Critters vs. High Voltage Power Equipment
At electric utilities, we understand that the high voltages that we utilize in order to move electricity over the long distances from where it is generated to where it is needed are dangerous. Our lineworkers are very highly trained in what it takes to work on this equipment safely and efficiently in such a way that our customers usually never even know that anything happened, and we have engineers on staff to ensure that our systems are designed in such a way that they work effectively and keep the public safe, even when things don't go right. We bury our lines or put them quite a ways up in the air so that they're not easily accessible, we put wildlife covers on as much as can be covered up, and we fence in our substations where things do come close to the ground.
But, even with all of that, things can still go wrong. Most commonly, this comes in the form of an animal. Whether large or small, animals are some of the most curious and determined creatures on this planet. They will see something that looks interesting or like it could have food in it and they will crawl to it, crawl on it, dig at it, and otherwise work their way into things in or on which they have no business. And, once they get there, they almost never get the opportunity to learn that electricity is not forgiving, nor is it gentle. The gallery below shows one such raccoon that didn't get to learn this lesson.
Please note: This gallery is not for the squeamish or faint-of-heart!
Houston, we have a problem...
Here we have the initial view of the problem. You are looking at a couple of substation Oil Circuit Reclosers (called OCRs, essentially 7,200 volt circuit breakers that try to re-energize the line a few times after they trip before giving up and leaving the power out), one of which has a problem.
This is what a Cooper VWE OCR normally looks like in a substation. Note the plastic covers over the bushings. These covers are fastened over top of the bolted connections between the bushings (where the electricity enters and exits the OCR) and the wires that carry the electricity out of the substation and are intended to keep wildlife out of the energized parts.
This is what a Cooper VWE OCR looks like after a raccoon crawls up in between the bushings and manages to break into the wildlife covers.
Closeup View - North
Closeup view of the raccoon and top of the recloser from the north side. Note that the energy of the fault, once the raccoon touched energized parts, blew several "skirts" off the porcelain bushings.
Closeup View - Northwest
Closeup view from the northwest side of the OCR.
Closeup View - Northeast
Closeup view from the northeast side of the OCR.
View from the south side of the recloser.
These pictures are from the Akron Substation south of Akron, Colorado. The raccoon climbed onto Y-W Electric Association's Circuit #8 OCR inside the substation, apparently to pick at some debris and/or bugs that had accumulated underneath the bushing covers that are supposed to protect against animal contacts. Because this fault occurred electrically ahead of the OCR, the circuit switcher on the high side of WAPA's transformer tripped, interrupting power supply to the whole substation and plunging the Town of Akron and the surrounding areas into darkness at 10:25 PM, March 12, 2007. With almost no light from the moon that night, it was really, really dark.
This is a view of the damaged recloser as seen from the load side of the unit. This is the same view that was presented from the south while the recloser was still installed in the substation.
This is a view of the damaged recloser as seen from the source side of the unit. This is the same view that was presented from the north while the recloser was still installed in the substation.
This is a view of the damaged recloser as seen from the end where the control attaches to the unit. This is the same view that was presented from the northeast, where the raccoon's tail and back legs were laying.
This is a view of the damaged recloser as seen from the end opposite where the control attaches to the unit. Notice the damage even to the back side of the bushings and head from where the raccoon was.
A Lot of Heat
This picture shows the damage to the stainless steel bolts on the opposite side of one of the source-side bushings from where the raccoon was located. This damage leads me to believe that the entire top of the recloser must have been one ball of plasma when this event occurred.