Electricity and electric and magnetic fields (EMFs)

[Harvard]

Is the Electrical problem "Induced" or what?

Electricity and electric and magnetic fields (EMFs)

START QUOTE:
EMFs are invisible forces that surround electrical equipment, power cords, and wires that carry electricity, including outdoor power lines.

•Electric Fields: These are formed whenever a wire is plugged into an outlet, even when the appliance is not turned on. The higher the voltage, the stronger the electric field.

•Magnetic Fields: These are formed when electric current is flowing within a device or wire. The greater the current, the stronger the magnetic field.

EMFs can occur separately or together. For example, when you plug the power cord for a lamp into a wall socket, it creates an electric field along the cord. When you turn the lamp on, the flow of current through the cord creates a magnetic field. Meanwhile, the electric field is still present.
END QUOTE:

If it is induced then it is from a Magnetic Field.
If it is capacitance then it is from a Electric Field.

Your body is 1/2 of a capacitor and unless you are off the grid, it is always exposed to an Electric Field.
For example....

[Route_66_Travel]

Take a couple of fluorescent bulbs and walk under a high voltage power line and watch them glow, then put one end in the ground and watch them really light up. Get really brave and walk barefoot under the line and see your hair stand straight up Things my brother and I did when we were young and dumb. 🙂

[vermilye]

Depending on soil characteristics, it isn't unusual to run local single phase high voltage distribution (4.8KV & 12.4KV, etc) with only one wire & using the earth for the neutral/return. Looks a bit strange to see only one wire at the top of the power pole.

[Harvard]

I have often wondered about whether or not 3 phase Electric Fields would cancel out. Appears not to be the case.

3 Phase Electric Fields

[MEXICOWANDERER]

The monitoring and control rooms are basically insulated to prevent electrostatic build up. With av pacemaker today I wouldn't get within a mile of the place.

[Harvard]

Neat stuff, had no idea DC transmission has been around since the 1970s..
So I do have some knowledge of the Magnetic Field around a DC circuit.
BUT, nothing about a DC Electric Field, or so I thought....
Then Dr Google says this:
"DC Electric Field: DC Electric Fields, can be referred to as an Electrostatic Charge present on an object"
Now that I understand.

[road-runner]

I had totally forgotten about the DC intertie. There's a wikipedia article, and sure enough, it has a picture of a tower with two big insulators.
https://en.wikipedia.org/wiki/Pacific_DC_Intertie

[Harvard]

Mex!!!! Very interesting, thanks for sharing. I will be thinking about DC transmission advantages for a very long time.

[MEXICOWANDERER]

It's the Path 4, West Coast intertie line. Washington state to Reseda CA. 3.5 gigawatts capacity. Direct current system. Not A.C.

It's 1 megavolts 1,000,000 volts direct current. The 10 meter distance, length of the insulators, is a clue.

The two wires are the same polarity.

in a ditch adjacent to the towers is the negative pathway. It is filled with conductive media. I was invited to a field survey in Ely Nevada that discussed basic soil composition and conductance to minimize earth eddy currents. Eastern Nevada was chosen over the alternatives because of that reason. I was a guest of Siemens.

Software controlled conversion and reversion of DC. Components are giga size with appropriate cooling air temperatures, moisture and contaminate containment.

An interesting study. The science behind it is in another dimension. This is PhD territory beyond my capabilities when I attended and now outside my area of interest. Power generation and storage is quite enough for me these days 🙂

Software controlled rectification using ultra low forward voltage drop interests me. As does artificial EMP and solar EMP. If alternator rectification involved .002 vf you cannot imagine the advantages. And it implies direct interface with camping and RV'ing. 🙂

[Harvard]

"In the last diagram, which wire is a neutral and what is the voltage?"

I'll byte:

The neutral is the "stringer" and the voltage to Earth is 0 VAC at the Neutral Earth bonding point.
The bonding neutral (stringer) to Earth is in the breaker panel.

Note: "stringer" being the bare conductor cable physically supporting the L1 and L2 conductors.

[Harvard]

JaxDad wrote:
A farmer near here got pinched by the nice folks at our electrical utility a while back.

He had a very well lit barn and storage / shop building for his side business.

Then we had a power failure.......

When the linesmen went past they thought it odd that his outbuildings were well lit but not his house or anything else.

Then it dawned on them, there was a 500 KV transmission corridor running across his pasture.

When they discovered he ha buried a huge loop of wire zig-zagging back & forth beneath the transmission lines they handed hm a huge bill based on what they 'estimated' his consumption had been.

So much for 'free' electricity.......

This is a great story to tell because it is a head scratcher. So was it via inductance to the Magnetic Field or capacitance to the Electric Field. Unquestionably it was the latter and here is why:

The power line was severed downstream of the farm so there would be no current flowing (so no Magnetic Field) BUT the upstream portion over the farm was still powered up. So we have a full blown Electric Field over the farmers "capacitance plate" in the field.

A single conductor from the capacitance plate to the primary of his transformer and the bottom of the primary to a ground rod in Earth.

😉 😉 🙂

On second thought, the towers were on line but the local distribution was down So, it could have been inductance to the Magnetic Field. My bad.

[MEXICOWANDERER]

Look for the klystron Thyristors, at the end terminals. Both conductors you see are of similar orientation. Opposition polarity is hidden. Can you find it? 😉

[myredracer]

Harvard wrote:
Re: "Look at the insulators"

Where is the 3rd phase?

That would be a lower voltage "local" single phase transmission line, one hot and one neutral. Maybe 60 KV? The hot and neutral cancel out the EMF. Three phase 500 KV transmission lines (usually 3-conductor delta configuration, not wye) are more efficient and transit more power using comparatively smaller size aluminum conductors and less aluminum per foot. The 3 phases (180 degrees apart) also cancel out the EMF. Below is what a 500 KV transmission line looks like and are much taller.

Local residential/rural high voltage lines on streets (in Canada at least) are 12 or 25 KV and the high voltage primary and low voltage secondary (120/240) share a common neutral which is why you see only one insulator on the poles like in diagram below.

In the last diagram, which wire is a neutral and what is the voltage?

[Harvard]

road-runner wrote:
I once visited somebody whose back deck was a few hundred feet from some high voltage lines. On the deck he held up a fluorescent tube, and it lit up (not at full brightness).

So, it is pretty clear there was a voltage present, therefore the question, "was it induced, or what?"
I NOW think it was voltage from the Electric Field. In the past I would have guessed induction...

[JaxDad]

A farmer near here got pinched by the nice folks at our electrical utility a while back.

He had a very well lit barn and storage / shop building for his side business.

Then we had a power failure.......

When the linesmen went past they thought it odd that his outbuildings were well lit but not his house or anything else.

Then it dawned on them, there was a 500 KV transmission corridor running across his pasture.

When they discovered he ha buried a huge loop of wire zig-zagging back & forth beneath the transmission lines they handed hm a huge bill based on what they 'estimated' his consumption had been.

So much for 'free' electricity.......