Aug, 2005 THE US BLACKOUT AUGUST 14, 2003

Aug, 2005 NORTH AMERICAN GRID INTER-CONNECTS THE INDIAN GRID AT PRESENT IS ALSO SIMILAR WITH THE SOUTHERN REGION ELECTRICALLY ON A DIFFERENT GRID - WITH REST OF INDIA ON A SINGLE GRID ELECTRICALLY INDEPENDENT CONNECTED BY SMALL HVDC LINES

Aug, 2005 AUG 14, 2003 –DISTURBANCE IN NE US ALL OPERATORS ARE ENGINEERS AND ARE HIGHLY EXPERIENCED. UNIFIED MODEL COVERS ENTIRE AREA, HENCE OPERATOR SEES ALL CONTINGENCIES AND IS PREPARED FOR REPURCUSSIONS IN HIS CONTROL AREA ULDC DESIGNED WITH ‘EVERY ONE CAN SEE EVERYTHING’ POLICY – FULL TRANSPARAENCY – SYNERGY IN ACTIONS – TRUST – FASTER RETURN FROM EMERGENCY SITUATIONS AGGRESSIVE VEGETATION MANAGEMENT – LOCAL CREW – POWERGRID HAS TAKEN UP SEB’S MAINTENANCE OF CRITICAL LINES IN FOREST/TOUGH TERRAIN – REGULAR LINE PATROLS – ADEQUATELY STAFFED AND EQUIPPED WITH STATE OF ART DIAGNOSTIC EQUIPMENT APEX BODY CONTINUALLY CO-ORDINATING – GETS ALL REAL TIME DATA – HOT LINE COMMUNICATION LINKS MAJOR CAUSES FOR US BLACKOUT HOW WE ADDRESS THEM

Aug, 2005 Disturbances in the past Date/ Area MW Lost, Duration Causes (Trigger) Critical Phenomenon Nov. 1978/ France 30,000MW 7 hr - Major 400kV lines trips due to overloading - Voltage collapse - System separation Aug. 1981/ UK 1,900MW 2.5hr - Loss of 3 400kV circuits and lower voltage interconnection - System separation Jan. 1987/ France 8,000MW 3 hr - Multiple generator trips - Voltage collapse Jul. 1987/ Tokyo 8,000MW 4 hr - Insufficient VAR supply for high rate of load pickup - Voltage collapse Jul./Aug. 1996/ Western US 11,850MW ? hr 28,000MW 9 hr - Loss of multiple lines and loss of critical generation - Voltage collapse - System separation - Power oscillation

Aug, 2005 Disturbances in the recent past Date/ Area MW Lost, Duration Causes (Trigger) Critical phenomenon Aug Northern US 61,800MW 42 hr - Multiple line trips - Voltage collapse - System separation Aug London 724MW 0.7 hr - Incorrect operation of a backup relay - Overloading Sep Italy 20,000MW 20 hr - Multiple EHV line trips - Voltage collapse - Power oscillation - System separation Sep Scandia 6,550MW 6.5 hr - Scrum of a Nuke plant - Double-bus fault - Voltage collapse - Power oscillation May Moscow 2,500MW 32 hr - CT explosion - Multiple Tr. Explosion & Fire - Overloading

Aug, 2005 Cause and effect

Aug, 2005 ANATOMY OF A DISTURBANCE QUICK AND CONCERTED OPERATOR ACTION – REFINED OPERATING RULES – ROBUST COMMUNICATION – MOCK DRILLS UNDER FREQUENCY RELAYS, RATE-OF-FREQ RELAYS AT DIFFERENT BANDS ISLANDING SCHEMES. SPECIAL PROTECTION SCHEMES ‘BEST PRACTICE’ MAINTENANCE – PRACTIVE INVESTMENT IN MAINTENANCE – NO SHORTCUTS

Aug, 2005 Major Grid Disturbances During Recent Past CountryDisturbance USAAugust’03 UKAugust’03 CanadaAugust’03 SwedenSeptember’03 DenmarkSeptember’03 ItalySeptember’03

Aug, 2005 LOW DEMAND(VALLEYS)SHARP PEAKS 0000 HRS OF 01 SEP AUG 0630 AUG 0631 AUG 06