CHAPTER X 



COST COMPARISONS 



IN order to show the possibilities of money-saving in 

 power-factor control, estimated first costs are given for 

 several examples. These comparisons are meant to 

 bring out the general fact that for very long lines the 

 saving may amount to a large proportion of the cost of 

 the line, while for moderate distances the saving is much 

 less, except where the voltage used is unusually low. It 

 is, of course, impossible to assign unit costs which will 

 be precisely equal to those encountered in any given part 

 of the country. However, even if the costs given differ 

 widely from those which ought to be used in a certain 

 case, still they indicate under what conditions the 

 constant-voltage system is worth while merely for re- 

 ducing line costs, and where it is necessary to depend 

 also on other advantages, and to make use of synchro- 

 nous motors which also do other work than adjust the 

 power-factor. 



The general method which has been used for making 

 the comparison of costs will be found the most suitable 

 for making a first estimate. The largest item which has 

 been omitted is the cost of land. This must be estimated 

 for each separate case, since the cost of land varies ex- 

 tremely in different localities. It has been stated in an 

 authoritative paper on transmission-line construction * 



* "Design of Transmission Lines," by Julian C. Smith, Trans. 

 Can. Soc. C. E., October, 1912. 



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