Grid Tie Problems

[Allgood-Energy]

I have recently had problems keeping my system grid-tied; because my main breaker keeps tripping.
I started this thread because others asked me to start it.
I have a 200 Amp Meter and Mains. The meter base has a divided base with the meter on the left and a 200 Amp breaker on the right. Picture shown. The incoming power goes from the 200 amp main to the knife disconnect on the right and back to the panel where the CB is and into the main's panel inside the house; the picture is also shown.
When I get a sunny day my production goes to 6 + KW and the loads I have are fairly small, less than 2Kw.
This is when the 200 amp main trips. The line-up of breakers between the inverter and the 200 amp main; is the 60 amp in the mini PDP, and the 60 amp in the main, which is considered the back feed breaker. I have never tripped either of these lower amperage breakers while back-feeding the grid. This is troubling, I have talked with some solar installers in the area and they say they have seen this particular breaker fail in this same way on their installations. The panel is a GE meter socket load center TSL420FCU and uses a plug-in main 200 amp breaker TQDL21200. This breaker is no longer manufactured by GE or anyone else. You can get used ones on the internet for about $2000. OHHH not me. I guess when ABB bought GE a few years ago they stopped making this junk. I guess rightly so.
So I have decided to replace the breaker, by opening the meter main and wiring the meter directly to the input side of the knife switch and adding a different manufacturer's breaker at the bottom of the knife switch enclosure. The knife switch was added to the incoming power chain when Rocky Mountain power required me to add it for the addition of this solar installation. This was not cheap this 200 Amp mains knife switch was over $600. But at least I now have a place to put the new breaker. So if the $600 wasn't enough to add insult to injury I now have to buy a new $500 breaker. Now I am wondering if this is all related to the spiking of power seen by some others using the XW-pro inverter build 49 firmware????

 

[JCSchwarb]

I have recently had problems keeping my system grid-tied; because my main breaker keeps tripping.
I started this thread because others asked me to start it.
I have a 200 Amp Meter and Mains. The meter base has a divided base with the meter on the left and a 200 Amp breaker on the right. Picture shown. The incoming power goes from the 200 amp main to the knife disconnect on the right and back to the panel where the CB is and into the main's panel inside the house; the picture is also shown.
When I get a sunny day my production goes to 6 + KW and the loads I have are fairly small, less than 2Kw.
This is when the 200 amp main trips. The line-up of breakers between the inverter and the 200 amp main; is the 60 amp in the mini PDP, and the 60 amp in the main, which is considered the back feed breaker. I have never tripped either of these lower amperage breakers while back-feeding the grid. This is troubling, I have talked with some solar installers in the area and they say they have seen this particular breaker fail in this same way on their installations. The panel is a GE meter socket load center TSL420FCU and uses a plug-in main 200 amp breaker TQDL21200. This breaker is no longer manufactured by GE or anyone else. You can get used ones on the internet for about $2000. OHHH not me. I guess when ABB bought GE a few years ago they stopped making this junk. I guess rightly so.
So I have decided to replace the breaker, by opening the meter main and wiring the meter directly to the input side of the knife switch and adding a different manufacturer's breaker at the bottom of the knife switch enclosure. The knife switch was added to the incoming power chain when Rocky Mountain power required me to add it for the addition of this solar installation. This was not cheap this 200 Amp mains knife switch was over $600. But at least I now have a place to put the new breaker. So if the $600 wasn't enough to add insult to injury I now have to buy a new $500 breaker. Now I am wondering if this is all related to the spiking of power seen by some others using the XW-pro inverter build 49 firmware????

A couple things come to my mind. How does your inverter handle Neutral-Ground bonding? If it applies an NG bond on DC current production, then a ground loop between your supply side and return side to your panel and main could cause an imbalance that may trip the circuit. I would ensure that your system has only one NG bond upstream of the inverter and that the inverter and other sub-panels are kept separate.

Further, many inverters have a ground wire on the AC input and output side. Only the AC input should be connected to the panel, otherwise another ground loop is created. If your main CB has Arc-fault or other imbalanced load detection, then it could be tripping because of that. Perhaps you could try only running balanced loads, 240VAC since the neutral return path would be near 0V as a quick test, then flip that off and run unbalanced loads and check your neutral voltage return path to see if it shows an anomaly.

My system would constantly trip my GFI’s until my NG bonding screws were removed in the inverter and it destroyed some electronics and HVAC.

 

[timselectric]

I think that you need to get an electrician involved to determine why the breaker is tripping. It could be a worn out breaker, or bad connection, or overheating, or ect, ect, ect.

 

[Allgood-Energy]

So here is the scoop on the home and Neutral ground. The house was added on in 2007, I added 1940 sq ft to the home, and in so doing the original 100 Amp main became a sub-panel and two more panels were added to the house. A 200 Amp main that you see in the pictures of the post above and another sub-panel for an indoor 8 X 14 Endless Pool.
The safety grounds and Neutrals in the original 100 Amp Main panel were never separated like they should have been when the new 200 Amp main was installed. I am working on that now since I am now adding three more Critical Loads panels that are next to the 3 distribution panels. This Solar Project has become a life of its own. The solar project was started in late June of last year and has taken me all this time to complete. I'll be 72 this coming year, and there has been a number of major challenges along the way. The first thing, the shipper of my solar parts damaged one of the mounting rails and a solar panel during shipping, the second was, I underestimated the slope of the ground where the array was to be installed. This oversight cost me about $3000 to rectify and 2 months delay in the project.
On November 27 I fell and broke my left humerus and since then I haven't been able to do much because of the excruciating pain. It's now been over 2 months and the bone is healed but there are some lingering problems with motion and strength. Hopefully, a physical therapist can help here. I am currently waiting for some better weather to install the other critical load panels and fix the grounds. I would fix the grounds but I am having trouble reaching with that left arm.

 

[JCSchwarb]

So here is the scoop on the home and Neutral ground. The house was added on in 2007, I added 1940 sq ft to the home, and in so doing the original 100 Amp main became a sub-panel and two more panels were added to the house. A 200 Amp main that you see in the pictures of the post above and another sub-panel for an indoor 8 X 14 Endless Pool.
The safety grounds and Neutrals in the original 100 Amp Main panel were never separated like they should have been when the new 200 Amp main was installed. I am working on that now since I am now adding three more Critical Loads panels that are next to the 3 distribution panels. This Solar Project has become a life of its own. The solar project was started in late June of last year and has taken me all this time to complete. I'll be 72 this coming year, and there has been a number of major challenges along the way. The first thing, the shipper of my solar parts damaged one of the mounting rails and a solar panel during shipping, the second was, I underestimated the slope of the ground where the array was to be installed. This oversite cost me about $3000 to rectify and 2 months delay in the project. I will continue in two hours.

Definitely get your NG bond’s straightened out. I agree with Tim regarding consulting with a local master electrician that has solar or at least generator experience. For a few hours in labor, he/she should be able to get to the heart of the issue. You may have several areas that need addressing.

 

[timselectric]

It's probably not a solar related issue.
Grid-tied solar should lesson the load on that breaker. Unless there is some leakage to ground from the solar.

 

[JCSchwarb]

It's probably not a solar related issue.
Grid-tied solar should lesson the load on that breaker. Unless there is some leakage to ground from the solar.

I would like to see the panel with the offending CB. A drawing would be helpful too. Are all the phases synced to the bus? I see a number of panels installed upside down so the red/black is reversed. Would like to ensure all the phases are traced out and validated.

 

[timselectric]

I would like to see the panel with the offending CB. A drawing would be helpful too. Are all the phases synced to the bus? I see a number of panels installed upside down so the red/black is reversed. Would like to ensure all the phases are traced out and validated.

The breaker is in the 3rd and 4th pictures.
This is a grid-tied system. So, kinda hard to mess it up.

 

[Allgood-Energy]

Today we had another good solar day. I decided to turn down the sell-back current from 25 Amps to 7 Amps and run the system to see if it trips the breaker. Ran it all Day without a problem with tripping.

 

[JCSchwarb]

Today we had another good solar day. I decided to turn down the sell-back current from 25 Amps to 7 Amps and run the system to see if it trips the breaker. Ran it all Day without a problem with tripping.

Very interesting. First thing comes to mind is bad breaker or loose wiring. Do you have a thermal tester? Perhaps check your connections are torqued. Test thermal temp loads at 7, 15, and 25 amps.

 

[JCSchwarb]

The breaker is in the 3rd and 4th pictures.
This is a grid-tied system. So, kinda hard to mess it up.

You crack me up Tim.

 

[timselectric]

You crack me up Tim.

It wasn't the goal.
I was just pointing out that there's only two hots to hook up. (L1 And L2) and it doesn't matter how you connect them. Grid-tied systems only put out 240v.

 

[Allgood-Energy]

Today I amped it up again to 10 Amps Sell. Seems to Run OK.
My question: Does the MPPT controls only produce what is required regardless of that what the solar panels have available? So if I have 7700 watts of the solar sun being generated and the loads on the Critical Loads and Main Panel Consume say 3200 watts that would leave 4500 watts to sell. Except the inverter is only rated for 6800 watts continuous. That means that with that load on the inverter, you could sell 2300 watts which figures to 9.583 amps of sell. As the load goes down, the allowed sell amps could go up.
How does the inverter handle these dynamics?
Say I have the Sell amps set at the maximum 27 amps is 6480watts to sell and the sun is shining and my loads are very low say 200 Watts. This would leave 120 watts of inverter capability. Does the inverter curtail the output to match the load and export sell current, and what happens if the loads and sell exceed the wattage rating in view that the inverter can source up to 12000 watts for 30 seconds?
I guess you have to remember that solar watts have to be available. My Array has a maximum output of 16 X 480 watts or 7680 which is 32 amps and you can only sell a maximum of 27 amps so that is only 5 amps of excess sun power left at maximum power which is 1200 watts above the 6480 equaling the 7680 watts, but this is 880 watts above the inverter continuous rating.
So how do you keep from tripping your inverter in those cases where your generated power exceeds your inverter capacity? I know this is all theoretical.
I don't have any historical numbers to go on, about the generation capacity, and or the loads.
I guess I'll have to be patient and wait and see what kind of problems will crop up.
I think I would like to buy a:

Smart Home Energy Monitor with 16 50A Circuit Level Sensors | Vue - Real Time Electricity Monitor/Meter | Solar/Net Metering​

https://www.amazon.com/dp/B08CJGPHL9

​

 

[timselectric]

It can only work within its limitations. (What it can draw from the panels)
And yes, if you consume less you can export more.

 

[Allgood-Energy]

It can only work within its limitations. (What it can draw from the panels)
And yes, if you consume less you can export more.

So, I guess what I am asking is: Is there somewhere you can find documentation explaining how the inverter acts during over-limit power generation? Does it have over-limit timers and what happens if the timers get reset for short periods, does the inverter have an overheat detection and shut down or does it curtail production? How does it protect itself? Are these shutdown errors, self-reset or do they have to be reset manually? Are these configurable or set in stone in the firmware?
I have 880 watts of excess power which could be a problem in the summertime when the PV is cranking. This excess power is nice during winter months when the sun is low on the horizon.

 

[timselectric]

does the inverter have an overheat detection and shut down or does it curtail production?

Both

I have 880 watts of excess power which could be a problem in the summertime when the PV is cranking. This excess power is nice during winter months when the sun is low on the horizon.

Solar panels don't push power. They only make it available. The SCC draws what it can, up to its limits.