TRANSMISSION LINE 407 



IG lags behind E by an angle <f>", 

 where 



and IQ lags behind EG by an angle $G = <f>' + <",* 



tan , G = tan(,' + r ) =t 7= 0.132, 



and 0s = 7 30'; 







the power factor at the generator is 



cos <<? = cos 7 30' = 0.99 

 = 99%. 



The impedance drop in the line is found very approximately as 



E z = 7 Vr 2 + x 2 



= 117 V(68) 2 + (148) 2 = 19,000 volts 

 = 19% of the receiver voltage. 



The power loss in the line is found approximately as 



= (101.5) 2 34 + (117) 2 34 



= 814,000 watts 



= 814 kilowatts 



= 4.07% of the output. 



261. Three-phase Transmission Line. A three-phase trans- 

 mission line delivers 10,000 kv.a. at 60,000 volts and 60 cycles to 

 a receiving circuit of 85 per cent power factor; determine the 

 voltage and current at the generating station, the charging current 

 and charging kv.a. of the line and the power loss in the line. 

 Determine also the rise in voltage at the terminals of the receiving 

 circuit if full load is suddenly removed. 



Length of line = 77 miles. 



Conductor section = 426,000 cir. mils, aluminum. 

 Diameter of conductor = 0.653 inch. 

 Distance between conductors = 72 inches. 



