Utility AC too high. Set Xantrex XW 6048 limit lower?

lelson

For years, utility voltage was steady at 120VAC. Recently noted odd behavior with some appliances (microwave, chest freezer). Concurrently, got faults with both grid tie Sunny Boy and Xantrex inverters in early morning. Utility (AC1) occasionally offline (protected circuits showed change to battery backup). Odd thing was that unprotected circuits were still energized. After reviewing documents, I think this made sense. The utility admits several large voltage regulators in the substation failed and pegged high (134VAC). They're working on a permanent fix and instituting temporary fixes (linesmen manually adjusting voltage as loads change daily).

In the morning, usage is low, voltage goes up. When the sun comes up, the inverters try to match the high utility voltage and fail to do so at some (+5%?) voltage. Once the AC1 voltage reaches the advanced settings limit (AC1 Hi Volt set to default of 132V), the Xantrex disconnects from the utility. The protected circuits then are fed by the battery (and ultimately by the generator). Once the utility (AC1) drops below 132 for the required 300 seconds (as the day warms up and neighbors turn on their A/C, lowering the voltage), the Xantrex re-connects to the grid.

Although this has been a steep learning curve for me, other (old) posts on this Forum have addressed this in what I consider an odd way:their response to out of range utility voltages is to increase AC1 Hi Volt so the Xantrex remains connected to the utility. Utility linesmen say this can "burn down a house". At the very least, appliances can be damaged. The average neighbor will just think it is about time for his $10K fridge to burn out.

So here's my question: given that the standard tolerance for utility 120 AC is +-6V (5%) why doesn't it make sense to set AC1 Hi Volt to 126 and AC1 Lo Volt to 114? This would at least protect some of my appliances from this insidious situation that can happen with no warning.

Dave Angelini

lelson said:

For years, utility voltage was steady at 120VAC. Recently noted odd behavior with some appliances (microwave, chest freezer). Concurrently, got faults with both grid tie Sunny Boy and Xantrex inverters in early morning. Utility (AC1) occasionally offline (protected circuits showed change to battery backup). Odd thing was that unprotected circuits were still energized. After reviewing documents, I think this made sense. The utility admits several large voltage regulators in the substation failed and pegged high (134VAC). They're working on a permanent fix and instituting temporary fixes (linesmen manually adjusting voltage as loads change daily).

Probably XW is in passthru.  Wait for them to fix, if you can. Have them repair any damage!  Nevada Energy?

In the morning, usage is low, voltage goes up. When the sun comes up, the inverters try to match the high utility voltage and fail to do so at some (+5%?) voltage. Once the AC1 voltage reaches the advanced settings limit (AC1 Hi Volt set to default of 132V), the Xantrex disconnects from the utility. The protected circuits then are fed by the battery (and ultimately by the generator). Once the utility (AC1) drops below 132 for the required 300 seconds (as the day warms up and neighbors turn on their A/C, lowering the voltage), the Xantrex re-connects to the grid.

They need to fix this.

Although this has been a steep learning curve for me, other (old) posts on this Forum have addressed this in what I consider an odd way:their response to out of range utility voltages is to increase AC1 Hi Volt so the Xantrex remains connected to the utility. Utility linesmen say this can "burn down a house". At the very least, appliances can be damaged. The average neighbor will just think it is about time for his $10K fridge to burn out.

So here's my question: given that the standard tolerance for utility 120 AC is +-6V (5%) why doesn't it make sense to set AC1 Hi Volt to 126 and AC1 Lo Volt to 114? This would at least protect some of my appliances from this insidious situation that can happen with no warning.

If you do this the XW will just be on battery more as you are decreasing the range the utility will continue to power protected loads.  I would do this in your situation but there always is the law of unintended consequences. What does your installer say?
I know they are long gone...  XW6048 is the .oldest of 3 XW generations BTW

  I would really make sure you have surge protection on XW inputs and whole house loads.  Good Luck and where are you?

Dave Angelini

If your solar can support your loads,  this would be a great time to go offgrid until it is fixed !  Good Luck from Gardnerville!

lelson

Dave Angelini said:

If you do this the XW will just be on battery more as you are decreasing the range the utility will continue to power protected loads.  I would do this in your situation but there always is the law of unintended consequences. What does your installer say?
I know they are long gone...  XW6048 is the .oldest of 3 XW generations BTW

  I would really make sure you have surge protection on XW inputs and whole house loads.  Good Luck and where are you?

The way I see it, a big part of the reason for solar is to help during grid failures. Up til now that meant when the grid was down but "burning down my house" might be considered a grid failure. Sure, using the batteries for a few hours has financial consequences, but I think the tradeoff is good. My question was really "what (other) unintended consequences" might I expect?

Yep. Independent Power Corp went belly up some time ago Still love the XW6048 here in N. Douglas County. Thanks for your input...

Dave Angelini said:

If your solar can support your loads,  this would be a great time to go offgrid until it is fixed !  Good Luck from Garnerville!

Dave Angelini

Other consequences ?   I do not know all the particulars of your situation. I do this for a living. I have seen so many weird installations and people doing crazy things with electricity and their homes. Hopefully they get this fixed soon.

Good time to back up your data😉

Douglas county was rocking Saturday night at Bally's. We saw the Led Zep tribute band Zoso. They were really good!

lelson

Dave Angelini said:

If you do this the XW will just be on battery more as you are decreasing the range the utility will continue to power protected loads.  I would do this in your situation but there always is the law of unintended consequences. What does your installer say?
I know they are long gone...  XW6048 is the .oldest of 3 XW generations BTW

  I would really make sure you have surge protection on XW inputs and whole house loads.  Good Luck and where are you?

The way I see it, a big part of the reason for solar is to help during grid failures. Up til now that meant when the grid was down but "burning down my house" might be considered a grid failure. Sure, using the batteries for a few hours has financial consequences, but I think the tradeoff is good. My question was really "what (other) unintended consequences" might I expect?

Yep. Independent Power Corp went belly up some time ago Still love the XW6048 here in N. Douglas County. Thanks for your input...

Dave Angelini said:

If your solar can support your loads,  this would be a great time to go offgrid until it is fixed !  Good Luck from Garnerville!