CORRECTED - PG&E Calif. Helms 2 hydro unit back in service

(Corrects number of unit that returned to service) NEW YORK, Feb 2 (Reuters) - PG&E Corp's (PCG.N The company shut the unit by Jan. 26 for planned reasons. The 1,212 MW Helms station, which entered service in 1984, is located near Fresno...