CAPACITY OF SINGLE-PHASE LINE 



. 

 dx 



(Fig. 24) and the capacity of the entire system of four wires 

 is then calculated as follows: 



Let h be the distance of the 

 wires from the ground and s 

 their distance apart from center 

 to center. Let A carry a charge 

 of -h q units per centimeter; A', : 

 - q units; B, q units; and 

 B', + q units. Let a unit charge 

 be carried from the surface of 

 A to that of B. Assuming that Fig 24 



the charges are concentrated at 

 the centers of the wires, the total work done is equal to 



!r+T e ^r x dx - f 



A/ t/p O As i/ p 



~ p 2 q (s x) 



2 qx 



t dx 



r 



dx. 



The sum of the first two integrals has been shown to be 

 approximately 



4?loge-. 

 P 



The sum of the last two integrals is approximately 



Therefore, the total work is equal to 



+ lo - - 2k 

 p 



