CHAPTER VI 



ADVANTAGES AND DISADVANTAGES OF THE CONSTANT- 

 VOLTAGE SYSTEM 



SINCE voltage variation imposes the limit of the load 

 of a transmission line as ordinarily operated according 

 to the varying-voltage method of control, lines are gen- 

 erally designed, for the sake of economy, to have as 

 great a voltage variation as is allowable. Therefore, 

 when the load is as large as was planned, the voltage 

 variation is often found to be the most troublesome oper- 

 ating feature. Other troubles, as from lightning, may be 

 more serious, but they are occasional; voltage variation 

 is always present. Thus it is obvious that by installing 

 synchronous motors, or phase modifiers, and so practi- 

 cally doing away with voltage variation, the operation 

 of the power system is made more easy and satisfactory. 

 Moreover, it is possible to furnish a steadier voltage to 

 all the customers than is often obtainable where the 

 voltage is adjusted only at the generators. This results 

 in greater economy of operation and less damage from 

 excessive voltage to all kinds of electrical apparatus. 

 There is, consequently, greater satisfaction with the 

 power service, and power is easier to sell. Also, since the 

 voltage does not drop on the occurrence of peaks in the 

 load, more energy is registered by the meters and the 

 income is increased. The operating advantages of con- 

 stant voltage are, therefore, not without a definite cash 

 value. 



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