The Glade 4.0

Findings
In February 2004, the U.S.-Canada Power System Outage Task Force released their final report, placing the causes of the blackout into four groups:[13]

First, that FirstEnergy (FE) and its reliability council "failed to assess and understand the inadequacies of FE’s system, particularly with respect to voltage instability and the vulnerability of the Cleveland-Akron area, and FE did not operate its system with appropriate voltage criteria".

Second, that FirstEnergy "did not recognize or understand the deteriorating condition of its system".

Third, that FirstEnergy "failed to manage adequately tree growth in its transmission rights-of-way".

Finally, the "failure of the interconnected grid's reliability organizations to provide effective real-time diagnostic support."

The report states that a generating plant in Eastlake, Ohio (a suburb of Cleveland) went offline amid high electrical demand, putting a strain on high-voltage power lines (located in a distant rural setting) which later went out of service when they came in contact with "overgrown trees". The cascading effect that resulted ultimately forced the shutdown of more than 100 power plants.

This trip caused load to transfer to other transmission lines, which were not able to bear the load, tripping their relays. Once these multiple trips occurred, multiple generators suddenly lost parts of their loads, so they accelerated out of phase with the grid at different rates, and tripped out to prevent damage.