40 TRANSMISSION LINE FORMULAS 



for the following line: 



Length of line ............... .............. 300 miles. 



Spacing ................................... 10 feet. 



Conductor, No. ooo copper cable of 0.330 ohms per mile. 

 Load (at receiver end), 18,000 K.V.A., 104,000 line volts, 



90% P.P., three phase, 60 cycles. 

 [Prob. A, page 2, G. E. Review Supplement, May, 1910.] 



Answers: 



(a) 69,820 



(b) 48,610 



(c) 21,210 



(d) 97-0 



(e) 92.2 

 (/) 2530 

 GO 86.5 

 (h) 91.3 



W 7-1 

 (?) 940 



7. "Find, by the K formulas, the voltage at the supply end of 

 the following line: 



Total length of line ................... 400 miles. 



Spacing ............................. 15 feet. 



Conductor .......................... No. oooo copper cable. 



Load at receiver end of line, 5000 K.V.A., 85% P.F. (lagging) 



110,000 volts, three phase, 60 cycles. 



Load taken by a substation at the middle of the line, 200 miles 

 from either end, 2500 K.V.A., at the line voltage and at 90% P.F. 



(lagging). 



Ans. 89,720 volts. 



[By the convergent series, 90,190 volts (Prob. 6, Chap. VI). Error 

 o.S%J 



A method of operation of transmission lines is coming 

 into prominence, by which the voltage of the line is kept 

 constant at all points, and the inconveniences due to poor 



