Examples of network failures

摘要

Northeastern United States, 1965: On Nov. 9. power was disrupted to parts of Ontario, Connecticut, Massachusetts, New Hampshire. Rhode island, Vermont, New Jersey, and New York. More than 30 million people were without electricity tor up to 12 hours, all due to an error in setting up a protective relay in the network. An interconnecting transmission line between the Niagara Falls (N.Y.) hydro generating station and Ontario was tripped offline, while it was operating well below its rated capacity. The loads that were being served by this tine were transferred to another transmission line, causing it to overload and trip offline. This created a major power surge due to excess capacity on the Sir Adam Beck generating station, which reversed the direction of power flow on other transmission lines crossing into New Yort. While the Robert Moses plant (Niagara Falls generating station) isolated itself from the surges, the network disruptions cascaded throughout New York and the other Northeast states. There were alternating overloaded transmission lines and power generating stations tripping offline to protect themselves from damage due to the power surges. During this event, the network frequency dropped to 56 Hz and, 1 minute before the blackout, down to 51 Hz.