372 ELECTRICAL EQUIPMENT 



ties not encountered in low-voltage work. In the latter case the 

 energy loss is generally the limiting factor and the regulation can 

 often be improved by installing larger conductors, which at the 

 same time will reduce the line loss. With high-voltage systems 

 the gain of doing so is very slight and other means must be resorted 

 to for keeping the regulation within commercial limits. The 

 effect of the inductance and capacity of the line causes the voltage 

 to vary within very wide limits from full to no load. At no load 

 the large capacity current causes a rise of voltage from the gener- 

 ating station to the receiving end, while at full load the lagging 

 inductive current taken by the load, in general, more than offsets 

 the effect of the capacity current and causes a drop of voltage 

 from the generating station to the receiving end. It is evident 

 then that by installing a synchronous condenser at the receiving 

 end and by taking advantages of the characteristics of this ma- 

 chine, the receiving voltage can be kept constant at a determined 

 value or approximately so, by adjusting the synchronous con- 

 denser field causing the condenser to draw a lagging current from 

 the line at no load and a leading current at full; thus, by varying 

 the power-factor. 



The automatic regulation of the condenser field current is 

 readily accomplished by means of a T.A. regulator. In this 

 instance the regulator does not, therefore, hold a constant power- 

 factor, but, by varying the same, holds a constant A.C. voltage 

 provided there is the proper capacity in the synchronous con- 

 denser upon which it is operating. The regulator endeavors to 

 hold just as much leading current upon the condenser as there is 

 lagging current upon the main transmission line; or else it will 

 endeavor to maintain the proper lagging current to counteract 

 for any leading current that exists upon the transmission system. 

 The connections and adjustment for the regulator are the same 

 as when being used upon an A.C. generator with the exception 

 that greater care should be exercised in the adjustment. 



In a system of this kind, if the synchronous condenser has not 

 ample capacity, there is danger of burning out the fields, due to 

 the fact that the regulator is trying to maintain constant A.C. 

 voltage upon the system. It is very important, therefore, that 

 the highest safe voltage at which to operate the condenser fields 

 be determined, and the regulator adjusted for this limiting value, 

 which may be about 135 volts for a 125-volt excitation. 



