CURRENT-LIMITING REACTORS 



467 



where they, of course, mostly take place. Modern transformers 

 are, however, generally built with a comparatively high inherent 

 reactance, so that they can safely withstand short-circuits, and 

 reactors are, therefore, very seldom installed in this manner. 



Reactors in low-tension feeders (Fig. 292) are, however, very 

 common and have many advantages. The probability of a 

 short-circuit in a feeder is far greater than in any other part of 

 the system, and the short-circuit current through a feeder switch 

 may be considerable, since the current from all the generators will 

 pass through the same and possibly also the current from other 



o o o o 



FIG. 291. Transformer Reactors. 



O O O 



FIG. 292. Feeder Reactors. 



synchronous machines on the system. By means of feeder 

 reactors, however, such troubles may be still more limited than if 

 bus reactors were provided, and it is merely a question of cost 

 whether such reactors can be afforded. 



Feeder reactors, of course, only give protection for those short- 

 circuits which occur on the feeders beyond the point where they 

 are installed, and do not give protection to short-circuits which 

 occur on the busbars or in the generators, transformers or their 

 connections. 



Stott System. This scheme (Fig. 293) was proposed by tne 

 late Mr. H. G. Stott, of the Interborough Rapid Transit Company 

 of New York, and is now being quite extensively used in connec- 

 tion with large steam turbine-driven central stations. The 

 feeders are grouped and fed from different bus sections which are 

 individually energized by generators delivering current through 5 

 per cent reactors. The bus sections are normally operated sep- 

 arately but may be instantly connected by tie switches. To per- 



