Mumbai: Preliminary report released by the Power System Operation Corporation (POSOCO) clearly said the total reduction in all-India demand recorded during the nine minutes light switch-off was 31,089 mw. All-India demand started reducing from 8.45 pm and a minimum demand of 85,799 mw was recorded at 9.10 pm.
Subsequently, from 9.10pm, the demand started to pick up and settled around 1,14,400 mw at 10.10pm. Grid Frequency during the event remained in the range of 50.26 Hz to 49.70 Hz with maximum and minimum frequency of 50.259 Hz and 49.707 Hz recorded at 8.49 pm and 9.08 pm respectively.
Slew of actions taken were included hydro generation across the country was maximised by 8.45 and generation reduction of 17,543 mw (from 25,559 mw to 8,016 mw) between 8.45 pm to 9.10pm (matching with demand reduction of 31,089 mw during the same period) was achieved with these resources; this hydro generation was again ramped up from 8,016 mw to 19,012 mw from 9.10 pm to 9.27 pm to meet the increase in demand after the event; reduction of total 10,950 mw generation was achieved through thermal (6,992 mw), gas (1,951 mw) and wind generation (2,007 mw) during 8.45 pm to 9.10pm; advance actions such as switching off transmission lines, taking reactors in service, changing SVC, STATCOM, HVDC set points were taken prior to the event for keeping voltages and line loadings within permissible limits. The event was managed smoothly.