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A cascading failure is failure in a system of interconnected parts, where the service provided depends on the operation of a preceding part, and the failure of a preceding part can trigger the failure of successive parts. Redundant parts can lessen the impact of, but not prevent, a failure.

Contents 1 Cascading failure in power transmission 2 Other examples of cascading failure 3 Examples 4 See also 5 External links

Cascading failure is common in power grids when one of the elements fails (completely or partially) and shifts its load to nearby elements in the system. Those nearby elements are then pushed beyond their capacity so they become compromised and shift their load onto other elements. Cascading failure is a common effect seen in high voltage systems, where a single point of failure (SPF) on a fully loaded or slightly overloaded system results in a sudden spike across all nodes of the system. This surge current can induce the already overloaded nodes into failure, setting off more overloads and thereby taking down the entire system in a very short time.

This failure process cascades through the elements of the system like a ripple on a pond and continues until substantially all of the elements in the system are compromised and/or the system becomes functionally disconnected from the source of its load. For example, under certain conditions a large power grid can collapse after the failure of a single transformer.

Monitoring the operation of a system, in real-time, and judicious disconnection of parts can help stop a cascade.^{[citation needed]} Another common technique is to calculate a safety margin for the system by computer simulation of possible failures, to establish safe operating levels below which none of the calculated scenarios is predicted to cause cascading failure, and to identify the parts of the network which are most likely to cause cascading failures.^{[citation needed]}

Analogues to this exist in biology of cascade-like effects where a small reaction can have system-wide implications. One example to this is the release of toxins caused by a small ischaemic attack, which kill off far more cells than the initial damage, resulting in more toxins being released. Current research is to find a way to block this cascade in stroke patients to minimise the damage.

The common Cockcroft-Walton generator is another example of cascade failures, where one failed diode can result in all the diodes failing in a fraction of a second.

Another example of a cascading failure in a scientific experment was the implosion in 2001 of several thousand fragile glass photomultiplier tubes used in the Super-Kamiokande experiment, where the shock wave caused by the failure of a single detector appears to have triggered the implosion of the other detectors in a chain reaction.

• Northeast Blackout of 1965
• Northeast Blackout of 2003
• 2003 Italy blackout

• Byzantine failure
• Chain reaction
• Congestion collapse
• Cascading rollback

• Space Weather: Blackout - Massive Power Grid Failure
• Monash University VLAB cascading failure program in Java - Alex Tee Neng Heng and David Green
• A. E. Motter and Y.-C. Lai, Cascade-based attacks on complex networks, Physical Review E (Rapid Communications) 66, 065102 (2002).
• Protection Strategies for Cascading Grid Failures — A Shortcut Approach
• Ian Dobson, Benjamin A. Carreras, and David E. Newman, preprint A loading-dependent model of probabilistic cascading failure, Probability in the Engineering and Informational Sciences, vol. 19, no. 1, January 2005, pp. 15-32.
• Nova: Crash of Flight 111 on September 2, 1998. Swissair Flight 111 flying from New York to Geneva slammed into the Atlantic Ocean off the coast of Nova Scotia with 229 people aboard. Originally believed a terrorist act. After $39 million investigation, insurance settlement of $1.5 billion and more than four years, investigators unravel the puzzle: cascading failure. What is the legacy of Swissair 111? "We have a window into the internal structure of design, checks and balances, protection, and safety." -David Evans, Editor-in-Chief of Air Safety Week.
• PhysicsWeb story: Accident grounds neutrino lab