Electrical Wire Tears Apart Tree
- Thread starter TMW
- Start date
- Location
- North of Boston
It took 4 minutes of arcing and a phase to phase for the recloser to trip!?!
- Location
- That place north of America
Notice the height of the wires using the transformer pole as a reference? Those wires were probably 44 kv which is a delta system and delta has no reference to ground. Makes tripping a lot harder to do.
If you ever work around delta beware as there is no neutral wire and there is usually a high amperage in the system. Tripping one phase does not guarantee that the system trips out. Trees can bridge phase to phase and will sit there and burn.
If you ever work around delta beware as there is no neutral wire and there is usually a high amperage in the system. Tripping one phase does not guarantee that the system trips out. Trees can bridge phase to phase and will sit there and burn.
- Location
- North of Boston
[ QUOTE ]
Notice the height of the wires using the transformer pole as a reference? Those wires were probably 44 kv which is a delta system and delta has no reference to ground. Makes tripping a lot harder to do.
If you ever work around delta beware as there is no neutral wire and there is usually a high amperage in the system. Tripping one phase does not guarantee that the system trips out. Trees can bridge phase to phase and will sit there and burn.
[/ QUOTE ]
Curious as to why 44K is delta? Are you saying that because of how long it took to trip out?
Notice the height of the wires using the transformer pole as a reference? Those wires were probably 44 kv which is a delta system and delta has no reference to ground. Makes tripping a lot harder to do.
If you ever work around delta beware as there is no neutral wire and there is usually a high amperage in the system. Tripping one phase does not guarantee that the system trips out. Trees can bridge phase to phase and will sit there and burn.
[/ QUOTE ]
Curious as to why 44K is delta? Are you saying that because of how long it took to trip out?
- Location
- Longmont, CO
Didn't we already see this?
- Location
- That place north of America
Delta is a better transmitter of power when dealing in large capacities of electricity. On distribution, a wye system is preferred because there is a system neutral which makes it safer for line personnel. Delta was the choice in earlier times but power demand and quality of power make wye a better way to go.
I ask a lineman before why delta was so dangerous in distribution, his reply was that "even though you pulled one switch on a transformer it was still hot on both sides of the cutout". Delta requires two hot phases in one transformer to work. He also said because there is no system neutral you have to ground at the transformer. A poor ground system can lead to voltage issues for the customer.
I'm not an expert of the stuff but from what I've heard from linemen...Delta sucks.
I ask a lineman before why delta was so dangerous in distribution, his reply was that "even though you pulled one switch on a transformer it was still hot on both sides of the cutout". Delta requires two hot phases in one transformer to work. He also said because there is no system neutral you have to ground at the transformer. A poor ground system can lead to voltage issues for the customer.
I'm not an expert of the stuff but from what I've heard from linemen...Delta sucks.
- Location
- Ontario, Canada
Looks like the contact is on a sub-transmission with a 3 phase primary below it. I've seen both delta and wye systems take this long and longer to trip on primary burn downs.
- Location
- That place north of America
Its really hard to tell if there is a neutral or not on that pole. Sometimes they share the same neutral as the distribution but anytime I see an insulator that large, that high on a pole it usually means sub-transmission...which is usually a delta voltage.
The highest wye voltage I've ever heard of is 27.6kv which one one lineman told me was "the most evil voltage they've ever come up with". Not only because the voltage but the amperage that it carried.
The highest wye voltage I've ever heard of is 27.6kv which one one lineman told me was "the most evil voltage they've ever come up with". Not only because the voltage but the amperage that it carried.
- Location
- That place north of America
In our system, my company has 115kv with 14.4kv underbuild on it, also 34.5kv framed for 115kv and 25 kv framed for 115kv...so never assume voltage based on configuration.
It only takes 8 milliamps to kill. Your house runs 15 amp circuits...think about it.
It only takes 8 milliamps to kill. Your house runs 15 amp circuits...think about it.
- Location
- Canada
Thanks for spelling that out BUK. I was, and still am ignorant of what it all means, BUT I do know it is unforgiving. Hence, IF you DON'T know, STAY away from it.
AND don't plant 60 ft trees under a 30' power line!!!
AND don't plant 60 ft trees under a 30' power line!!!
- Location
- North of Boston
BUK
As a background I was a linesman for 5 years, got out of it, hated unions.
That being said Delta does suck! It has a floating neutral/floating ground concept, which means it is hard to trip. Thats great for storms/trees/animal outages. bad for linesamn, safety, general public, and a dependable voltage. Most areas in the US are phasing it out. it pretty rare in these parts above 13kV.
In New England we run almsot exclusively on WYE. From 2400-150,000. I am working in a town right now, fed from a 115kV WYE, stepped down to 23.6kV stepped down again to a 5kV system. I cant tell from that grainy video if its WYE, Delta, or DC even!
As for the loads they carry, some of that 23kV are express runs from sub to sub carrying a few hundred, to a few thousand amps depending on the loads! Linesman will not throw a cutout on a loaded circuit, unless its an emergency. They prefer to kill it, place the fuses, then let SCADA close it back in.
Not saying youre wrong, just saying theres a whole world outside of Sault Ste. Marie, Ontario
Be safe!
As a background I was a linesman for 5 years, got out of it, hated unions.
That being said Delta does suck! It has a floating neutral/floating ground concept, which means it is hard to trip. Thats great for storms/trees/animal outages. bad for linesamn, safety, general public, and a dependable voltage. Most areas in the US are phasing it out. it pretty rare in these parts above 13kV.
In New England we run almsot exclusively on WYE. From 2400-150,000. I am working in a town right now, fed from a 115kV WYE, stepped down to 23.6kV stepped down again to a 5kV system. I cant tell from that grainy video if its WYE, Delta, or DC even!
As for the loads they carry, some of that 23kV are express runs from sub to sub carrying a few hundred, to a few thousand amps depending on the loads! Linesman will not throw a cutout on a loaded circuit, unless its an emergency. They prefer to kill it, place the fuses, then let SCADA close it back in.
Not saying youre wrong, just saying theres a whole world outside of Sault Ste. Marie, Ontario
Be safe!
- Location
- That place north of America
Remember what I said before...I'm not an expert on the stuff. I've seen some different voltages out there. It all depends where you live. We have a 34.5kv delta (sub-trans) that not too many utilities use in this province.
Never seen a 115kv wye but you learn something new everyday.
As for the video, you have to admit that it could be sub-trans voltage given the placement on the pole. I'm just speculating that its delta.
Later
Never seen a 115kv wye but you learn something new everyday.
As for the video, you have to admit that it could be sub-trans voltage given the placement on the pole. I'm just speculating that its delta.
Later
- Location
- North of Boston
[ QUOTE ]
Remember what I said before...I'm not an expert on the stuff. I've seen some different voltages out there. It all depends where you live. We have a 34.5kv delta (sub-trans) that not too many utilities use in this province.
Never seen a 115kv wye but you learn something new everyday.
As for the video, you have to admit that it could be sub-trans voltage given the placement on the pole. I'm just speculating that its delta.
Later
[/ QUOTE ]
I 100% agree that one if not both of those lines are sub trans. I am curious as to why it took so long for the recloser to kick on both circuits?
Remember what I said before...I'm not an expert on the stuff. I've seen some different voltages out there. It all depends where you live. We have a 34.5kv delta (sub-trans) that not too many utilities use in this province.
Never seen a 115kv wye but you learn something new everyday.
As for the video, you have to admit that it could be sub-trans voltage given the placement on the pole. I'm just speculating that its delta.
Later
[/ QUOTE ]
I 100% agree that one if not both of those lines are sub trans. I am curious as to why it took so long for the recloser to kick on both circuits?
It's kind of funny how the people filming aren't really that concerned at first but when she really starts to sing--move the car honey, where's the fire department, and so on. I would never assume voltage based on construction or height on the pole, I'm just taking a guess based on a grainy video. By the way thanks for sharing.
- Location
- Flagstaff Arizona
Seen this again at work today I believe the boss said 115kV, but I agree it does not look like that high of a voltage. Some good recloser action near the end. Here's the info from the same video on youtube:
BELLINGHAM, Wash. -- Arcing wires are being blamed for a spectacular explosion that took place in this Northern Washington city over the weekend.
Trouble began when a 60-foot poplar tree swaying into high voltage power lines Saturday afternoon. The tree branches danced closer and closer to the lines, eventually catching on fire.....
One of the posts on youtube mentions the 115kV again.... I wonder if that will be a fine from FERC/NERC and mitigation.
BELLINGHAM, Wash. -- Arcing wires are being blamed for a spectacular explosion that took place in this Northern Washington city over the weekend.
Trouble began when a 60-foot poplar tree swaying into high voltage power lines Saturday afternoon. The tree branches danced closer and closer to the lines, eventually catching on fire.....
One of the posts on youtube mentions the 115kV again.... I wonder if that will be a fine from FERC/NERC and mitigation.
- Location
- That place north of America
Lack of tree maintenance did cause the 2003 Blackout.
- Location
- Flagstaff Arizona
[ QUOTE ]
Lack of tree maintenance did cause the 2003 Blackout.
[/ QUOTE ]
That is why we're in the process of mowing everything 69kV and above, plus factoring in full wind sway at full load and high temps.
Lack of tree maintenance did cause the 2003 Blackout.
[/ QUOTE ]
That is why we're in the process of mowing everything 69kV and above, plus factoring in full wind sway at full load and high temps.
