Primary vs Secondary Oncor Texas service

[betajuice]

I am setting up a 400 kW farm and just want to sanity check if anyone has experience with primary power from oncor. (The deal is, own and manage your own transformer and get a reduced delivery cost.)

I want to know if I am missing something here because it seems like it is worth it. Savings ~ $0.004 / kwh.

A lot of utility people have never even done primary power so I want to get opinions from other miners if this makes sense.

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[DaveF]

Had 2 customers do it here in NY/NJ and someone else in FL. Not mining related, just manufacturing

Saved them a lot.
BUT:

1) Everything is 'your fault' not the fault of the power company until you can prove otherwise when it comes to low power issues. 3 states, 3 different power companies, same BS.
2) If you do have issues they will not even test TO the transformer without your electrician being there.
3) If you do need parts / repair you can be down for a while. Unless you have a spare $50k transformer sitting around like the power company does.

For my customer that had a lot of issues it was stressful and annoying, but they could function on a limited bases.
A mining facility is going to be off....

-Dave

[betajuice]

Had 2 customers do it here in NY/NJ and someone else in FL. Not mining related, just manufacturing

Saved them a lot.
BUT:

1) Everything is 'your fault' not the fault of the power company until you can prove otherwise when it comes to low power issues. 3 states, 3 different power companies, same BS.
2) If you do have issues they will not even test TO the transformer without your electrician being there.
3) If you do need parts / repair you can be down for a while. Unless you have a spare $50k transformer sitting around like the power company does.

For my customer that had a lot of issues it was stressful and annoying, but they could function on a limited bases.
A mining facility is going to be off....

-Dave

#1: What do you mean by "low power issues" ?
#2, who won't test the transformer?

thanks for the advice

[philipma1957]

Had 2 customers do it here in NY/NJ and someone else in FL. Not mining related, just manufacturing

Saved them a lot.
BUT:

1) Everything is 'your fault' not the fault of the power company until you can prove otherwise when it comes to low power issues. 3 states, 3 different power companies, same BS.
2) If you do have issues they will not even test TO the transformer without your electrician being there.
3) If you do need parts / repair you can be down for a while. Unless you have a spare $50k transformer sitting around like the power company does.

For my customer that had a lot of issues it was stressful and annoying, but they could function on a limited bases.
A mining facility is going to be off....

-Dave

#1: What do you mean by "low power issues" ?
#2, who won't test the transformer?

thanks for the advice

low power issues would be the transformer you have say a 500kva  that should put out 240 volts is doing 201 volts.

You will need to test the transformer with your guys not the power company guys.

you will need to swap in a spare with your guys .

here is a 500kva which would likely work for you (don't believe me do more research)

https://www.apc.com/us/en/product/PMM500-CUB/power-distribution-unit-500kva-copper-transformer-480v-input-208v-output-configurable/


if it is putting out under the rated 208 volts your mine won't work
it will be up to you to repair and test that transformer.

[NotFuzzyWarm]

#1: What do you mean by "low power issues" ?
#2, who won't test the transformer?

Low power means what it says: Voltage drops out of spec under heavy load - OR - there is a local brownout that causes a lower than normal voltage from the utility. Either way you have to pay for someone to test/verify what you are seeing.

Testing the transformer: Due to the incoming voltages used, transformers tied to utility power lines are almost always oil-filled. The dielectric oil used provides both insulation as well as cooling. Most utility guidelines require the condition of the oil to be tested every few years to monitor its breakdown over time. You'll have to pay for that. If there is an issue with your voltage dropping when under full load, that can be checked using a (huge truck mounted) resistive load bank to provide known loads ranging from several 10's of kw to over several MW to the load side of the transformer. Most large cities have several companies that provide that service and it is NOT cheap.

In short, if you have ANY power issues you have to pay for it to be diagnosed.

Oh btw: that link Phil gave is not for a main incoming power transformer - the utility side is usually over 4.8kVAC and more typically either 9.8 or 13.2kVAC - not 480v.

[DaveF]

#1: What do you mean by "low power issues" ?
#2, who won't test the transformer?

Low power means what it says: Voltage drops out of spec under heavy load - OR - there is a local brownout that causes a lower than normal voltage from the utility. Either way you have to pay for someone to test/verify what you are seeing.

Testing the transformer: Due to the incoming voltages used, transformers tied to utility power lines are almost always oil-filled. The dielectric oil used provides both insulation as well as cooling. Most utility guidelines require the condition of the oil to be tested every few years to monitor its breakdown over time. You'll have to pay for that. If there is an issue with your voltage dropping when under full load, that can be checked using a (huge truck mounted) resistive load bank to provide known loads ranging from several 10's of kw to over several MW to the load side of the transformer. Most large cities have several companies that provide that service and it is NOT cheap.

In short, if you have ANY power issues you have to pay for it to be diagnosed.

Oh btw: that link Phil gave is not for a main incoming power transformer - the utility side is usually over 4.8kVAC and more typically either 9.8 or 13.2kVAC - not 480v.

It's not that they will charge you to test the power that coming into the transformer form the local power company. It's the fact that the will not even DO it until you have your electrician onsite. Being charged by your person is a different issue.

If everything goes well there can and will be a cost savings. You just should be aware that there can be some major expenses that you can get hit with.

-Dave

[DaveF]

This just popped up in my newsfeed:

https://beincrypto.com/texas-lawmakers-pass-bill-limiting-bitcoin-mining/

Don't know if it will pass and if it does if it will matter to you but it's something to think about.
If you live there and were setting up the mining farm because of that it's one thing.

If you live elsewhere and were setting it up there because TX is giving miners good deals, keep in mind that might not be the case soon.

-Dave