TRANSMISSION OF POWER BY ALTERNATING CURRENT 391 



1 330 000 

 Current per conductor 7 = pt {) _ n = 82.3 amp. 



Allowable loss per conductor = 1,330 X 0.10 = 133 kw. = 133,000 watts. 



1 S"? 000 

 Resistance per conductor Rf = / 00 ' ^, = 19.64 ohms. 



(O4.0J 



Resistance per mile = 19.64/25 = 0.786 ohm. 



From Appendix H, page 464, the wire having the next lowest resistance 

 per mile is No. 1 A. W. G., the resistance of which is 0.665 ohm per mile. 



Ans. 

 (6) Total resistance per conductor 



R = 25 X 0.665 = 16.6 ohms 

 IR = 82.3 X 16.6= 1,365 volts. Ans. 



(c) From Appendix I, page 465, for No. 1 wire and 48-in. spacing, the re- 

 actance is 0.734 ohm per mile. 

 Total reactance per conductor 



X = 25 X 0.734 = 18.35 ohms. 

 The reactance drop 



IX = 82.3 X 18.35 = 1,510 volts. Ana. 

 (<*) From equation (90), using volts to neutral, (E R = 19,070 volts). 



cos 9 = 0.85 = 31.8 sin 6 = 0.527 

 Eo = V(19,070 X 0.85 + 1,365)' + (19,070 X 0.527 +1,510)' 

 = V(17,580) + (11,560) = V443 X 10" = 21,000 volts. 

 The voltage between conductors at the sending end 



E' G = >/3 X 21,000 = 36,400 volts. Ans. 



21,000 - 19,070 l,9.:n 

 (e) Regulation = 19 Q7() = 19^)76 ol !><>r 



165. Lines Having Considerable Capacitance. Heretofore the 

 line capacitance has been considered negligible in its effect on 

 the regulation. In long lines of high voltage the charging cur- 

 rent, due to the line capacitance, may have a very considerable 





=^~ Ground 

 Fio. 366. Transmission line h:i\ in n-sist.iiire, reactance and capacitance. 



effect on the regulation. It* tendency is to cause tin- voltage 

 to rise from the scmlim: end t< the n-rrivini: end. The capaci- 

 tance of the u-ii;il line is distributed uniformly alnni: the line. 

 The calculations are very considerably simplified, howev' 



