A reader saw yesterday’s 500 kV interrupter arc video and pointed us to this amazing 1993 video footage of Miami’s Ives Dairy power substation failing in absolutely spectacular fashion. Unlike a lot of YouTube “disaster” footage, this clip from user gobo760 is extremely well annotated:
…a huge power surge on the Miami grid fried one of the capacitor banks, and caused a breaker to trip open when that rush of unregulated power went through…Unfortunately, the breaker malfunctioned and created an arc fault (a continuous lightning bolt that acted like an uncontrollable welding torch from hell) between the hot side of the breaker and wherever it could find a ground to complete the circuit, thus pulling far more current then the facility was designed for…the emergency response system that would have notified the grid dispatcher of a serious problem (who would have then cut the power to the substation and neighborhood to kill the arc fault) was inoperative, and no message was ever sent…The uncontrolled arc fault caused the coolant (mineral oil) inside the primary transformer to overheat to critical levels until it was boiling in a highly flammable state. This boiling caused pressure to rise inside the transformer (like a pressure cooker) until the seals finally blew. Mineral oil vapor proceeded to pour out at that point (the plume of white fog at the end) which ignited on the arc fault. The flames caused by this immediately ignited back to the source, (the boiling transformer tank), which ignited the mother load of oil inside causing the substation to explode in a giant ball of fire. The sudden loss of all transformer coolant resulted in a simultaneous flash-meltdown of the transformers innards, which immediately caused the main high voltage fuse to overload and blow (the loud explosion at the end), finally killing the arc…
There’s a lot more detail, and it’s worthwhile to click through and read the whole thing. [Thanks, Kevin!]
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