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Catastrophic optical damage (COD), or catastrophic optical mirror damage (COMD), is a failure mode of high-power semiconductor lasers.It occurs when the semiconductor junction is overloaded by exceeding its power density and absorbs too much of the produced light energy, leading to melting and recrystallization of the semiconductor material at the facets of the laser.
Possible causes for overcurrent include short circuits, excessive load, incorrect design, an arc fault, or a ground fault. Fuses, circuit breakers, and current limiters are commonly used overcurrent protection (OCP) mechanisms to control the risks. Circuit breakers, relays, and fuses protect circuit wiring from damage caused by overcurrent. [1]
Where a generating station is large compared to the connected grid capacity, any failure can cause extensive disruption within the network. A serious failure in a proportionally large hydroelectric generating station or its associated transmission line will remove a large block of power from the grid that may lead to widespread disturbances.
Load rejection in an electric power system is the condition in which there is a sudden load loss in the system which causes the generating equipment to be over-frequency.. A load rejection test is part of commissioning for power systems to confirm that the system can withstand a sudden loss of load and return to normal operating conditions using its governor. [1]
Any overload of a power line or generator can cause costly damage, so the affected device is disconnected from the network if an overload is detected. The electrical resistance of a power line causes it to produce more heat as the current it carries increases.
Idaho National Laboratory ran the Aurora Generator Test in 2007 to demonstrate how a cyberattack could destroy physical components of the electric grid. [1] The experiment used a computer program to rapidly open and close a diesel generator 's circuit breakers out of phase from the rest of the grid, thereby subjecting the engine to abnormal ...
Overspeed is a condition in which an engine is allowed or forced to turn beyond its design limit. The consequences of running an engine too fast vary by engine type and model and depend upon several factors, the most important of which are the duration of the overspeed and the speed attained.
Diesel engine runaway is an occurrence in diesel engines, in which the engine draws extra fuel from an unintended source and overspeeds at higher and higher RPM, producing up to ten times the engine's rated output until destroyed by mechanical failure or bearing seizure due to a lack of lubrication. [1]