CHAPTER V. 



K FORMULAS. 



WHEN a transmission line is more than 20 miles long, 

 the formulas for short lines given in Chapter IV are no 

 longer accurate, and other formulas must be used, which 

 will take into account the capacity of the line. Such 

 formulas, called K formulas, will be found in Tables III 

 and IV, pp. 28 to 35. The same tables will be found in 

 Part III at the end of the book. 



The K formulas will be found very similar to those of 

 the last chapter, and while they require more arithmet- 

 ical work, they should not be found any more difficult to 

 understand. No more values of line constants need to be 

 looked up for the K formulas than for the " Short Line" 

 formulas. The capacity of the line does not enter into the 

 calculations, since its effect is allowed for by means of the 

 constant K which is the same, at any one frequency, for 

 all values of line capacity. 



The formulas of this chapter assume that the leakage 

 current is zero; that is, that no power is lost from leakage 

 over the insulators or from corona. This is a correct 

 assumption to make for all voltages except the very highest 

 in use. If it is desired to make allowance for corona loss, 

 the formulas of Chapter VI should be used. 



The accuracy of the K formulas is given as approxi- 

 mately YO f I % f I* 116 voltage for lines up to 100 miles 

 long and with regulation up to 20%, and as J of i% for 

 lines up to 200 miles long, and with the same regulation. 



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