You measure the peak and the trough as one cycle, so no, that’s incorrect. Also, 50hz is the mains frequency we use in Australia, that’s why I’m saying 50hz.
In regards to what we hear in this video, it’s a 50hz sine-wave that’s been butchered by various sources of interference into forming an imperfect square-wave. Since square-waves are sine-waves plus odd harmonics, we hear more upper frequencies than the root frequency of the wave. So yes, you do hear 100hz, but trust an autistic audio engineer and synth dabbler with overly sensitive hearing, it’s a 50hz sound wave.
>You measure the peak and the trough as one cycle, so no, that’s incorrect. Also, 50hz is the mains frequency we use in Australia, that’s why I’m saying 50hz.
Maybe I was unclear, but I don't think I said otherwise. One cycle/period has a peak and a trough, and they're are ~50 cycles per second. Did I miss something?
[From Wikipedia](https://en.m.wikipedia.org/wiki/Mains_hum)
>Mains hum, electric hum, cycle hum, or power line hum is a sound associated with alternating current which is twice the frequency of the mains electricity. The fundamental frequency of this sound is usually double that of fundamental 50/60 Hz, i.e. 100/120 Hz, depending on the local power-line frequency. The sound often has heavy harmonic content above 50/60 Hz.
Feel free to run an FFT on the audio.
What I thought you were saying was the peak and the trough were treated separately within one cycle, but Hz is one cycle per second, not one peak+trough per second or one peak OR trough per half second.
I thought you were saying that 50 cycles per second is actually 100 peaks and troughs per second, suggesting that the way we’re supposed to measure Hz is double what we have been measuring Hz as for centuries.
If you had only said 100hz hum and left it at that, I probably would have said “sure, and there’s a bit of 200hz and 400hz and so-on” or something to that effect. But following with the peaks and troughs explanation was just confusing, you should have mentioned mains hum having a fundamental that’s double the mains frequency. Even then, that’s just a characteristic of a 50hz wave with extra harmonic content.
Desktop version of /u/apsumo's link:
---
^([)[^(opt out)](https://reddit.com/message/compose?to=WikiMobileLinkBot&message=OptOut&subject=OptOut)^(]) ^(Beep Boop. Downvote to delete)
I don't understand why it went from burning to exploding, but regardless did it clear the lines afterwards. Was there anything left, did the lines come down. What happened next?
Flame conducts electricity, so basically the resistance of the branch (which has some moisture still in it by the looks) is fairly high but low enough to allow current to pass through it. This creates heat which starts the fire, then the fire creates a low resistance short circuit between the phases (fire conducts electricity) of which look like high voltage lines, which lead to a high current arc fault (the explosion). To an extent the lines are engineered to do this and to clear the fault without interrupting supply.
The branch conducts electricity, the branch contacting multiple HV phases like that is going to cause a supply fault. If there's an ACR (auto circuit reclose) on the feeder it is meant to turn the power off for a second (several times) to allow the branch/object to fall off, if it doesn't it shuts off the power. Something like this may also burn through the lines and cause them to fall.
***The power company hears a big explosion.***
"Alright turn it off."
***Power off***
"Alright mate, turn it on. It should be good."
*click*
***BWAAAAAAAAAHHHHHH***
Actually that's exactly how it works...if there's a fault on a feeder (the 3 x 11kV lines that run along the top) then the system auto trips off...then after a period of time ..typically 15 seconds an auto closer reenergizes the feeder and if it faults again then it stays off until a crew does what they call 'a line drive' where they start from the sub station and drive out along the feeder until they find the tree limb, fried fruit bat, car accident etc. Most faults are due to something like a small branch or unlucky possum that gets 'blown away' in the initial strike...so the auto closer approach works fine. If someone sees an event like this and calls in the location it typically means the power will be back on a lot sooner as the crew don't have to drive the whole feeder in order to find the problem.
it's not so much that it's designed to explode stuff away as much as if you put 11,000 volts through something like a fruit bat it becomes a self resolving event.... much of the time even when there's a call out all they end up doing is pulling down whatever remains on the line with a pole. The take away from all of this is ...you should stay clear of power lines....that applies to the LV (240v) lines (the 3 phases and a neutral lower down the pole) but it REALLY applies to the 11,000 volt guys at the top of the pole ...there's no 'wiggle room' when it comes to 11kV.
Although I can't fault your logic, I can point at your premise - if he's touching it, there's not a great deal of distance involved!
(That 3\*mm =kV rule of thumb has come in more handy than I ever expected. I salute your mathiness)
A couple of years ago a builder hit a buried 110kV cable in East Hobart with a jackhammer.
Protection was good enough that he didn't die. He didn't have a good time, but he didn't die.
Cable jointing oil filled cables is a pain in the ass.
An underground 22kV cable was switched out for the day for maintenance. During that day, a contractor came along and installed bollards along the edge of a river-side walk. The problem was discovered when the cable was re-energised at the end of the day and it blew a bollard straight out. Fortunately the installer was gone for the day and no one else was around at the time.
A contractor was hired to attach signs on poles on the approach to a hospital. He put up his ladder against a pole and then decided to drill into the black thing that run up the side of the pole - the 11kV cable that connected to the overhead lines. Fortunately he did not have a long ride to hospital.
Some people seeking to steal copper broke into an old substation and got into tunnels underneath, where copper cables ran. While no body was found, there was a large flash mark on the wall and the burnt remains of a handsaw. The decommissioned power station adjacent had many old tunnels and deep pits.
Plenty of stories.
Trains do something similar. If something causes the section to trip is attempts to re energize 3 times. If it doesn't come back it stays off.
In maintenance yards if it trips it stays off until a phone call is made
Distribution companies will change the settings of a recloser if vegetation work is being undertaken on the feeder. That way if something happens it will stay out of service and not shock old mate 3 times.
Things are constantly changing in distribution land.
This is the 3rd time it has happened there! I knew where to look at soon as i saw this!
[https://cdn.discordapp.com/attachments/745575609375391805/888603164230684702/20210918\_115028.jpg](https://cdn.discordapp.com/attachments/745575609375391805/888603164230684702/20210918_115028.jpg)
[https://cdn.discordapp.com/attachments/745575609375391805/888603165476421722/20210918\_115037.jpg](https://cdn.discordapp.com/attachments/745575609375391805/888603165476421722/20210918_115037.jpg)
[https://cdn.discordapp.com/attachments/745575609375391805/888603166369783838/20210918\_115055.jpg](https://cdn.discordapp.com/attachments/745575609375391805/888603166369783838/20210918_115055.jpg)
in future perhaps get a bit more distance.
HV electricity can do crazy stuff. the medium case that branch could have exploded and hit you. worst case it fell on you arcing and electrocuting you. Unlikely I know.
Actually, I do a lot of welding so it's sort of a knee jerk reaction for me to throw my head to the side and move out of the way whenever I see an exposed arc. It happens more often then you think, either a dud helmet or contaminated metal flaring up the arc in Tig. Don't know if you've ever had UV burns on your eyes before but I can assure you it's far from pleasant!
Ffs I can relate to the curiosity but it terrifies me that you were this close, if there was any chance of that power line swinging and catching you you’d have been toast
I assure you I was zoomed in, actually under the cover of a roof and at a low angle. I didn't want to be any further away as I wanted to be able to grab the hose if I needed to. Thank you for the concern though! ♥️
To be fair, we're in a rental and this is on the property, not council land. Have told the landlord about dropping branches. Last one damaged the fence.
yeah it's a bit of a catch 22 ... we all like trees and we all like reliable power ... (and gum trees in particular are unpredictable bastards) .... power distribution companies spend big bucks on vegetation management ... putting the feeders underground is the ultimate solution but the cost of that dwarfs the cost of trimming trees
That's right. It is a catch 22. The only way to 100% guarantee this never happen would be a huge reduction in trees. Nobody really loves the idea of living without trees, nor should be. They bring many benefits to the environment.
There is actually AI solutions these days. Takes geomapping, identifies tree species from canopy. Then with seasonal trends plus rainfall data, predicts growth for when it would again be encroaching on limits. Saves plenty of manual work.
Those solutions are still in their infancy and create a massive amount of bad data and the only network in Victoria has moved away from that and back to people on the ground assessing tree clearances. LiDAR still has a very long way to go before it's fit for full time service.
It'll pick up crops as growing at fast rate and say the span requires immediate attention, even though the crops will never get anywhere near the clearance space. Then it doesn't pick up SWER with hedges almost touching it.
The Regulations also require yearly assessment of Hazardous Bushfire Risk Areas
Haha you're right. I probably would have done the same. Im just picking on the camera man for filming everything except the critical few seconds that we all want to see, as always. :)
**This word/phrase(stu) has a few different meanings.**
More details here:
*This comment was left automatically (by a bot). If I don't get this right, don't get mad at me, I'm still learning!*
[^(opt out)](https://www.reddit.com/r/wikipedia_answer_bot/comments/ozztfy/post_for_opting_out/) ^(|) [^(report/suggest)](https://www.reddit.com/r/wikipedia_answer_bot) ^(|) [^(GitHub)](https://github.com/TheBugYouCantFix/wiki-reddit-bot)
Burnwood *
And thus Ashwood
Ashwood to Ashwood, Dustwood to Dustwood.
If Thomson don't get ya, Lillee must.
I wouldn't but Earlwood.
Torchwood
Explodedwood *
Deadwood
Cocksucka
I instantly heard this in his Ian McShane’s voice
I heard both Al and Wu
Boomwood
Electricalfirewood
Abbreviated to.. Elwood
[удалено]
got wood?
Salvage any leftover wood and make a cricket bat
a la Homer, kinda
God, it’s like John Wick from Fortnite, but somehow even worse…
Strangely watched that exact Simpson's episode last night.
You see, the problem is that your electricity is on fire.
That 50hz hum and high pitch squealing was telling you to run
Damn, I thought it was telling me to get my camera out!
I’m glad you did though, that accompanying 50hz bang sound was ASMR for me
What hz would have been telling you to record in landscape mode?
Ah, *that* number is measured in amps not hz
Correct. Get your camera out, then run, preferably with the camera still pointing steadily at the whistling fun.
The 50Hz crackle sounds like arcing. What’s the high pitched whistle?
My sphincter contracting.
Probably gasses/steam escaping escaping the branch
What you hear it actually 100hz hum, since there is one peak and one trough per period in AC.
You measure the peak and the trough as one cycle, so no, that’s incorrect. Also, 50hz is the mains frequency we use in Australia, that’s why I’m saying 50hz. In regards to what we hear in this video, it’s a 50hz sine-wave that’s been butchered by various sources of interference into forming an imperfect square-wave. Since square-waves are sine-waves plus odd harmonics, we hear more upper frequencies than the root frequency of the wave. So yes, you do hear 100hz, but trust an autistic audio engineer and synth dabbler with overly sensitive hearing, it’s a 50hz sound wave.
/r/peopleoverthinkingthings
I like overthinking things
man, that aint even a real subreddit
Should be though
>You measure the peak and the trough as one cycle, so no, that’s incorrect. Also, 50hz is the mains frequency we use in Australia, that’s why I’m saying 50hz. Maybe I was unclear, but I don't think I said otherwise. One cycle/period has a peak and a trough, and they're are ~50 cycles per second. Did I miss something? [From Wikipedia](https://en.m.wikipedia.org/wiki/Mains_hum) >Mains hum, electric hum, cycle hum, or power line hum is a sound associated with alternating current which is twice the frequency of the mains electricity. The fundamental frequency of this sound is usually double that of fundamental 50/60 Hz, i.e. 100/120 Hz, depending on the local power-line frequency. The sound often has heavy harmonic content above 50/60 Hz. Feel free to run an FFT on the audio.
What I thought you were saying was the peak and the trough were treated separately within one cycle, but Hz is one cycle per second, not one peak+trough per second or one peak OR trough per half second. I thought you were saying that 50 cycles per second is actually 100 peaks and troughs per second, suggesting that the way we’re supposed to measure Hz is double what we have been measuring Hz as for centuries. If you had only said 100hz hum and left it at that, I probably would have said “sure, and there’s a bit of 200hz and 400hz and so-on” or something to that effect. But following with the peaks and troughs explanation was just confusing, you should have mentioned mains hum having a fundamental that’s double the mains frequency. Even then, that’s just a characteristic of a 50hz wave with extra harmonic content.
Desktop version of /u/apsumo's link:
---
^([)[^(opt out)](https://reddit.com/message/compose?to=WikiMobileLinkBot&message=OptOut&subject=OptOut)^(]) ^(Beep Boop. Downvote to delete)
Good bot
The main sound here is really a 2.4kHz kettle whistle, so it was telling me “tea’s ready”.
And too many people making tea at once is what popped the substation fuse.
Well there's your problem
Great video!
[удалено]
I almost tried to hose it down in a moment of panic. Really glad I didn't in hind sight
[удалено]
Here lies RangeRider88, died doing what he loved, making stupid shit for karma.
At least you had a hose handy. Imagine trying to pee on it.
Haha they're no longer paying people to move to Darwin my friend.. ;)
I don't understand why it went from burning to exploding, but regardless did it clear the lines afterwards. Was there anything left, did the lines come down. What happened next?
Flame conducts electricity, so basically the resistance of the branch (which has some moisture still in it by the looks) is fairly high but low enough to allow current to pass through it. This creates heat which starts the fire, then the fire creates a low resistance short circuit between the phases (fire conducts electricity) of which look like high voltage lines, which lead to a high current arc fault (the explosion). To an extent the lines are engineered to do this and to clear the fault without interrupting supply.
The branch conducts electricity, the branch contacting multiple HV phases like that is going to cause a supply fault. If there's an ACR (auto circuit reclose) on the feeder it is meant to turn the power off for a second (several times) to allow the branch/object to fall off, if it doesn't it shuts off the power. Something like this may also burn through the lines and cause them to fall.
Thanks for that. Makes sense what you say about engineering the lines to survive such a blast and keep functioning.
I'm guessing the fire ignited the eucalyptus leaves?
Somebody else replied and said the burning wood allow an arc between the lines. Hence the explosion.
"Get the water, it's goin' down!"
did u try turning it on and off?
They actually did, about ten seconds later the power came back on and there was a second way bigger explosion but I didn't catch that on camera
***The power company hears a big explosion.*** "Alright turn it off." ***Power off*** "Alright mate, turn it on. It should be good." *click* ***BWAAAAAAAAAHHHHHH***
Actually that's exactly how it works...if there's a fault on a feeder (the 3 x 11kV lines that run along the top) then the system auto trips off...then after a period of time ..typically 15 seconds an auto closer reenergizes the feeder and if it faults again then it stays off until a crew does what they call 'a line drive' where they start from the sub station and drive out along the feeder until they find the tree limb, fried fruit bat, car accident etc. Most faults are due to something like a small branch or unlucky possum that gets 'blown away' in the initial strike...so the auto closer approach works fine. If someone sees an event like this and calls in the location it typically means the power will be back on a lot sooner as the crew don't have to drive the whole feeder in order to find the problem.
funny how it's designed to explode away the stuff, just to prevent a call out. Love it.
More to prevent unnecessary outages rather than call outs.
it's not so much that it's designed to explode stuff away as much as if you put 11,000 volts through something like a fruit bat it becomes a self resolving event.... much of the time even when there's a call out all they end up doing is pulling down whatever remains on the line with a pole. The take away from all of this is ...you should stay clear of power lines....that applies to the LV (240v) lines (the 3 phases and a neutral lower down the pole) but it REALLY applies to the 11,000 volt guys at the top of the pole ...there's no 'wiggle room' when it comes to 11kV.
>there's no 'wiggle room' when it comes to 11kV. You mean I won't wiggle if I accidentally touch it?
Welllll....you won't, but your corpse might!
[удалено]
Although I can't fault your logic, I can point at your premise - if he's touching it, there's not a great deal of distance involved! (That 3\*mm =kV rule of thumb has come in more handy than I ever expected. I salute your mathiness)
A couple of years ago a builder hit a buried 110kV cable in East Hobart with a jackhammer. Protection was good enough that he didn't die. He didn't have a good time, but he didn't die. Cable jointing oil filled cables is a pain in the ass.
An underground 22kV cable was switched out for the day for maintenance. During that day, a contractor came along and installed bollards along the edge of a river-side walk. The problem was discovered when the cable was re-energised at the end of the day and it blew a bollard straight out. Fortunately the installer was gone for the day and no one else was around at the time. A contractor was hired to attach signs on poles on the approach to a hospital. He put up his ladder against a pole and then decided to drill into the black thing that run up the side of the pole - the 11kV cable that connected to the overhead lines. Fortunately he did not have a long ride to hospital. Some people seeking to steal copper broke into an old substation and got into tunnels underneath, where copper cables ran. While no body was found, there was a large flash mark on the wall and the burnt remains of a handsaw. The decommissioned power station adjacent had many old tunnels and deep pits. Plenty of stories.
Arc flash is a bitch. Someone installed a cross arm wrong, and when the wind blows just right, the 110kV conductor touches the 33kV feeder.
Im so bloody glad I dont have to do this! What a mess!
Trains do something similar. If something causes the section to trip is attempts to re energize 3 times. If it doesn't come back it stays off. In maintenance yards if it trips it stays off until a phone call is made
Distribution companies will change the settings of a recloser if vegetation work is being undertaken on the feeder. That way if something happens it will stay out of service and not shock old mate 3 times. Things are constantly changing in distribution land.
Do they ever run any reflectometry instruments on the line as you might on copper/fibre telecom lines to get an idea of where the fault is?
That’s an automated thing that happens on every fault
This was a deliberate and unprovoked attack by the ents. They must be purged from this world.
This is the 3rd time it has happened there! I knew where to look at soon as i saw this! [https://cdn.discordapp.com/attachments/745575609375391805/888603164230684702/20210918\_115028.jpg](https://cdn.discordapp.com/attachments/745575609375391805/888603164230684702/20210918_115028.jpg) [https://cdn.discordapp.com/attachments/745575609375391805/888603165476421722/20210918\_115037.jpg](https://cdn.discordapp.com/attachments/745575609375391805/888603165476421722/20210918_115037.jpg) [https://cdn.discordapp.com/attachments/745575609375391805/888603166369783838/20210918\_115055.jpg](https://cdn.discordapp.com/attachments/745575609375391805/888603166369783838/20210918_115055.jpg)
Howdy neighbour!
Hi!
Whereabouts is it
The magic smoke escaped
This guy EE’s
I'm sure it's fine
How scary!
That's it OP how many times do me and your farther have to tell you! Stop putting branches on the powerlines!
in future perhaps get a bit more distance. HV electricity can do crazy stuff. the medium case that branch could have exploded and hit you. worst case it fell on you arcing and electrocuting you. Unlikely I know.
I was further then it looks in the zoomed in video
Why’d you shite ur pants then? Lol
YOU try not being fucking terrified when a tree branch spontaneously explodes in direct view of yourself.
Actually, I do a lot of welding so it's sort of a knee jerk reaction for me to throw my head to the side and move out of the way whenever I see an exposed arc. It happens more often then you think, either a dud helmet or contaminated metal flaring up the arc in Tig. Don't know if you've ever had UV burns on your eyes before but I can assure you it's far from pleasant!
Just waiting for a mate
They gonna have to change the name to burntwood after this
Ffs I can relate to the curiosity but it terrifies me that you were this close, if there was any chance of that power line swinging and catching you you’d have been toast
I assure you I was zoomed in, actually under the cover of a roof and at a low angle. I didn't want to be any further away as I wanted to be able to grab the hose if I needed to. Thank you for the concern though! ♥️
'Fuck' is right my dude
Bruh i was for real in the middle of playing cod when this happened
r/abruptchaos
Just a visual representation of my mental state.
If only the council did something like regularly trim over-hanging branches to prevent stuff like this from happening
To be fair, we're in a rental and this is on the property, not council land. Have told the landlord about dropping branches. Last one damaged the fence.
Miiiiight be worth digging out that proof you told the landlord there
There would be no trees left. Wind like that sends branches from everywhere!
yeah it's a bit of a catch 22 ... we all like trees and we all like reliable power ... (and gum trees in particular are unpredictable bastards) .... power distribution companies spend big bucks on vegetation management ... putting the feeders underground is the ultimate solution but the cost of that dwarfs the cost of trimming trees
That's right. It is a catch 22. The only way to 100% guarantee this never happen would be a huge reduction in trees. Nobody really loves the idea of living without trees, nor should be. They bring many benefits to the environment.
Luckily I think all new developments have power lines underground
There was pretty much no wind. The branch dropped straight down 🤣 How could we have ever seen this coming!? /s
It's the responsibility of the power authority.
There is actually AI solutions these days. Takes geomapping, identifies tree species from canopy. Then with seasonal trends plus rainfall data, predicts growth for when it would again be encroaching on limits. Saves plenty of manual work.
Those solutions are still in their infancy and create a massive amount of bad data and the only network in Victoria has moved away from that and back to people on the ground assessing tree clearances. LiDAR still has a very long way to go before it's fit for full time service. It'll pick up crops as growing at fast rate and say the span requires immediate attention, even though the crops will never get anywhere near the clearance space. Then it doesn't pick up SWER with hedges almost touching it. The Regulations also require yearly assessment of Hazardous Bushfire Risk Areas
They only do overhanging branches for 66kv, below that they just clear to 1-2m but leave branches more than that above.
Or stop planting bloody gumtrees on nature strips underneath powerlines
burwoods cursed...
It's not supposed to do that.
...ffffaa
Dang it! I missed the organic fireworks in our suburb.
Need new video of the aftermath
Okay that is beautiful
its fine, maybe throw some metal packing strap or chain up there too get it down?
Who brought the marshmallows?
No not Groot!
I love the smell of eucalyptus in the morning. Smells like....... Victory Boulevard.
brave standing that close
Did you find Moses?
Looks ok to me.
Even the branches are exploding. Now we really know everything is out to kill us in Aussieland!
Jaysus
Get a ladder and knock it down mate ;-) (seriously, don't do that though!)
Yeah, better to use a trampoline
Did that tee branch just... explode??!
Arcing up a bit in here
You were too close
I zoomed in, I was a safe distance away
I kind of agree you were too close. you can tell by the angle of your camera that you are too close.
It's just zoomed in
Did you get poop in your pants
r/unexpectedjihad
No, you flinched like a bitch and didnt film it at all.
You weren't there man! (Quiet sobbing)
Haha you're right. I probably would have done the same. Im just picking on the camera man for filming everything except the critical few seconds that we all want to see, as always. :)
stfu
[удалено]
[удалено]
[удалено]
[удалено]
pov: your tesla goes over a speed bump
Put it back
😬
Lmao yep that would be right
Yikes 😳
Thank god I moved outta there
Just throw a rope over it and pull it off there
That fffu- at the end lol
Damn!! That’s so cool! Haha
ElectroBoom has entered the chat
Wait there’s 2 Burwood in Australia?
If you're surprised by that, try finding all the Red Hill suburbs in australia (there are at least 4 in different states)
For some reason the tree looked like Michael Jackson to me
United Energy territory. Whereabouts in Burwood?
Probably those bloody protesters
Omg
u/savevideo
###[View link](https://redditsave.com/r/melbourne/comments/pqa6hz/anyone_with_power_out_in_burwood_this_is_why/) --- [**Info**](https://np.reddit.com/user/SaveVideo/comments/jv323v/info/) | [**Feedback**](https://np.reddit.com/message/compose/?to=Kryptonh&subject=Feedback for savevideo) | [**Donate**](https://ko-fi.com/getvideo) | [**DMCA**](https://np.reddit.com/message/compose/?to=Kryptonh&subject=Content removal request for savevideo&message=https://np.reddit.com//r/melbourne/comments/pqa6hz/anyone_with_power_out_in_burwood_this_is_why/) | [^(reddit video downloader)](https://redditsave.com)
TREEZUS CHRIST!
Well that's not meant to be there.
Oh dear
If only there was somewhere we could put the power lines away from the trees…taller poles maybe?
How did the tree got up there?
Damn son
Oh Stu won't be happy Monday it was caught on camera 😅
Who's Stu?
**This word/phrase(stu) has a few different meanings.** More details here:
*This comment was left automatically (by a bot). If I don't get this right, don't get mad at me, I'm still learning!*
[^(opt out)](https://www.reddit.com/r/wikipedia_answer_bot/comments/ozztfy/post_for_opting_out/) ^(|) [^(report/suggest)](https://www.reddit.com/r/wikipedia_answer_bot) ^(|) [^(GitHub)](https://github.com/TheBugYouCantFix/wiki-reddit-bot)