Separation of Transformers for Class 1E Systems in Nuclear Power Plants

Table 7

The result of the modified electric power system short circuit current analysis.

Power source	4.16 kV bus	Cat. I	Cat. II	Cat. III	Cat. IV	Cat. V
UAT1	Non-Class 1E	36.7 kA	40.9 kA	40.0 kA	40.0 kA	40.9 kA
	Bus A
	Non-Class 1E	26.8 kA	26.8 kA	26.8 kA	26.8 kA	26.8 kA
	Bus B
UAT2	Class 1E	21.7 kA	18.6 kA	21.6 kA	19.6 kA	27.3 kA
	Bus A
	Class 1E	22.2 kA	18.9 kA	21.8 kA	19.8 kA	27.3 kA
	Bus B
SAT1	Non-Class 1E	—	41.4 kA	41.1 kA	40.0 kA	41.4 kA
	Bus A
	Non-Class 1E	—	28.1 kA	28.1 kA	26.8 kA	28.1 kA
	Bus B
SAT2	Class 1E	—	13.3 kA	16.5 kA	19.6 kA	21.6 kA
	Bus A
	Class 1E	—	13.5 kA	16.5 kA	19.8 kA	21.6 kA
	Bus B

the plant start-up condition (Cat. I), the electric power system receives power only through UAT1 and UAT2.