The national power grid collapsed on Tuesday, the Transmission Company of Nigeria (TCN) has said.The spokesperson of the company said the incident occurred at 11:13am, and that restoration of the grid was over 90 percent already.TCN did not immediately state the reasons for the system collapse, saying it was still being assessed while taking actions to swiftly restore electricity supply nationwide.Daily Trust reports that the grid has had multiple disturbances this year, causing total outages and in some cases, partial outages.Between 2017 and 2019 the power Generation Companies (GenCos) connected to the National Grid were enforced by TCN to put their machines on Free Governor Mode of Operations to reduce the spare of system collapse. Records from TCN this year places reduction in system disturbances at 60 percent.However, a 240 megawatts (MW) spinning reserve TCN contracted with about seven GenCos to use to stabilize the grid before it collapses like that Tuesday, is still on hold. The Nigerian Electricity Regulatory Commission (NERC) was yet to approve the extraordinary tariff for TCN on the spinning reserve after it held consultations with members of the public on it in March 2020.