Street light power consumption question.
Street light power consumption question.
(OP)
Hi guys,
Case: just an ordinary street light, 400w HPS bulb.
What will be total consumption?
Is this right true?
Lamp 400w
Electrical disribution(rectifier) 100w
Comprehensive Cable Loss 6%, 400x6%= 24w
Transformer loss 3%, 400x3%=12w
Reactive Power Compensation, power factor 0.85
Total: (400+100+24+12)/0.85 = 630W
Please point out where do you disagree, any comments welcome.
Case: just an ordinary street light, 400w HPS bulb.
What will be total consumption?
Is this right true?
Lamp 400w
Electrical disribution(rectifier) 100w
Comprehensive Cable Loss 6%, 400x6%= 24w
Transformer loss 3%, 400x3%=12w
Reactive Power Compensation, power factor 0.85
Total: (400+100+24+12)/0.85 = 630W
Please point out where do you disagree, any comments welcome.






RE: Street light power consumption question.
RE: Street light power consumption question.
The power factor relates to the phase angle between the current and voltage, so you do not divide all the power losses by the power factor. The power factor will cause somewhat higher current that results in some additional resistance losses in the wiring to the light. But nothing close to what your calculation implies. Lower power factor means higher kVA, not higher kW.
I'm not sure what recifier losses are, unless you are referring to the ballast at the lamp. Cable losses look on the high side.
RE: Street light power consumption question.
Can you please write all the calculations, what and how much will be consumed. This calculation was done by company who is offering some products to me, I just want to check if they are telling truth.
Thanks,
Rob
RE: Street light power consumption question.
If someone gave you that equation, they definitely have no idea what they are talking about, or are deliberately misleading you.
RE: Street light power consumption question.
I may have missed a point, but is there a rectifier in the distribution? Where? And how in the world can it have a 100 W power loss? If that is the case, it must be a common rectifier for several lamps. You shall not add that loss to each and every lamp.
Just ignore this guy. And, above all, do not divide with PF to get total power!
Gunnar Englund
www.gke.org
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100 % recycled posting: Electrons, ideas, finger-tips have been used over and over again...
RE: Street light power consumption question.
RE: Street light power consumption question.
Gunnar Englund
www.gke.org
--------------------------------------
100 % recycled posting: Electrons, ideas, finger-tips have been used over and over again...
RE: Street light power consumption question.
Don Phillips
http://worthingtonengineering.com
RE: Street light power consumption question.
I think that is what I said already. There are losses in the ballasts, so the power draw will be somewhat greater than 400W.
RE: Street light power consumption question.
Don Phillips
http://worthingtonengineering.com