DUKE POWER 99 ISLANDS HYDROELECTRIC PLANT 6 UNITS 19MW

TWIN HEADGATE REPLACEMENT FOR THE EXISTING WOODEN TIMBER HEADGATE

99 ISLANDS WAS ORIGINALLY CONSTRUCTED IN 1911. EACH UNIT HAS A 16'8" WIDE X 20' TALL WOODEN TIMBER HEADGATE FOR DEWATERING THE TURBINE. THE EXISTING OPERATING MECHANISMS CONSISTED OF A SERIES OF JACK-SHAFTS, CAST IRON GEAR REDUCTION, AND RACK AND PINION LIFTING BEAMS. 

DUKE POWER CONTRACTED WITH NORTH FORK ELECTRIC INC. TO DESIGN AND BUILD A UNIQUE SELF-SUPPORTING TWIN HEADGATE REPLACEMENT. 

THE REPLACEMENT DESIGN IS OF MODULAR DESIGN FOR EASE OF SHIPPING AND ASSEMBLY. ALL STEEL IS FULLY HOT DIPPED GALVANIZED AND EACH GATE HAS CONTINUOUS RUBBER "J" SEALS . EACH GATE HAS A 50 TON RATED SCREW-JACK AND IS CAPABLE OF CLOSING UNDER FULL DIFFERENTIAL.