Electrical equipment life span? 1

[swz202]

I am presently working on the evaluation and cost estimation of upgrading a 40+ years old gas plant. Want to have some idea what is the normal life span of transformers, switchgears, motors, cables, etc.

Thanks in advance.

 

[Zogzog]

Thats a tough question to answer, the IEEE has some life expectancy guidelines (Red book I think) but that is like asking how long a car lasts, depends on how you drive it and how well it is maintained.

Personnaly I do not consider 40 year old switchgear to be that old, in michigan most of the automotive plants have equipment at least 40 years old, some facillites have equipment from the 1920's that has been maintained well and still works better than some power systems that are only 10 years old that has been neglected.

 

[asymptote]

In the UK Utility, distribution equipment such as transformers, cables and switchgear was thought to have a economic life of 80 years. Motors are a different can of worms as the forum will no doubt tell you.

 

[AusLee]

The first thing to ask for is the maintenance records. If none is available for a piece of equiment then doom it to be used as spare parts.

Depending on your contract, you might want to make some tests, such as: insulation test for the cables, transformer windings, oil, etc. although i do not suppose you will be reusing the oil.

Cables have a manufacturer's guarantee for 50 years. However you should see the site conditions and if any derating factor should have applied.

Diesel generators last 15,000 to 20,000 hours.

40 years ago, there were no PLCs. Therefore you need not waste any time on the control, all goes to the dustbin as the relays are not reliable after all these years, unless some rehabilitation works have been carried out recently, which should be 10 years ago in your case because that is how long it normally takes a decicion to upgrade, and when an upgrade is coming, maintenance cesases.

For the motor, the electrical part can be "cleaned", but the shaft may have worn out from the mechanical loads (fatigue).

It will help more if you provide a list of items.

On the other hand, renovation means a job for the next decade or so, and i sincerely doubt that a 40 years old structure is adequate to sustain demolitions and connections, you will see they were using diffferent kinds of steel.

All low current devices also go to the dustbin, but i also doubt they are still using mechanical telephone exhanges or 10BaseT data networks ...

 

[swz202]

I'm going to spend a couple days there to do some site investigation and inspection. At this point I have little information about this plant.

Thank you guys all for your helpful information.

 

[unclebob]

Old guys here say that the life span of transformers
goes from a few cycles to 100 years.