I expect you to mention at least the following aspects in your report:
What are the reasons for the blackout ?
Regions and the number of customers affected due to the blackout.
Aftermath of the blackout.
Any measures proposed to prevent future blackouts and improve the reliability of the power grid.
In addition to wikipedia I found the following references to be very useful.
[History],” in IEEE Power and Energy Magazine, vol. 15, no. 3, pp. 84-96, May-June 2017.
Power and Energy Magazine, vol. 4, no. 5, pp. 90-95, Sept.-Oct. 2006.
Following the 2003 North American Blackout,” in IEEE Power and Energy Magazine, vol