题目内容
用104 V高压输送200 kW的电功率,在输电线损失2%的电功率,则输电线的电阻为_____________Ω;若把输送电压降低为2 000 V,则输电线上损失的功率将占输送功率的_________________%.
10 50
用104 V输电时的输送电流:I1=
A="20" A
由PR=P×2%=I12R得:R=
Ω="10" Ω
若用2 000 V输电,输送电流:I2=
A="100" A
输电线损耗的功率:PR′=I22R=1002×10 W=105 W,
则:η=
=50%.
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824120729963909.png)
由PR=P×2%=I12R得:R=
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241207300101155.png)
若用2 000 V输电,输送电流:I2=
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824120730057925.png)
输电线损耗的功率:PR′=I22R=1002×10 W=105 W,
则:η=
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824120730104912.png)
![](http://thumb2018.1010pic.com/images/loading.gif)
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