▁it ▁attempted ▁to ▁transfer ▁from ▁U AT ▁ 2 - B ▁( power ed ▁by ▁the ▁tur bine ▁generator ) ▁to ▁the ▁failed ▁R AT ▁ 2 - B , ▁causing ▁two ▁of ▁the ▁re actor ▁cool ant ▁p umps ▁and ▁one ▁of ▁the ▁main ▁feed water ▁p umps ▁to ▁trip . ▁Despite ▁this , ▁plant ▁cool - down ▁proceeded ▁safely . ▁At ▁ 9 : 0 3   p . m ., ▁the ▁R AT ▁ 2 - B ▁break ers ▁in ▁the ▁switch yard ▁were ▁reset ▁and ▁off site ▁power ▁was ▁restored ▁to ▁the ▁vital ▁and ▁non - v ital ▁" B " ▁elect rical ▁trains , ▁allowing ▁re actor ▁cool ant ▁p umps ▁ 2 ▁and ▁ 4 ▁to ▁be ▁restart ed . ▁ED G ▁ 2 - B ▁was ▁shut down . ▁It ▁was ▁later ▁determined ▁that ▁the ▁fault ▁disturb ance ▁caused ▁by ▁the ▁line ▁falling ▁was ▁not ▁of ▁significant ▁magnitude ▁to ▁trip ▁the ▁protect ive ▁relay ▁per ▁design ▁and ▁should ▁not ▁have ▁caused ▁Unit   2 ▁to ▁shut ▁down . ▁Further ▁investigation ▁found ▁that ▁current ▁transform ers ▁on ▁the ▁main ▁transform er ▁were ▁impro per ly ▁set . ▁The ▁controls ▁were ▁adjust ed ▁to ▁the ▁proper ▁setting . ▁Had ▁the ▁CT s ▁been ▁properly ▁set ▁initially , ▁the ▁Unit   2 ▁would ▁have ▁remained ▁online . ▁ ▁Units ▁ 3 ▁and ▁ 4 ▁ ▁Pl anning ▁phase ▁ ▁On ▁August ▁ 1 5 , ▁ 2 0 0 6 , ▁Southern ▁N uc lear ▁formally ▁applied ▁for ▁an