In click send by accident. This is the rest of my post.
In click send by accident. This is the rest of my post.
There has been sent me very interesting posts.
It all goes back to insulation being based upon maximum maximum permissible temperasturethat will
There has been sent me very interesting posts.
It all goes back to insulation being based upon maximum maximum permissible temperature that will cause degadation of the insulation to half its original value in an estimated 20,000 hours. The insulation half-life is based upon the fact that insulation life is reduced by half for each 8-10degc increase in insulation temperature.
Starting at this point then assuming that the OP is referring to a ventilated dry type distribution transformer the insulation temperature is normally today 220degC. The transformers's KVA rating is then based upon a 40degC ambient plus 150degC rise plus a necessary winding hot spot of 30deg which adds up to 220degC. Thus, consider the ambient temperature to be less than 40deg C which will increase the transformer life.
But, industry std for the rated kva is based upon 30degC. Thus, the load must be decreased by 1% or every degree above and can be increased 0.67% for every degC below. This is based upon the transformer rating. Of course the common transformer is very seldom loaded to its rating.
The average temperature should be for a 24hr period with a max temp not more than 10degC greater than the average temp.
But puting all that stuff asside it is expected that a dtdt's life expectancy should be about 35 years based upon an avg 35% loading. When loaded at 100% expect 3-5 years based upon a 30degC amb a degC max. The +10degC over 30degC should be balanced with the same time at 10degC below.
Please note that for every continuous 10degC above 30degC reduces the life by 50%.
Then, there is also the 115 and 80degC rise transformers. Note that both still have 220deg insulation class so when operated at 30degC ambient there transformers will have a longer life.
And now the good part of the 115 and 80degC rise transformers is that the 115degC can carry an additional 15% overload and the 80degC rise can carry an additional 30% overload without exceeding its insulation class.
So, transformer life? There are many thing that can be considered the revolve around ambient temperature and the loading.
I am considering bringing in the evil high wire to my off-grid house. There are two potential routes: one is 1000 feet and the other is 2200 feet. The shorted route may incur highest utility connection charges as the end point of my line would still be a few poles away. The shorter route is short enough that it could be done with 4/0 or maybe 250 AL for about 3K. For long route, I have a real hairbrained plan :angel: I am considering stepping up to 2400 and sending over on 2KV #12 PV wire sleeved in 1/2 PVC. I found two of these transformers for pretty cheap. The advantage of this is it is about half the cost for materials (potential a lot less overall If utility charges more for the shorter route) and trenching is much easier as I can use my mini edger which makes a 1 inch wide trench. Codes are not an issue here, but I do want something reliable and functional.