Click on image for a 1.25 MB MPEG

I recently received new information regarding this video from Wally Groff, a Journeyman Operator at Bonneville Power Administration (BPA). This video was captured in 2002 at a BPA substation located at the Haskill tap of the Libby-Conkelley No.1 230 kV transmission line near Kalispell Montana by Wally's supervisor. It shows a three phase vertical break disconnect switch attempting to de-energize an unloaded 34 mile long section of transmission line. This switch was part of an experimental design and is no longer in service. Air break disconnect switches are not intended to actively switch load current. In the above clip, the arcing is due to the attempted interruption of comparatively low reactive (capacitive or "charging") currents drawn by the open transmission line. Even with the reduced current, the disconnect switch was not always capable of opening the circuit. At the very end of the clip, a brief phase-to-phase power arc causes the upstream line interrupters to open, finally extinguishing the arcs.  Wally was also kind enough to provide the following image of another disconnect switch that failed to open properly. This was a 115 kV quick break disconnect that had exceeded it's switching capability while attempting to de-energize a 24 mile section of transmission line at a BPA facility near Tillamook, Oregon. At times the disconnect switch operated properly, but not on this day. As can be seen, one phase successfully disconnected, but the other two phases did not. Luckily the operator was able to reclose the disconnect before it relayed out. Click for larger image

This is the record holder for the world's largest unintentional Jacob's Ladder!  This video clip was captured by Neil Brady, the maintenance foreman of the 500 kV Eldorado Substation near Boulder City, Nevada at the time of the event. It shows a three-phase motorized air disconnect switcher attempting to open high voltage being supplied to a large three phase shunt line reactor. The line reactor is the huge gray transformer-like object behind the truck at the far right at the end of the clip.  Line reactors are large iron core coils (inductors) which are used to counteract the effects of line capacitance on long Extra High Voltage (EHV) transmission lines. Internally, this line reactor has three coils, one for each phase in the three-phase system. Each coil within the reactor can provide 33.3 Million Volt Amperes of compensating inductive reactance (MVAR) at 290 kV between each phase to ground .  The power company had previously encountered difficulty interrupting one of the three phases when trying to disconnect the line reactor. The substation maintenance crew set up a special test so that they could videotape the switching event, and they made arrangements to "kill" the experiment, if necessary, by manually tripping upstream circuit breakers. This particular switcher uses gas filled switching elements, called "gas puffer" interrupters (circuit breakers). These are located just to the right of the rotary air break switches. The actual switching elements of these interrupters are hidden inside the gray horizontal insulators (bushings).  The switching elements are housed within sealed "bottles" filled with a special insulating gas (sulfur hexafluoride, SF6) under high pressure. SF6 helps to rapidly extinguish ("quench") the arc that's created when the high voltage circuit is broken. During normal operation, the switcher will first open the SF6 interrupters which disconnects the HV circuit so that the air break switches can open with no current flowing. Once the air break switches completely rotate to the "open" position, the SF6 interrupters then reclose. Normally, this sequence insures that the air break switches operate de-energized and arc free. These gas puffer interrupters use two SF6 bottles that are connected in series, since it takes two switches to withstand the high voltage stress. In this video, one of the pairs of SF6 interrupters is defective and it fails to open. This places the entire voltage stress across the remaining good interrupter. As the good one valiantly tries to open the inductive load, it creates a high voltage surge that causes the bushing of the good interrupter to flash over. The initial flashover can be seen arcing across the horizontal interrupter bushing at the very beginning of the video clip. Since the affected phase remains energized (through the flashover arc), the air break switch begins to open while still "hot" (energized). It continues arcing as the switch rotates 90 degrees to the fully "open" position.  Once the air break switch reaches the fully open position, the SF6 interrupters then reclose. Although this extinguishes the horizontal arc across the good interrupter's bushing,  the arc across the air break switch persists, continuing to grow and creating a potentially dangerous situation. The arc stretches upward, driven by rising hot gases and writhing from small air currents, until it easily exceeds 100 feet in length. Switching arcs usually terminate long before reaching this size since they normally flash over to an adjacent phase or to ground. Once this happens, the phase-to-phase fault current will cause an upstream circuit breaker to trip, disconnecting the circuits. A phase-to-phase arc can be seen at the very end of the previous 230 kV air break switch video, just before the resulting short circuit trips upstream Oil Circuit Breakers (OCB). Since the 500 kV arc was in open air and was sufficiently removed from adjacent phases, it could have persisted for quite some time. To avoid risking further damage to their equipment, the utility manually commanded the upstream circuit breakers to open, abruptly extinguishing the arc. After this event, it was determined that both SF6 switch bottles in the affected phase had sustained permanent damage. The bottles were sent back to the manufacturer for analysis to determine the root cause of the problem. Loss of pressurized SF6 gas inside one of the interrupter bottles is suspected as the root cause of the initial switching failure. As impressive as this huge arc may be, the air break switch was really NOT disconnecting a real load. This arc was "only" carrying the relatively low (about 100 amps) magnetizing current associated with the line reactor. The 94 mile long transmission line associated with the above circuit normally carries over 1,000 megawatts (MW) of power between Boulder City, Nevada (from the generators at Hoover Dam) to the Lugo substation near Los Angeles, California. A break under load conditions (~2,000 amps) would have created a MUCH hotter and extremely destructive arc. Imagine a fat, blindingly blue-white, 100 foot long welding arc that vaporizes the contacts on the air break switch and then works its way back along the feeders, melting and vaporizing them along the way.  Still, you've got to admit that this "little" 33 MVAR  arc is certainly an awesome sight! And, who says utility guys don't have any fun - just listen to one of the maintenance crew guys on the right "whoop" at the end of the clip!

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This was an electrical substation that stepped down high voltage (138,000 volts) from a transmission line down to a lower voltage (23,000 volts) for local distribution. It was conveniently located adjacent to a golf course and residential housing. In this clip, a ground fault on a capacitor bank on the low voltage side of the substation creates an arcing fault that behaves like an uncontrollable welding torch from Hell, chewing up everything in its path. Normally, the abnormal current would be detected and power automatically removed almost immediately by substation protective hardware. Unfortunately, in this case, the protective hardware failed or was unable to sense the presence of the arcing fault. Excessive current eventually causes the windings on the substation's power transformer to overheat, severely cooking its innards and raising the flammable mineral oil within to the boiling point. In a vain attempt to prevent the transformer's tank from exploding, pressure release valves or a failing tank gasket vents steam-like clouds of superheated oil vapor. The foggy mist of hot oil is then ignited by the arc, causing it to explode in a ball of flame. This is quickly followed by a phase-to-phase short on the HV side, perhaps caused by a flashover within the flames or by a heat induced fault within the transformer . The phase-to-phase short causes an upstream circuit breaker (in another substation) to blow, finally killing power to this substation. However, by this time, the overheated transformer's tank fails, and it dumps hundreds of gallons of flaming mineral oil onto the already devastated substation. Local firefighters can only watch from a distance since there's no way to safely fight this fire. The substation is a total loss. As linemen often say, "Firemen don't mess with their wires, and linemen don't mess with their fires".  A very sobering look at the explosive power lurking within that quietly humming substation in your neighborhood... NOTE: Based on recent inputs from employees of Florida Power and Light, this event occurred at the Ives Dairy Substation located near San Simeon Way and Biscayne Boulevard in Miami, Florida. It is believed to have occurred in 2000 or 2001, and the footage was captured by a local resident from his home which was adjacent to the country club and golf course. The root cause was a defective fuse holder associated with motor-operated high voltage switches. Substation switchgear was disabled when a small fuse blew, opening control power for the substation's protection hardware. Normally, the blown fuse would trigger an alarm to the dispatcher so that the problem could be promptly fixed by maintenance personnel. However, in this case, the defective fuse holder also prevented the alarm from being sent, so the power company was unaware that the substation had become completely unprotected. Some time later, a low voltage side capacitor bank failed, creating an arcing fault that could no longer be cleared, since the substation's protection hardware was inoperable. The arcing fault ultimately led to the total destruction of the substation. Although at least one report indicated that the spray of white mist might have been water from a fire suppression system, it is now known that this particular substation did not employ an active fire suppression system. The spray was, in fact,  a "fog" of overheated, vaporized mineral oil, and the explosion was quite likely an example of a dangerous BLEVE (Boiling Liquid Expanding Vapor Explosion). If you can provide any more information about this event, please contact me.

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480 volt 3-phase Arc Flash Demonstration

Click on image for a 30 second 4 MB clip

An electrical explosion, or "arc flash", occurs when one or more high current arcs are created between energized electrical conductors or between an energized conductor and neutral ground.  Once initiated, the resulting arc(s) can bridge significant distances even though the voltage is relatively low. In the above demonstration, arcs were intentionally initiated by bridging #28 AWG wires across three 1 inch copper bus bars in a testing laboratory. When power is applied, the wires immediately explode, forming a conductive plasma which creates high current power arcs between the bus bars.  In the above example, three one inch copper bus bars were separated by one inch, and were connected to a 480 volt open circuit source (a delta-connected distribution transformer). During the 842 millisecond event, the average short circuit current was 17 kiloamperes, and the peak current exceeded 30 kiloamperes. The energy dissipated within a power arc is limited only by the fault current capability of the upstream power source and the duration before protective hardware will "clear" (interrupt) the short circuit. In many low voltage (480 - 600 volt) electrical power distribution systems, fault currents can exceed 70,000 amps. The thermal energy liberated within a high current arc can be many tens of megawatts, and the arc core may reach 35,000 degrees F (four times that of the surface of the sun!). As the arc "roots" vaporize portions of the copper bus bars, the vapor explosively expands to over 60,000 times its solid volume. It then combines with oxygen in the atmosphere, forming dense clouds of cupric oxide, blackening the air and covering nearby objects with black "soot". Globules of molten copper are also violently ejected, showering the immediate vicinity with 2,000 degree droplets that can approach speeds of 700 miles per hour. Magnetic forces propel the arc along the bus, extending it in the process, and magnetic forces on the bus  bars and cables may be sufficient to bend bus bars and rip them from their mountings, sometimes creating additional shrapnel.  An unprotected individual unlucky enough to be anywhere near this event would be seriously injured or killed. Because of the extreme danger,  most countries now require electrical workers to wear protective clothing and headgear whenever working near energized high energy equipment. Some additional video clips, demonstrating the effects of 480 volt industrial arc flashes, and their effects on manikins clothed in regular (unprotective) and protective clothing can be seen on the Westex site.

High Voltage Fuse Fails in a Substation, Continues Arcing...

Click on image for a 35 second 10 MB avi clip

The above incident was captured on October 30, 2005 at a Pacific Power substation in Corvallis, Oregon by nearby Oregon State University students. An overload on one of the phases apparently initially caused a HV fuse to open too slowly. High voltage fuses are normally designed to open quickly, either by rapidly generating large volumes of internal gas to explosively "blow out" the arc (as in an expulsion fuse),  or to vaporize a silver wire within quartz sand, creating a high resistance "fulgurite" that quietly opens the circuit (as in a Current Limiting Fuse or CLF). In the case of this particular fault, a HV fuse opened but it failed to quench the arc, causing the circuit to remain energized through the resulting arc path. Although in the clip the arc is initially only passing load current, the arc eventually chews up the fuse body. The arc then jumps to other portions of the fuse holder or to the grounded substation support structure where it can inflict significant damage. As can be seen in the clip, the arcing ended up raining a bit of molten metal down to the substation floor before power was finally cut. Used with permission by Douglas Van Bossuyt, douglas.vanbossuyt@gmail.com

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Crane Tangles with a 46 kV Feeder... and Loses!

The above sequence of jpegs show what happens when the boom of a Link Belt crane accidentally comes too close to a 46 kV power feeder. The HV feeder arcs to the boom, elevating the potential of the entire crane to 46 kV. The base of the crane then arcs to the steel reinforcement bars in the concrete, vaporizing moisture in the concrete below the crane, causing it to explode! After a couple of reclosures, the feeder's cut-out (circuit breaker) finally locks out, killing power to the feeder. However, by this time the crane's hydraulic oil, hoses, and tires have all ignited, and the crane becomes a total loss, as it becomes fully engulfed in flames. Fortunately, the crane's operator escapes with only minor injuries.

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Huge positive lightning bolt almost zaps an Australian lightning photographer

(Click on image for larger view (199 kB))

Photo courtesy of Kane Quinnell

The above photo is courtesy of Kane Quinnell from Australia. It was almost his last. The above lightning stroke was almost certainly a "bolt from the blue" - a relatively rare positive lightning bolt that originates from the top region of a storm cloud rather than from the negatively charged cloud base. These massive discharges can travel horizontally, often in the clear air away from the storm, for up to 35 miles from the top of the main storm. Positive lightning bolts can pack peak currents of up to 340,000 amperes, and they usually have a long lasting "tail" of current that persists for hundreds of milliseconds. This is about ten  times more current and ten times longer than regular (negative) lightning. As a result, positive lightning is extremely hot, and it does considerable damage to whatever it hits. If you happen to be unlucky enough to be the target of one of these monster bolts, you DO NOT survive. If you look at the above image very carefully, you can see a small leader coming up from the top of the shed, just to the right of the main stroke. Here's some additional information about "Bolts from the Blue", and following is Kane's description of what happened in his own words: "I happened to be out in the back yard, watching a storm on Friday night (14/01/05) that appeared to be a few km away, (I live in Old Toongabbie, and the storm appeared to be in Pendle Hill, or Greystanes, Australia). I set the camera's settings so that the shutter remained open for four seconds, placed it on the back bumper of my car, hoping to get a few shots of lightning in the clouds a few kilometers away. There was no rain at all, and stars could be seen over the north 1/3 of the sky, so I did not feel in danger in any way. Boy was I mistaken... DO NOT UNDERESTIMATE ELECTRICAL STORMS - YOU COULD GET YOURSELF KILLED! I clicked away a few times, and got nothing, and then clicked the button again, and within 0.5 seconds of me pressing the button, I had jumped at least 2 metres in the air, as I heard a tremendously loud crack of thunder, and see this amazingly bright beam of electricity right in front of me. I had then landed, grabbed the camera, and was inside the house within 2 seconds. I did not realize just how lucky I was until I uploaded the picture to my computer, and saw a leader stroke that must have originated no more than 2 metres from where I was standing next to my car, under my carport. Had the main charge taken the leader near me, rather than the one it did, I would be dead. When lightning strikes, it actually comes up from the ground first (called a leader stroke), this stroke makes the air within it conductive, and once it reaches the cloud, you have a complete circuit, and the bolt of lightning comes down from the cloud along the leader stroke. First leader to the cloud wins, luckily mine did not. I estimate that the main bolt was approximately 1.5- 2 metres in diameter, and struck something in the yard behind the shed that is located at the back of the yard. That would have had an extremely large charge, and would have been extremely hot, hotter than the surface of the sun, at 5,500 degrees Celsius, it could have been around 30,000 degrees Celsius. Needless to say, I was buzzing for the rest of Friday night, due to the amount of adrenaline going through me 'cause of how close it had come." Kane Quinnell was one very lucky bloke!

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NEW! Dueling Musical Tesla Coils try to "Zap" Daring Local Tesla Coiler

This was captured on September 8, 2007 in Baraboo Wisconsin at the 2007 Cheesehead Teslathon, sponsored by Resonance Research Corp. Local coiler "Dr. Zeus" (Terry Blake) challenges man-made lightning bolts from two identical high power solid state Tesla Coils. Identical Tesla coils, constructed by Chicago-area coilers Steve Ward and Jeff Larson, are being modulated via separate MIDI outputs from a laptop PC. Steve Ward's coil is on the left, and Jeff's on the right. Each coil is capable of generating sparks over 10 feet long. Dr. Zeus is wearing a custom-designed personal "Faraday Cage" that fully protects him from the high voltage current. He easily lights a string of 120 volt light bulbs from the high current coming from Steve's coil, takes simultaneous hits from both coils, and when he steps onto a 1/4" polyethylene sheet, you can see sparks jumping off his feet to ground. Stay tuned for even more incredible footage on YouTube... NOTE: This is an EXTREMELY dangerous demonstration. It requires significant high voltage experience and electrical engineering expertise. It should NOT be attempted by amateur coilers!!

 

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1.6 Million Volt miniature lightning "cloud"discharges inside a acrylic block...

(Click on image for larger view)

This is a rarely witnessed sight. A miniature "lightning bolt" is forcing its way out of a very highly charged block of acrylic. A 5 million electron volt (MeV) linear accelerator was used to force a tremendous number of high energy electrons deep inside the block. This created a highly charged cloud-like region of electrical charge, called a space charge, in the center of the block. Since acrylic is an excellent electrical insulator, the huge charge was temporarily trapped, similar to the way electrically charged regions become temporarily trapped within thunderclouds prior to a lightning strike. The electrically charged region inside this block reached an estimated potential of over 1.6 million volts prior to being discharged. We then manually created a path for this trapped charge to escape by carefully poking it with a pointed grounded conductor (as shown above). This allowed the trapped charge to overcome the electrical strength of the acrylic, creating thousands of hot, ionized (electrically conducting) paths, which permitted the trapped electrons to escape through the main "root" of the discharge. In the above picture, excess charge is actually being removed FROM the block, and not being injecting into it.  The following video clip shows a charged cube being manually discharged, followed by a series of secondary discharges. Larger specimens may sparkle and sizzle for  some time after the main discharge. As the electrons surge out of the block, they create a brilliant, high current, lightning-like discharge that lasts for only 40-80 billionths of a second (40-80 nanoseconds).  The peak current in the above discharge (taken through a neutral density filter to reduce its brilliance) is estimated at between 300 and 600 amperes. Larger specimens may have discharge currents of thousands of amperes. The energetic electrical discharge creates millions of microscopic fractures in permanent tree-like branching chains. The characteristic fractal pattern is called a Lichtenberg figure - a "Captured Lightning" sculpture. We recently added another video clip of a large 18" x 18" x 1" Lichtenberg Figure being created during our 2005 production run. (Click on image for larger view) A charged piece of acrylic behaves like a charged high voltage capacitor, and a harmless looking piece of acrylic can retain a surprising amount of energy. For example, the charged region within one of our 12"x 12" x 1" figures has an internal potential of over 2.2 million volts, and the acrylic block can store almost 1000 Joules (Watt-seconds) of electrostatic energy.  Discharging large Lichtenberg figures must be done very carefully, since the resulting high current (1,500-3,600 amp) impulse can potentially injure, or even kill, an unwary experimenter.  Because of their intricate detail and beauty, Lichtenberg figures bridge the boundary between art and science. The chains of tiny fractures behave as little mirrors, reflecting ambient light, and brightly glowing if illuminated through an edge. More information about these fascinating scientific sculptures can be found here. Stoneridge Engineering is proud to be the sole source for the world's most beautiful 2D and 3D Lichtenberg figures. See Gallery1 and Gallery2 for more eye candy. A video clip of a large (18" x 18" x 1") figure being discharged during our 2005 production run: What Happens when a LIVE High Voltage Power Line Hits the Ground? The following pictures are of an artificial fulgurite that was created when a high voltage power line fell during a windstorm, and then continued to arc to the ground for a couple of hours. When a high voltage power line initially contacts the ground, it begins arcing. The intense heat of the arc and the high current flowing into the ground cause sand, rocks, and minerals in the soil near the line to fuse into a glassy, lava-like substance. A couple of video clips showing downed power lines arcing to the ground can be seen here and here. In the latter video clip, the molten region of soil near the downed line can clearly be seen glowing for quite some time even after power was turned off. For a variety of technical reasons, downed power lines may remain energized for quite some time before the power company detects the problem and kills power to the circuit. Even worse, automatic "reclosers" may temporarily cut off power for a few seconds, and then reapply it with no warning. This sequence may repeat several times before the recloser locks out and must be manually reset. During the brief dead times, a person may think that the line is safely dead,  and get injured or killed when power is suddenly reapplied. Since molten minerals are excellent electrical conductors, the current-conducting area around the line continues to expand and glow as power continues to flow.  Once power is finally removed, the molten materials solidify into a bubbly, glassy "rock", leaving a man-made fulgurite behind. Unlike a natural fulgurite, one created by a downed power line tends to be considerably thicker and more massive. Linemen sometimes call these curious artifacts "clinkers".  As with natural fulgurites, clinkers are also hollow with polished, glassy interior walls. However, because they're thicker, they tend to be considerably heavier and massive than the thin, fragile lightning-created fulgurites which are created within a fraction of a second. These  pictures are of a clinker that was formed in Northern California in 1994 when a 7,200 volt power line fell onto a pile of clam shells next to a canal in Hickman, California.  Although this 28 inch long specimen weighs about 80 pounds, it is actually only a small piece of the 15 foot long clinker that was created. Shell fragments can be seen imbedded in the exterior of the glassy walls.  The above pictures were provided courtesy of  Scott Falke. This specimen currently resides in the Turlock (California) Irrigation District's corporate office. Physics is fun!

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Some other interesting places to visit:

Tesla Info Center	10" Tesla Coil	The "Quarter Shrinker"	Our Shrunken Coins	Our Lichtenberg figures

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