A power company generates 100kW to supply an industrial load of 94kW. The transmission line has a resistance of 0.09 ohms. If the power factor is
0.83 lagging, what is Vl?
Simple maths challenge for Electricians
Dec 20, 2015
28 Replies
0.83 lagging, what is Vl?
113.327 kVA at the load? A bit more at the generator.
Do I get my £5 ?
rusty
6
In article , Cursitor Doom writes
6
A crude editor on *nix systems...
That's vi and it's far from crude.
Power Factor is true power / apparent power (Lagging or leading shouldn't matter)
I = 100kw / (0.83 x Vs) = 94kW / (0.83 x Vl)
Vl = Vs - I * 0.09
Vs = Vl x 100kW/94kW
Vl = Vl x 100kW/94kW - 94kW / (0.83 x V1)
0 = Vl x 6/94 - 1/V1 x 113kW0 = V1^2 - 106457
Vl = 326
------------
Double check: I = 347; IR = 31.2V
Vs = 347
I'd love to see why some are saying 6V. I = 18875A; R losses 32MW!!
How can a 100kW generation supply end up losing 32MW?
They may be from Rome.
That was the point I was trying to get across, obviously not very well!
Ah, woss this? polygonum joined the Missing the Point Club? (Prop: m. adams).
You're right....
If you improved it, it would be crude.
No one was...
They were saying 6
Nope.
Nope!
Nope!
I was wondering that, too.
***MILES*** out.
Oh.
OK 6kW loss in 0.09R => I = 258A
94kW => 94/0.83 kVA = 113kVAVl = 113k/258 = 440V
Oh good, I thought I was going seriously wrong, especially as two posters agreed!!
That'll do for me. Congratulations; a 5 shilling postal order is on its way! Incidentally, I broke with precedent and nicked this one off Youtube. The bloke gives the full working of how he got the answer, but IMV it's an awfully bad explanation overall. Still, YMMV. Check it out here:
formatting link
Thanks, don't agree with his interpretation of reactive power, lagging = absorbed etc!
But I have (re)learnt that apparent power is not conserved which is where I originally went wrong, obvious if you think about it, where power factor can be different at the generator and load!
as a line editor, adapted to a screen rather than teletype, it is pretty advanced.
AS a screen based text editor, it is appalling.
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