coi rate day ahead market ran coi branch group ttc n direction changed 4020 mw 4300 mw n direction changed 2450 mw 3675 mw 2100 2400 operating day 8 13 01 reason change line work finished applies real time iso update changes line rating status sent market operations inquiries please call hour ahead desk system conditions described communication dynamic subject change iso attempted reflect current accurate information available preparing notice system conditions may change suddenly little notice