Data Collector wiped out by electric transformer

> It sure makes me think twice before locating a transformer pad with a robot rod or GPS rover. Shoot that rascal in reflectorless.

I've had my Allegro CX hard up against more pad-mounted transformers than I can count, with nary a hiccup. I'm more inclined to attribute the problem to coincidence than electromagnetic interference.

I have relied on a NGS tidal benchmark for a GPS control network. I have occupied it 50+ times (good RTK base for work in the area) It is far too easy to place things on top and I have not had an issue with the following:
Topcon Hiper XT
Topcon FC100
Topcon FC120
Topcon FC2500
Sokkia GSR2300 receiver and antenna
TDS Ranger

I have wondered about the hum and if that would cause an issue, but the results have been fine and dandy. Now if they would only put an outlet on it for me to leave a base setup for a couple days.

It can happen..

but probably not often. If it does, the facilities are NOT functioning properly.

I lost all the job files AND the screen on a Ranger DC inside a sub-station. It's only happened once...which makes me TWICE shy.

We had a main board in a Topcon Total Station fried while working in an energized substation.

Hope he was wearing his tin foil helmet and a cup.

Thanks for the heads up.

On one hand, I've located hundreds of transformers with the rover and never had a problem.

But I also remember when I was outside a radio tower site up in the mountains and the engineer warned me not to bring any electronics inside the wall because they would be fried.

I've only worked in and around substations twice, and it was with a conventional total station (Topcon GTS-302). In both cases we were uncomfortably close to 60kv lines, but neither people nor equipment suffered any noticeable effects. I don't discount the possibility of damage to either under the right circumstance, though.

Same with transformers, I suppose, though my experience with them is much more extensive with no ill effects. As Paden indicated, the transformer would probably have to be operating outside its normal parameters in order to damage nearby equipment.

From what I was told, it can happen if there is a electro-static discharge.

Most times, you wouldn't even know it happened.

There was actually discussion about using "grounding devices" when working around the high voltage equipment.

:rain:

There are two aspects of working around power equipment, electric field (the AC version of static electricity) and magnetic field.

If there is sufficient electrical field around a transformer to affect equipment, it could be a danger to people as well, due to lack of grounding. This would be extremely rare for a transformer. Inside a substation or near a radio transmitter, you might get sufficient electrical fields to create problems for equipment, even when human safety precautions are taken.

The magnetic field is not going to be a problem for people or pets, but in rare instances could induce problems in electronic equipment. A transformer mounted outdoors should have an iron casing that would shunt most of the leakage field before it gets to your equipment, but some rare circumstance could create a problem.

If you hold an iron object near the transformer (not in contact) and feel it vibrate, then I'd keep my equipment away from there.

I've never had it happen with transformers, but more than once I've had DC's get their brains scrambled while working under sizzling high tension power lines.

magnetic fields

DC and AC magnetic fields, while basically similar, have very different characteristics. While a static spark is generally a release of charged particles that have built a potential, they are mostly DC. Anytime AC has the potential to jump an arc, you don't need to be anywhere around.

Any time current flow through a wire a magnetic field is generated. If that current is DC the resultant magnetic field has a constant orientation. If the current is AC the magnetic field will vary in direction and intensity, hence the term AC magnetic field. This is also known as radio frequency radiation. It can vary in frequency in Extremely Low Frequency all the way up to Extremely High Frequency depending on the environment and the harmonics.

Of course a static spark can wreak havoc with our digital equipment. However my hunch, with DCs being wiped out in proximity to sub-stations and transmission towers, is that RF is more the culprit than a static charge.

magnetic fields

When I had problems I was running Husky FS2's. Static electricity was the culprit. Touching the instrument, cable, or DC would produce a static shock. A small jolt would turn the DC on/off, larger jolts would result in a hard reset of the DC. I learned to set the instrument up, connect everything, and then keep the DC in my hand for the remainder of the setup to prevent the static discharges.

I've never run my robot under those conditions but I have some work later this week that will force me to setup at least once under a dip in the high tension wires. I'll be watching for strange behavior and triple checking everything.

Or a good Faraday suit ?.

Faraday cages

Round here we call them a hen house or dog house and I'm not comfortable as to stay long in either.

About 15 years ago, we were traversing down the clearing of a TVA transmission line. The electrical wires were about 100 feet overhead but we could here the buzz of the static in the air. While preparing to take a measurement, I reached for a key on my HP48 and the screen turned off. I assumed that the timer shut it off so I turned it back on. This time, it turned off when my finger was about 2 inches from the keyboard.

This was repeatable so I called my partner over to see. We decided that we might be pushing our luck and needed to get some distance from the static. I don't remember how we took the shot. Maybe we wrote it down and moved on. Weird.

He told me that he once had a different problem under some power lines.
While carrying his aluminum tripod on his shoulder, he heard a buzzing sound. Wondered how a bee could be inside the tripod leg. While listening closely, static zapped him on his ear and he thought he was stung by the mystery bee!
Had a chuckle at himself when he realized what had happened,

I was working under a TVA line this afternoon. This was one of the monsters with three bundles of three conductors, 500KV I believe. The towers are located on either side of the hilltop and the lines dip to within 40-50 ft of the hilltop. I kept the robot down the hill close to one of the towers where the lines were much higher and saw no problems with the robot or DC even when I took the rod to the top of the hill.

I know not to work high-rod anywhere near transmission lines. However, I thought I could raise it to just above my head safely. Carbon fiber rod with aluminum clamp and center pole. As soon as I loosened the clamp and started to raise the pole I started getting shocked. Less severe than a hot electric fence but about double the worst shock I've ever gotten on a cold, dry, winter day after pulling off a fleece lined coat and reaching for a door knob. Later I noticed that even reaching up to reposition my hat would make the hair on my arm stand up. It's both amazing and frightening how much energy leaks off those lines.

I once got zapped by touching an AM radio tower. All the steelwork of the tower was charged, which I hadn't previously known about. No harm done, probably because it was RF rather than regular AC. Still have a little scar where the spark burned me.