Electricity: Blackout as national grid experiences system collapse On By Prince Okafor The national grid again, yesterday, suffered another systems collapse, worsening the power supply situation in the country. Vanguard gathered that the system collapse occurred, following voltage collapse in some parts of the national grid The national grid is controlled and operated by government-owned Transmission Company of Nigeria, TCN. Power system collapse is the process by which the sequence of events accompanying voltage instability leads to an unacceptable voltage drop in a significant part of the power system. Vanguard learned that the collapse occurred around 11.01 am yesterday. Confirming the development, TCN General Manager, Ndidi Mbah, told Vanguard that at about 11`.01am yesterday, there was total system collapse of the grid, as a result of voltage collapse at some parts of the grid.