Electricity. It lets you know when it wants out

[VatorMan]

I took this drone shot of our power plant last week for our local utility. It consists of a 8 MW COGEN, 2 type D boilers, and 7 RU's.

[VatorMan]

Better view.

[Aerovette]

Originally Posted by z06psi

Someone call aero.

I already worked on it once. Can't you tell ?

[Cybercowboy]

Originally Posted by FLEXjs

Wild how they touch that rod to the power line to equalize the potential. I don't even get how that works.

Electrical engineering degree here. The way it works is amazingly simple. The helicopter is just a big chunk of metal suspended in the air. When you touch the metal cable to a high voltage line, initially there is a small amount of current that flows from the high voltage line to the helicopter, until the entire helicopter is at the same voltage potential. The charge itself just distributes itself on the outside of the air frame, and the occupants likely don't even feel a thing. Since there is no path to ground, air being a very good insulator, the power line and the helicopter and everyone touching the helicopter are now at the same potential, and someone could literally grab onto that 200 kV line (whatever it is) with their bare hand and be fine. But if they got near anything else that had a path to ground or a different phase, insta-zap death.

[mrvette]

Originally Posted by Cybercowboy

Electrical engineering degree here. The way it works is amazingly simple. The helicopter is just a big chunk of metal suspended in the air. When you touch the metal cable to a high voltage line, initially there is a small amount of current that flows from the high voltage line to the helicopter, until the entire helicopter is at the same voltage potential. The charge itself just distributes itself on the outside of the air frame, and the occupants likely don't even feel a thing. Since there is no path to ground, air being a very good insulator, the power line and the helicopter and everyone touching the helicopter are now at the same potential, and someone could literally grab onto that 200 kV line (whatever it is) with their bare hand and be fine. But if they got near anything else that had a path to ground or a different phase, insta-zap death.

What is a shock to ME is that the humidity in the air would not make for a tingling sensation to anyone in the copter......and of course if it was RAINING???

[FLEXjs]

Originally Posted by Cybercowboy

Electrical engineering degree here. The way it works is amazingly simple. The helicopter is just a big chunk of metal suspended in the air. When you touch the metal cable to a high voltage line, initially there is a small amount of current that flows from the high voltage line to the helicopter, until the entire helicopter is at the same voltage potential. The charge itself just distributes itself on the outside of the air frame, and the occupants likely don't even feel a thing. Since there is no path to ground, air being a very good insulator, the power line and the helicopter and everyone touching the helicopter are now at the same potential, and someone could literally grab onto that 200 kV line (whatever it is) with their bare hand and be fine. But if they got near anything else that had a path to ground or a different phase, insta-zap death.

Exactly how it was explained to me but I still can't get my head around it.

My thoughts are that in order for the electricity to determine there is no ground/path it still has to flow through you. So why wouldn't you feel it or get electrocuted?

[FLEXjs]

Originally Posted by mrvette

What is a shock to ME is that the humidity in the air would not make for a tingling sensation to anyone in the copter......and of course if it was RAINING???

Just as an FYI pure water does NOT conduct electricity.

Water conducts electricity only because most of it is not pure; it contains dissolved solids. When those solids are dissolved they split into positive and negative ions, and that is what allows it to conduct electricity.

[Giraffe (He/Him)]

Oh. I know one more thing. Our new generator weighed 500 ton. You should have seen the rigging on that bitch. Our Steam Generators were ‘Only’ 300 ton.

[Cybercowboy]

Originally Posted by FLEXjs

Exactly how it was explained to me but I still can't get my head around it.

My thoughts are that in order for the electricity to determine there is no ground/path it still has to flow through you. So why wouldn't you feel it or get electrocuted?

It only takes a very small amount of charge to accumulate for the potential of the line to match the potential of the helicopter/occupants. And this charge will always distribute on its most happy resting place which is the outside of a metal shell. You'll get about the same amount of charge on your body that you'd get by rubbing a balloon on your hair. And indeed, your hair would probably be sorta frizzed out as the like-charged particles (electrons in this case) that are on each hair repel one another. Like when you see people who touch Tesla coils. The potential is very high, the charge/current is very very low.

Would you feel anything in the helicopter? I'm sure you would, but it wouldn't be unpleasant, just perhaps a bit unnerving to n00bs. If you were actually inside the helicopter, you wouldn't feel anything because you are essentially inside of a Faraday cage. The net charge inside a Faraday cage is zero. All the charge is on the outside.

[Cybercowboy]

Originally Posted by mrvette

What is a shock to ME is that the humidity in the air would not make for a tingling sensation to anyone in the copter......and of course if it was RAINING???

High humidity would not be a problem. Even saturated to 100% humid air is a very good insulator. If it was raining hard enough to lower the resistance of the air, and the rain itself was dirty enough to conduct electricity well, at that point it would probably be unsafe conditions in general and they wouldn't even be flying around in a chopper around power lines period. But just a little rain would be OK, it would just make the distance you could get from a grounded object a bit farther. Like instead of being safe at 4 feet away when it's not raining, maybe you'd be safe only from 5 feet away.

[VatorMan]

We have Corona (not virus) detection in our 15KV substation. I'm OK with snap,crackle,pop. I run like hell if I hear bacon frying.

[Bill]

Originally Posted by Cybercowboy

High humidity would not be a problem. Even saturated to 100% humid air is a very good insulator. If it was raining hard enough to lower the resistance of the air, and the rain itself was dirty enough to conduct electricity well, at that point it would probably be unsafe conditions in general and they wouldn't even be flying around in a chopper around power lines period. But just a little rain would be OK, it would just make the distance you could get from a grounded object a bit farther. Like instead of being safe at 4 feet away when it's not raining, maybe you'd be safe only from 5 feet away.

We work on pipeline right of ways, so we're around high line easements fairly often, as they're often in the same easement, or they cross each other. You can get a reasonable tingle of a shock when grabbing a truck door handle or touching metal on a tractor while standing on the ground, even while wearing rubber boots, if you're around those high lines. For what it's worth, Houston is high humidity a LOT of the time, some are saying, most of the time. We've got high humidity, I can tell you that.

[Cybercowboy]

Originally Posted by bill_daniels

We work on pipeline right of ways, so we're around high line easements fairly often, as they're often in the same easement, or they cross each other. You can get a reasonable tingle of a shock when grabbing a truck door handle or touching metal on a tractor while standing on the ground, even while wearing rubber boots, if you're around those high lines. For what it's worth, Houston is high humidity a LOT of the time, some are saying, most of the time. We've got high humidity, I can tell you that.

Absolutely. That wouldn’t be the case if the lines carried DC current, but you’re well grounded and human bodies have a small capacitance which can result in what you’re describing. It’s not dangerous but definitely unnerving. AC current flowing in the lines induces current in pretty much anything nearby that is grounded, even in a vacuum.

To AC current, air/vacuum has this property. https://en.m.wikipedia.org/wiki/Vacuum_permittivity

[Aerovette]

In electrical shop in high school, we would put leads on a DC variable power supply and put one in each hand while someone cranked up the juice. We'd see how high it would get before you had to let go. Imagine your whole body feeling like hitting your funny bone in your elbow. You body feels like a giant vibrator.

[Entropy]

Originally Posted by FLEXjs

Just as an FYI pure water does NOT conduct electricity.

Water conducts electricity only because most of it is not pure; it contains dissolved solids. When those solids are dissolved they split into positive and negative ions, and that is what allows it to conduct electricity.

Yup.
It's pretty expensive to get that stuff out of water, and even then, there's always ions in water due to auto ionization.

One of the ways we measure water purity is with resistance. The system I use will purify water up to 18 MΩ.

[mrvette]

Originally Posted by Entropy

Yup.
It's pretty expensive to get that stuff out of water, and even then, there's always ions in water due to auto ionization.

One of the ways we measure water purity is with resistance. The system I use will purify water up to 18 MΩ.

I assume the water is in a glass container when measured, but how far apart are the electrodes used for measuring?? and how large are they??

[JetMechZ16]

[JetMechZ16]

We have some of these at work. I'm sure you guys know more about them than I do.

[FLEXjs]

Originally Posted by Entropy

Yup.
It's pretty expensive to get that stuff out of water, and even then, there's always ions in water due to auto ionization.

One of the ways we measure water purity is with resistance. The system I use will purify water up to 18 MΩ.

I used to work for a company that sold Reverse Osmosis water purifiers (have one in my kitchen) and we had a contraption to show the before and after RO purification process where we had a light bulb hooked up to a plexiglass tub with electrodes at the end. With regular tap water the bulb would light up. With RO water it wouldn't.

The sales guys would even stick their hands in the RO water with the current on.

[Aerovette]

Originally Posted by Entropy

Yup.
It's pretty expensive to get that stuff out of water, and even then, there's always ions in water due to auto ionization.

One of the ways we measure water purity is with resistance. The system I use will purify water up to 18 MΩ.

Dorked this up. Sorry.