 nos of load and total circuit has 9 nos. of load.
We are doing 3phase calculation that is why we consider every phase at each point.
@@Rashid-iqubal so if I were to do the same calculation using single-phase formula, I would only consider load on each phase and calculate the voltage drop for each phase. Right sir?
why did you use the 3-phase calculation? isn't this calculation for the branch circuit? As far as I know branch circuit are single phase circuit supplying single phase load (in this Scenario). so, shouldn't the calculation be also done using single phase formula?
does vertical distance ( box to fixtures) also adds to the length of wires for vd computation?
No! that calculation only from Lighting panel to horizontal cable till cutout/MCB. Voltage drop from Vertical cable has negligible.
NIce
Why did you reduce 1 pole in Y1?
Y1 is the beginning of the circuit Y
and also B1 is the beginning of the circuit B
Because we have 3 circuits (3 PH), each circuit has 3 Pole (Luminars)
So Power of R1=Y1=B1= Power of 3 Pole
Power of R2=Y2+B2= Power of 2 Pole
and Power of R3=Y3+B3= Power of 1 Pole
Awaiting your feedback
Thank you
Because i am using 3phase calculation for all poles. If you choose separate calculation like R separate, Y separate and B separate then you need to do calculation in respect of single phase supply. Both way is correct
sir normally when we calculate voltage drop calculation for main panel to distribution box we take total watts and full length of cable and mv value together but sir here you calculate feeder pillar to R1 , Y1 and other value of voltage drop separately calculate sir can you explain the reason for this type of calculation
Sure, very soon i will make video for calculation from transformer LV panel to street light poles.
Hi, If I go for 2 runs how should I consider the Vd constant.
It means If I try with 4Cx16Sqmm - 2 Runs. But as per the vendor details if the constant is 2.546. What will be constant value I should take. Pls advice!!!
in this case you can consider half of constant value. like 2.546/2 = 1.27
thx
Audio Not clear but good video.
What does the safety factor of 10% represent?
Can u do vd calc for branch ckts also
You mean from Substation to extreme end of street light ?
@@Rashid-iqubal no, i mean 3 cables looped to the same street light somewhere in the middle of the main circuit to start another branch circuit. I hope iam making sense.
What is about the main cable size to feeder panel
From substation LV panel to feeder pillar cable size should be 4cx300mmsq, then from main cable we need to make T-joint with 4c×35mmsq and terminate in Service cabinet (Kwh meter) or feeder pillar.
Or its depand on your country standard.
@@Rashid-iqubal thank you for answering
but I have question I am working in street light projects
If I have four circuit cables from the feeder each cable feed 25ples each pole light has power 250w and the distance between each pole 40m
Do think 35mm cable enagh to feed four circuit cables with voltage drop 3%each circuit cable
@@mryounis8291 exactly in that case you need bigger size of cable. Either you can calculate voltage drop or i would prefer it should be 4c×70mm2 cable joint from main cable.
@@mryounis8291 i recommend you pease make voltage drop calculation of branch circuit then choose the cable which provide less then 3% voltage drop. Once you select branch cable then you select next biger size of cable compare to branch circuit. Becase if make T joint from main cable to feeder piller, i am sure length will be short. Then voltage drop will be less as well from main cable to feeder pillar. Hope you got your answer.
@@Rashid-iqubal thank you Eng.Rashed
I am from Oman
near to Qatar
Can you show us by video how calculate the main cable size like this case
Minutes 4:58 , how u get value 1.55? Shouldn’t it be 0.00155? Please reply me 🙏🏻
@3:40 i used power in kilo watt, if u multiply 0.00155 by 1000 you will get 1.55
@@Rashid-iqubal how did u guys even get the 0.00155 pls
@@brendaazia5713 I = P(KW)/646.905 = 0.00155P
I = (P x 1000)w / 646.95 (Power in KW that is why we multiply by 1000 to make in watt only)
I = P1000 / 646.95
I = P1.55
Hope you understand !
If you multiply by 1000, then shouldn’t we take power in watts for calculating I?
This is for 3ph cable what about 1ph
If you use single phase supply, from calculation you can write single phase (220) supply instead of 3phase (415) and remove root 3 while calculating current.
Nice, now what is the solution?
Solution for what ?
@@Rashid-iqubal I meant how to manage the losses of the voltage ? is there a way to bring back the drop?
@@drdayud yes! you can change the size of cable accordingly till the voltage drop match to your requirement. increase the cable size lower the drop
how to select actual cable size for sheet ligth for 2km
For 2 km, it should be larger size of cable required, first choose any size of cable and calculate. If u get voltage drop less then 3% then you can go for it otherwise select next higher size of cable.. try with 25mm2 cable size otherwise check with 35mm2 cable size