Component lifetime

[gar]

171114-1233 EST

What have been the lifetimes of wood electric power poles? Will new poles last that long? I believe some poles I am aware of have been there since the early 20s, thus about 100 years. Many poles I know about are at least almost 70 years old.

What are the lifetimes of pole transformers?

How does an unloaded pole transformer life vary with applied voltage?

Apply full rated load current, then how does lifetime vary with applied voltage?

Is electrical or mechanical stress (note electrical produces mechanical) the primary cause of failure?

.

 

[K8MHZ]

171114-1233 EST

What have been the lifetimes of wood electric power poles? Will new poles last that long? I believe some poles I am aware of have been there since the early 20s, thus about 100 years. Many poles I know about are at least almost 70 years old.

What are the lifetimes of pole transformers?

How does an unloaded pole transformer life vary with applied voltage?

Apply full rated load current, then how does lifetime vary with applied voltage?

Is electrical or mechanical stress (note electrical produces mechanical) the primary cause of failure?

.

My daughter is mapping out poles for Consumers Energy. One of the things she has to keep track of is what kind of wood the poles are made of. She may know how old they are. I will ask her and if she does, I will post it here.

 

[hbiss]

I believe the old creosote treated poles lasted a good deal longer than the current pressure treated. I agree that the wood species and age of the tree has something to do with it also.

-Hal

 

[Ingenieur]

http://members.questline.com/Article.aspx?articleID=12304&accountID=1874&nl=13764

Transformers

The expected life of distribution transformers is about 25 years, according to ABB power products, a transformer manufacturer. The Copper Development Association reports that "transformers typically can be expected to operate 20 to 30 years or more." The manufacturing specification for distribution transformers is covered under the standard IEEE C57.12.00-2000 Standard General Requirements for Liquid-Immersed Distribution, Power, and Regulating Transformers published by the Institute of Electrical and Electronics Engineers (IEEE).
For proper transformer sizing, consider load profile characteristics and other factors. Note that transformers can be overloaded to some degree, but only for a certain amount of hours. Consult with the manufacturer to identify overload characteristics for specific transformers. For transformer thermal loading beyond nameplate in the U.S. and international marketplace, follow the IEEE/ANSI Standard C57.91-1995/Cor 1-2002 Guide for Loading Mineral-Oil-Immersed Transformers as the primary guide.
A substation preventive-maintenance program is necessary, not only for the protection of the substation equipment, but also to protect the ability of the commercial or industrial facility to operate with minimal downtime. Although there are many tests to determine the condition of transformers and their insulating fluids, we recommend the ASTM Transformer Oil Tests and Dissolved Gas Analysis tests as good starting points in diagnosing the health of your transformer.

interesting https://www.imia.com/wp-content/upl...-LifeCycleManagement-Utility-Transformers.pdf

 

[K8MHZ]

My daughter said the oldest pole she has seen was from 1936. It is still in service. She is just mapping circuits using GPS, not looking for poles that need to be replaced. No idea on how long the 1936 pole will stay in use. I am sure there are older ones as she is part of a large crew mapping circuits for Consumers. She maps about 50 poles a day, and has been doing it since the middle of June, and has only seen a small percentage of all of them being used. I think she said there are 2 million poles that need to be mapped.

 

[K8MHZ]

I believe the old creosote treated poles lasted a good deal longer than the current pressure treated. I agree that the wood species and age of the tree has something to do with it also.

-Hal

My daughter said there are only two kinds of wood used in the poles she is mapping. Red Pine and White Pine. She can tell the difference at a glance.

 

[retirede]

My daughter said there are only two kinds of wood used in the poles she is mapping. Red Pine and White Pine. She can tell the difference at a glance.

I had always thought that red cedar was used for poles many moons ago. But I've been wrong more times than I care to admit.

 

[GoldDigger]

I had always thought that red cedar was used for poles many moons ago. But I've been wrong more times than I care to admit.

It may be influenced by what species are available reasonably locally too.

Sent from my XT1585 using Tapatalk

 

[ActionDave]

I had always thought that red cedar was used for poles many moons ago. But I've been wrong more times than I care to admit.

I don't think they would grow tall enough. If they do I don't think they would grow fast enough. That's why pine is so common.

 

[retirede]

I don't think they would grow tall enough. If they do I don't think they would grow fast enough. That's why pine is so common.

Makes sense.

 

[gar]

171115-0930 EST

Lots of interesting information.

Just went out and looked at my poles, 3 of 5, all three were MBT Co with no date. There are newer tags with 2000 and 2010 markings. MBT stands for Michigan Bell Telephone Co. which became Ameritech, and now AT&T. The MBT poles date from at least 1960, and possibly 1950.

Where I grew up the poles were planted about early to mid 1920s, and I do not believe many have been replaced.

K9MHZ, how is your daughter able to date a pole? Are there date codes on older poles owned by Consumers as distinguished from MBT?

Ingenieur: your long reference was quite interesting. So there are a lot of possible ways for failure to be a direct result of a mechanical failure. I have been wondering if one can consider a dielectric breakdown in some cases to be a mechanical failure rather than electrical.

On my block possibly 2 transformers have failed in the almost 60 years of the installation. There about 30 homes on the block. My 25 kVA transformer was one and it was an oil leak. This transformer was not overloaded, 2 homes with gas for heavy power loads. My average load is 1 to 2 kW. Now have a 50 kVA transformer. Within a reasonable distance of my home I don't believe there is anyone with solar power, and possibly no EV cars requiring chargers. Quite a few Hybrids. There are at least two different 3 phase installations. The 50 kVA transformer is possibly an assumption that there will be EV cars, and/or solar in the future.

What sort of started this thread was that on Friday I am going to take an ESD (Engineering Society of Detroit) tour of the very high voltage lab at Kettering University in Flint. Kettering was originally GMI (General Motors Institute) and is located near the University of Michigan Flint campus.

Back when I was very young and until my late 20s our power cost was 2.5 cents per kWH. It is now about 16 per kWH. By some estimates the value of the dollar over this time has depreciated by a factor of 30. Even if you used 10, and it is definitely worse than 10, our present cost is less than when I was young. This lower real cost was mostly a result increased efficiency of power generation.

To try to keep the cost of electricity low and ignore the infrastructure is a major mistake. Everyone needs their own generator. Where are very large transformers made? How long to make one? How many backups are available?

Looking for information on the Ford Highland Park power plant I did not find what I wanted, but came across this interesting link:
https://en.wikipedia.org/wiki/List_of_power_stations_in_Michigan

.

 

[K8MHZ]

This, from my daughter:

There will usually but not always be a brand on the pole. The 595 at the top means this pole was placed may 1995. The 6 40 at the bottom means it was a class 6 (the size it is around) and 40 feet high


The 1936 poles have a little tag on the pole that says that stuff rather than a brand. If I see another one of those I’ll send a picture.

 

[gar]

171115-1224 EST

K8MHZ:

Looked at 2 of my poles and within a convenient visible range I did not find any branding. It is raining outside so I did not get out spyglasses to look higher up the pole.

.

 

[K8MHZ]

171115-1224 EST

K8MHZ:

Looked at 2 of my poles and within a convenient visible range I did not find any branding. It is raining outside so I did not get out spyglasses to look higher up the pole.

.

She is just doing poles for Consumers. If DTE does mark their poles, they may use a different method. Also look for metal label plates, I have a pole with such a plate on my corner.

 

[K8MHZ]

I just found this on a search:

Branding --- In the United States, utility poles are marked with information concerning the manufacturer, pole height, ANSI strength class, wood species, original preservative, and year manufactured in accordance with ANSI standard. This is called branding, as it is usually burned into the surface; the resulting mark is sometimes called the "birth mark".

 

[gar]

171115-1440 EST

K8MHZ:

I will look for a DTE pole as distinguished from an MBT pole and see if there is branding.

I took off on a tangent to see about DTE power distribution, and came across the following very interesting discussion:
Page 1 is probably not as interesting as page 2.
https://www.detroityes.com/mb/showthread.php?12233-The-Electrification-of-Detroit
https://www.detroityes.com/mb/showthread.php?12233-The-Electrification-of-Detroit/page2
A very long read, but many interesting points about interconnecting plants, and voltages.

My uncle joined DTE in the mid 1920s after graduating from the U of M. To the best of my knowledge he was in overhead lines until about 1950 when he became chief field engineer for unground lines, he liked non-office work. I looked to see if there was mention of a line he worked on around the early 1950s. This was a high voltage underground line around the western side between power plants on the north, and south sides of Detroit. There was an overhead line discussed, but no mention of this underground line. I don't remember the voltage, but from reading the discussion my guess is 120 kV. They may have used pressurized nitrogen to reduce the insulation problem at high voltage underground.

.