Utility Poles, Again

[Tom Robbins]

An old run of wooden power poles adjacent to a nearby forest preserve were removed and replaced with steel versions during last winter. I am certain the power company had very good reasons for doing this, but I miss examining their surfaces to see how the light changed their texture during the seasons. This dumb knot was photographed and posted here several years ago - http://www.openphotographyforums.com/forums/showthread.php?t=9911

Old habits die hard, evidently, so the metal poles are now getting the same scrutiny their predecessors used to get. Someone's got to do it, right? I noticed that one of the ten poles near the preserve has a concrete base to which the pole is attached with a ring of substantial bolts, or studs, set in the concrete. My guess is that this might serve as an anchor for the group. (Any thoughts on this, Doug?)

Tower Base Study​

This is the thing with early morning light sort of skipping in from a low level. The steel of the tower is allowed to rust. The fastening nuts are tack welded to the tower, probably to prevent them from loosening through the years.

These poles won't change with time as the wood ones did, but their shadows will change with the seasons and with the time of day.

Canon 90mm t/s, three frames stitched for the pano.

 

[Doug Kerr]

Hi, Tom,

I noticed that one of the ten poles near the preserve has a concrete base to which the pole is attached with a ring of substantial bolts, or studs, set in the concrete.

In fact typically those "studs" are perhaps several feet long and are all welded to several rings of heavy reinforcing bar, making a sort of "cage" in order to get a serious "purchase" on the concrete foundation (as well as reinforcing it.) (This cage is called "the embedded hardware".)

My guess is that this might serve as an anchor for the group.

If the other poles are of a similar type, I would be surprised that they weren't anchored the same way to similar foundations. How are the other ones "set"?

Sometimes, though, if the line takes a bend, the pole at the corner is much sturdier, to not be bent by the net lateral force from the wires not being "in line" in the two directions of departure, and that may lead to it having a more serious foundation and anchoring situation. Is ther any chance that this is what we are dealing with?

Lovely shot in any case. Thanks.

Best regards,

Doug

 

[Jerome Marot]

This dumb knot was photographed and posted here several years ago - http://www.openphotographyforums.com/forums/showthread.php?t=9911

I noticed you wrote then that the pole would not go anywhere for the next couple decades. There is probably a lesson in that: "never count on things being as you expect when you plan to photograph them", maybe?

 

[Tom Robbins]

Hi Jerome, agreed!

Hi Doug, thank you for the info regarding the embedded hardware in the concrete base. The visible fasteners are just the tip of the iceberg, evidently.

The other steel poles in the line appear to be just poked in the ground, judging from appearances. I'm sure there is something more substantial underground, but it isn't visible to the casual observer. This was taken one morning about a week ago to photograph this year's nascent corn crop with the very old Osage Orange field posts alongside the brand new power poles.

Emerging Corn​

The pole with the concrete base is on the right, and is in line with the series behind it. As you surmised, however, it is located at a point where the line makes a slight jog toward the west before continuing northward behind the camera (behind my right shoulder as I framed this shot). The line begins at a tee junction just beyond the four-pole line switch visible above. The wooden switch poles were not replaced when the metal ones were installed, but the ceramic insulators were replaced with glass ones, and the switch components appear to have been updated.

Corridor V​

This is a closer look at the switch taken this February. The upgrade work was done during the winter months, probably to minimize the damage to the hiking trails in the preserve. The utility company has since smoothed out the ruts and planted grass seed.

 

[Tom Robbins]

Not that it contributes anything, but here's a view of the line as it vanishes toward the north about ten minutes before sunrise a couple days ago.

Over the Horizon​

 

[Doug Kerr]

Hi, Tom,

Hi Jerome, agreed!

Hi Doug, thank you for the info regarding the embedded hardware in the concrete base. The visible fasteners are just the tip of the iceberg, evidently.

The other steel poles in the line appear to be just poked in the ground, judging from appearances. I'm sure there is something more substantial underground, but it isn't visible to the casual observer.

Are those poles significantly smaller in cross-section than the one at the "pull" (where the line bends)?

They might possibly be anchored just as wooden poles often are: by having a substantial length placed in a hole in the ground, somewhat greater in diameter than the pole, and concrete being poured into the annulus.

The pole with the concrete base is on the right, and is in line with the series behind it. As you surmised, however, it is located at a point where the line makes a slight jog toward the west before continuing northward behind the camera (behind my right shoulder as I framed this shot). The line begins at a tee junction just beyond the four-pole line switch visible above. The wooden switch poles were not replaced when the metal ones were installed, but the ceramic insulators were replaced with glass ones, and the switch components appear to have been updated.

Yes, a lot of fascinating things happen as a line is "updated" or "upgraded". The evolution of different kinds of insulator is especially interesting. (I am not at all expert about that.)

When we were in Dallas, we had a one "platter" of a superseded ceramic insulator string in our museum (donated by the contractor making a major upgrade to a line - the guy said "take the whole string", but I had no room for such), but when we moved to Weatherford and downsized it was discarded.

Best regards,

Doug

 

[Doug Kerr]

Hi, Tom,

Not that it contributes anything, but here's a view of the line as it vanishes toward the north about ten minutes before sunrise a couple days ago.

Over the Horizon​

This is an especially lovely shot. Thanks.

For those not familiar with the design of these lines, the conductor at the top of each pole is the "static wire" and is grounded, perhaps at every pole. It is not really the "neutral" of the transmission scheme. Rather, its purpose is to manage the shape of electrostatic field caused by potential differences between clouds and the earth so as to minimize gradient concentrations that could trigger lightning strokes, and if a stroke does occur, to take it.

A clever alternative, saving the cost of the fourth conductor, is to place one of the actual transmission conductors at the top of the poles and have it perform that prophylactic/sacrificial duty. Every so often (perhaps at every pole), there is a path from the conductor to ground through a component that has an infinite resistance (is an open circuit) at the operating voltage of the line but will have a low resistance for the high voltages involved in a lightning stroke (much like the "varistors" used to clip power line voltage peaks in our "surge protectors"). Sometimes these are actually built into the "post-style" insulators supporting the top conductor.

In most power lines, the relative positions of the three conductors are swapped every so often ("transposition") for symmetry of various parameters (such as capacitance to ground). When the ploy of no separate static wire is used, transposition may be done more frequently so as to "spread out" the prophylactic/sacrificial duty of the conductors .

A disadvantage is that with a separate static wire we can be a bit nonchalant about a "nick" blown in it my a direct lightning strike, but such a nick in an actual "phase" conductor serving as the static wire can be more degrading to the line. (At the very least, it can encourage "corona discharge" at the nick, a loss of energy and a source of radio-frequency interference.)

Best regards,

Doug

 

[Tom Robbins]

Thank you Doug! I've always wondered about that fourth line atop the poles.

The scoop about altering the configuration of the current carrying lines is fascinating. My guess is that 60 hz and long conductors with the earth being a consistent distance away could result in something resembling a tuned circuit unless measures were taken to prevent it.

The steel poles installed without concrete bases may well have concrete used in some way. As I recall from my ham radio years as a kid, utility poles were prized by some as antenna towers, and typically 10% of their length were buried in the ground. This always seemed a bit too trusting of the strength of the soil, but judging from the fact that few old poles tend to wobble seriously out of plumb, it probably works OK most of the time.

Your comment about "nicked" phase conductors and the resultant RFI also brought back some fond youthful ham radio memories. There were several hams in the community who used to actively "sniff out" these trouble spots and work with the local utility company to resolve them. This benefited the radio buffs as well as the utility company, but the general public couldn't have cared less.

Speaking of insulators, this is an old Hemingray 42 installed on a pole alongside a railroad track that was abandoned 44 years ago. Any ideas about the little metal tags tacked to the wood?

Hemingray 42​

This is the railroad as seen last winter after a bit of snowfall. "Ghosts" of removed railroad ties are only now beginning to weather away. The lines to the right are part of another power line. The abandoned utility line is out of sight to the left. Farmland is valuable and the old remnant railroad beds are slowly vanishing.

Road Bed of CGW Railroad​

One thought leads to another, so I'd better stop now before getting too far off the track.

 

[Doug Kerr]

Hi, Tom,

Speaking of insulators, this is an old Hemingray 42 installed on a pole alongside a railroad track that was abandoned 44 years ago. Any ideas about the little metal tags tacked to the wood?

My guess is that this line carried railway signaling circuits and the tags may have identified the conductors, to facilitate trouble-shooting (although I don't recognize those particular designations, but I'm only an amateur at that field).

Best regards,

Doug

 

[Tom dinning]

I didn't realise poles were so...... so interesting? There are some big ones down the road so I'll check them out later. Meanwhile I had a hunt around nearer home and was as frustrated as the local dogs must be; we have underground power. Does that mean they build the poles up-side-down?
As a token gesture, I did find a few lamp posts. This one seemed a little insecure. Moreover, so did I, standing next to it. While photographing it a large hound looked at me suspiciously. By the look of it this is a meeting place or part of his territory.

I have no technical information regarding the pole other than it seems to be made of aluminium and has a light on top.

_D301612 by tom.dinning, on Flickr​

Here's a picture of the light.

20110707_0236 by tom.dinning, on Flickr​

By the way, Asher, have you noticed I have been centering? Pain in the arse, really but I thought I migh show some signs of submission. I have my limits, though. If you don't find a faster way of doing it I'll go back to my old nasty ways; you know, left of centre.

Cheers
Tom

 

[Asher Kelman]

Not that it contributes anything, but here's a view of the line as it vanishes toward the north about ten minutes before sunrise a couple days ago.

Over the Horizon​

That diagonal line to the tree on the left is a wonderful balance to the swathe of poles and wires. The spread of information from left to right goes from empty and then a general pattern to the uniqueness of that tree, where the eye has no chance but to stop!


Tom, that's an interesting good picture!


Asher

 

[Doug Kerr]

On the way back to Texas to attend Carla's grandsons high school graduation (report in a separate thread), on US 87 near Ackerly, Texas (actually quite near where we had seen elk earlier this year, and where we saw some mule deer this time - separate thread), I saw a chance to shoot some metal power poles to illustrate some of the foundation arrangements that were discussed earlier in this thread.

Here we see one of the "regular" poles in the line, mounted by direct embedment in a concrete foundation:

Douglas A. Kerr: Direct embedment metal pole​

We see a little bit of a bituminous (asphalt-like) coating on the part of the pole that is embedded in the concrete. It enhances the grip of the concrete on the pole, and also helps to avoid corrosion at the interface.

I don't know how deep such a foundation typically is or how far the base of the pole typically extends into it.

Here we see the line extending from this point:

Douglas A. Kerr: The line continues​

Yes, it looks as if the first pole is a little out-of-plumb (not vertical). (Yes, the whole picture is a little out-of-plumb as well!)

A little way down the line, there is a "pull" (change in direction). The pole there is a little fatter, and is anchored with embedded hardware - but I didn't get a chance to shoot it.

But a little farther along, there was a switched substation, and the line "dead ended" in both directions at fatter poles, anchored with embedded hardware.

Douglas A. Kerr: Switched substation​

Here we see, close-up, the anchoring of the rightmost of those two poles:

Douglas A. Kerr: Pole anchored to embedded hardware​

Best regards,

Doug

 

[Tom Robbins]

Tom, I like both of your beautifully centered photos. The second one, straight up at the light, appeared to be a computer mouse at first glance. The bird seems to be gazing at the moon. Interesting idea about the underground poles!

Asher, thanks for your kind words.

Doug, great examples. Another aspect of utility poles that has some variation is guying, or back stays. The various ways of accomplishing this seem to involve space available, height of the pole, accepted method at time of installation, among others. The wires are sometimes festooned with wild vines, or sometimes with climbing plants like morning glories purposely planted by someone to dress them up. This is a corner pole noticed last year while at a swampy area and originally after a different subject entirely—just turned around and thought, hey, all those wires are sort of neat.

Corner Wires​

Not much of a photo, but I had the satisfaction of knowing that I prevented a few mosquitoes from starving to death that morning.

 

[Doug Kerr]

Hi, Tom,

Another aspect of utility poles that has some variation is guying, or back stays. The various ways of accomplishing this seem to involve space available, height of the pole, accepted method at time of installation, among others.

Indeed. Often the guys will run almost horizontally (perhaps across a roadway) to another pole, and then diagonally to the ground anchor. (The is a special name for that other pole, but it escapes me for the moment.)

Best regards,

Doug