CURRENT-LIMITING REACTORS 



477 



reactances given for the different apparatus and circuits. Those 

 values should preferably be expressed in per cent, based on some 

 nominal capacity such as the capacity of the principal generating 

 unit as previously explained. The procedure of calculation is 

 best explained by an example : 



Assume a network, as shown in Fig. 295. The various por- 

 tions of the circuit have the per cent reactance indicated, all based 



Sta. No. 1 



3.M* 



Sub. Sta, 



3.03* 



/V*V\ 



NAfv 



L53* 



3.0* 



Sub. SU. 



IMt 



/vv\7 II 



5^1.1% 

 *M 



Sta. No. 2 



FIG. 295. Typical Connection of a Simple Transmission System. 



on 10,000 Kv.A. Stations No. 1 and 2 are generating stations, 

 each containing a number of generators with a combined reac- 

 tance, as shown. For a three-phase short circuit at A, the short 

 circuit Kv.A. is found as follows: 



6.2+3 = 9.2 

 3.3+1.52 = 4.82 



1 =3.16 



9.2 ' 4.82 



