I am so lost, anyone help?

[zog]

We had a tornado watch yesterday. It blew right by us, we were fortunate. Other counties around us got SLAMMED!!!!!!! They showed a helicopter hired by National Grid flying around with a huge "hoolhoop" test appartus slung 30' below the helicopter testing for fault conditions. What is this thing? I tried to look for pictures for you guys/gals on the net, yet to no prevail. Do any of you know what apparatus this could of been they were using to find faults? How does it work?????? I will continue to try to find pic's, but can any of you beat me to the answer on what that was? I am baffled, and that is nothing new. I am not all that familiar with utility work. The Grid guys here don't even wear full suits here, and that bothers me.
The helicopter flew over 50' above the lines. What the heck was this thing?????????????

Thanks in advance for your answers and knowledge. Always curious, always seeking knowledge. I am stumped on this one. Can someone fill me in:-?

We are doing a job right now using corona detection from a helicopter, but it dosent look anything like that, I am guessing it is Airborne Aucustical detection they are doing. I will have to ask my helicopte pilot about that rig next week.

 

[76nemo]

We are doing a job right now using corona detection from a helicopter, but it dosent look anything like that, I am guessing it is Airborne Aucustical detection they are doing. I will have to ask my helicopte pilot about that rig next week.

Thanks for keeping my question in mind zog. I'll never know anything unless I ask and be persistant I really appreciate the reply/s.:smile:

 

[djohns6]

080613-1309 EST

Todays experiment a few minutes ago.

I used a one turn rectangular coil 12 ft x 30 ft located about 30 ft below my primary lines for my flux detector. Measured voltage with a Fluke 27 was 0.5 MV sometimes dropping to 0.4 MV. From previous posts I have from my perspective a 3 phase delta distribution system.

Same length of wire and I changed it to a loop 40 ft by 2 ft. New reading 0.1 MV. Less flux coupling in this case because of the smaller cross-sectional area, 360 sq-ft vs 80 sq-ft. The voltage ratio corresponds to this change.

Yes it is possible to get some idea of the current in the lines. Although I could have a highly balanced load and see less induced voltage than an unbalanced line of lower current. What I see with this coil is the net flux coupling to the coil.

.

What is the purpose of this experiment ?

 

[gar]

080613-2015 EST

djohns6:

Two purposes.

First, this thread ask the question what the device below the heilcoptor might be for? I think that my experiment clearly indicates that a large load on a phase could be easily detected from flying over the lines with a large coil monitor. Also note my test was with one turn. Sensitivity can be greatly increased by using more turns. The voltage will be proportional to the the number of turns. The larger the coil area linking with the flux from the transmission line the greater the voltage also.

Second, I had previously measured ground voltages around my home. These were in the millivolt range. Inherently to make these ground voltage measurements I create a 1 turn coil. There is no way to avoid this. Thus, what is the likely magnitude of the 1 turn induced error voltage in making the ground potential measurements? I had assumed the error was insignificant, and this experiment proved this assumption to be correct.

When I did the second trial on ground potential measurements I found a very clean sine wave in some areas, and in others a moderately large harmonic content.

I have no idea how the three phase loading is distributed beyond me. It may be interesting to put down a temporary loop and observe the magnitude and waveshape of this signal at some different times of day. At night it should be low except for air conditioners cycling on and off. Correlating the timing with with my phase might show to some extent how the different phases are loaded downstream from me.

.

.

 

[djohns6]

Transmission lines are protected by circuit breakers and protective relay schemes . These relays need current and potential inputs to function properly . These same currents and potentials are sent via SCADA to dispatch centers where they are monitored on a real time basis .
Without going into a long spiel about the attributes of modern relaying , I'll just say that there are better ways to troubleshoot than dragging a coil of wire around the sky .

 

[zog]

Transmission lines are protected by circuit breakers and protective relay schemes . These relays need current and potential inputs to function properly . These same currents and potentials are sent via SCADA to dispatch centers where they are monitored on a real time basis .
Without going into a long spiel about the attributes of modern relaying , I'll just say that there are better ways to troubleshoot than dragging a coil of wire around the sky .

Fault was the wrong word to use in the news article, I think they are looking for Corona and/or partial dsicharge.

 

[gar]

080614-1544 EST

djohns6:

Do you have any idea what this large ring below the helicopter is for?

Someone has suggested calling the power company to ask what is this device. That seems to be a good solution for 76nemo pursue.

.

 

[K8MHZ]

What color was the helicopter?

Are all your cows OK?

 

[gar]

080614-1715 EST

K8MHZ:

Have you been involved with any farmers and "stray voltage" (really from stray current)?

If so, then what was the voltage to which the cows were subjected? And between what components (floor, watering trough, milking machines, or whatever)? Could you identify the cause of the stray current?

.

 

[djohns6]

080614-1544 EST

djohns6:

Do you have any idea what this large ring below the helicopter is for?

Someone has suggested calling the power company to ask what is this device. That seems to be a good solution for 76nemo pursue.

.

Nope , no idea . I asked one of the engineers at work and he didn't know either . Apparently , it's not a technology that we utilize at my company .