Event analysis for the 7 april 2015 Washington, D.C., area low voltage disturbance

On April 7, 2015, at 12:39, a fault occurred outside the Washington, D.C. metro area that lasted approximately 58 seconds, initiated by failure of a surge arrestor on a 230kV transmission circuit and accompanied by a protection system failure. This resulted in about 532 MW of customer load lost. Load was restored to most customers within an hour; however, the impact on D.C. metro area made this eve nt more visible and noteworthy to the general public. Forensic event analysis, lessons learned, and areas for future focus for the electric utility industry are presented in this paper.