22 TRANSMISSION LINE FORMULAS 



PROBLEM A. 



Find the regulation of the following single-phase line: 



Length of line ....................... 15 miles. 



Spacing ..................... ........ 3 feet. 



Conductor .......................... No. o copper wire. 



Load (at receiver end), 300 K.V.A., 11,000 volts, 50% P.F., single 



phase, 60 cycles. (Same as Prob. D, Chap. III.) 

 From the tables in Part III, 



r = 0-5331- 

 x = 0.686. 



P = looo X 300 X 0.50 = 6 



11,000 



X 300 X 0.866 = 62 



11,000 



A = 11,000 + 2 X 13.64 X 0.5331 X 15 



+ 2 X 23.62 X 0.686 X 15 

 = 11,704. 

 B = 2 X 13-64 X 0.686 X 15 - 2 X 23.62 X 0.5331 X 15 



= ~ 9? * 



Per cent regulation = I0 ( 11,704+ 97 X 9 ? -- u,ooo ) 

 11,000 \ 2 X 11,704 / 



= 6.40%. 



PROBLEM B. 



Calculate the volts drop for the following case, where all the 

 conditions are specified at the supply, or generator, end of the line: 

 Length of line ........................ 10 miles. 



Spacing .............................. 3 feet. 



Conductor ........................... No. 2 copper wire. 



Quantities measured at supply end: 600 K.V.A., 6600 volts, 

 80% P.F., three phase, 60 cycles. 



From the tables in Part III, 



r = 0.8469. 



3-0.714. 



