PowerGrid posts biggest intraday gain in over 2 weeks

HYDERABAD (AP) -31-07-2012 - BL/ STAND ALONE PIC : POWER GRID FAILURE HITS INDIA FOR THE SECOND DAY : India's power grid divided into five zones - the North , East , South , West and North East was disrupted for the second day consecutively . The grid meant to optimally utilise the unevenly distributed power resources tripped in the Northern and Eastern regions hitting power utilities in New Delhi , NCR , Uttar Pradesh , Haryana , West Bengal , Assam and Punjab .The grid frequency falls when there is excess drawl of electricity or the generation is less and increases when there is excess supply or the drawal is less. The grid is a network of power lines that evacuates electricity from a generating station. A grid collapses when the frequency falls below the lower limit of the (49.5-50.2Hz) band or increases beyond the upper limit. As a result, transmission lines stop accepting power supply and other grid constituents, including the generating stations, go offline. Photograph shows transmission line grid from the NTPC , Ramagundam Power Station in Karimnagar District of Andhra Pradesh . PHOTO: P_V_SIVAKUMAR .