Voltage from grid too high. Is it possible to change XW6048 maximum voltage setting?

[bakunin]

We've been getting high voltage from the grid (AC1) ever since we installed our system. Everyday we get an F31 fault for over voltage. Through some observations I found the following:
-Voltage typically went over 130V around midday and stays around 122-124V at night.
- Our house is just outside a coast guard base which recently installed a solar system with panels in every single structure in the base (over 1,000 panels)
- If clouds appear in the area voltage will go down, sometimes as much as 7V. If the clouds go away (during midday) voltage will once again increase.


From these findings I concluded that the coast guard's system is so big (remember over 1,000 panels) that it is increasing the voltage on the grid causing our inverter to disconnect everyday around midday (safety regulation?). I have spoken to the power company and our contractor, neither one was aware of the problem. The power company verified the voltage is too high in parts of the neighborhood and is currently working to fix the issue, but we do not expect them to do so anytime soon since the fix requires major changes to the grid.

The XW6048 requires the voltage coming from the grid to be below 130.5V or so. If it goes above that the inverter will stop selling and give a fault. The odd part about the setting is that after the fault, the voltage must stay below 126V (not 130V) for 5 minutes before selling again. As a result our inverter has at times stopped selling at 10am and won't sell again until after 5:30pm.

The contractor claims that the maximum AC1 voltage cannot be easily changed on the inverter. Is the contractor correct? What about the AC1 Hi Volt option in AC settings (page 3-19 of Manual)?

Any help will be much appreciated.

[BB.]

I don't know--But many GT inverter systems include a "service" (password protected/special software) menu where they can "tweak" things like high/low voltage and frequency limits with approval of the utility.

Usually, it is not a big deal (as I understand) to adjust a pole/distribution transformer to move the "grid voltage" up or down a bit to bring the neighborhood into voltage compliance. But if a large/distributed GT Solar installation is exceeding their system design capacity (voltage drop/voltage rise)--Yes it is a big deal for the utility.

There have been reports of a least one new home community that was not allowed to offer GT solar on their new homes unless they paid a lot of money to utility to upgrade their local distribution system. It should be possible to get the PUC to "turn off" the offending large GT system if it is taking the utility power out of regulation.

But--you now are seeing the "down side" of distributed power generation and the lack of support that a utility feels they have to provide for something regulators make them support (GT solar and Net Metering).

You may have to go to the state PUC if you feel the utility is giving you the run-a-round.

Interestingly, when I used to design computer systems, there was not a "national" min/max limit for frequency and voltage that utilities had to guarantee to their customers...

In the end, I decided that 240 VAC (120 VAC) was from 106/212 VAC to 132/264 VAC (roughly +/-10%) (although, since I designed for Japan, I had to go down to 95 VAC because parts of the country had 100 volt mains).

From Wiki:

Following voltage harmonization, electricity supplies within the European Union are now nominally 230 V ± 6% at 50 Hz.^[1] For a transition period (1995–200, countries that had previously used 220 V changed to a narrower asymmetric tolerance range of 230 V +6% −10% and those (like the UK) that had previously used 240 V changed to 230 V +10% −6%.^[2] No change in voltage is required by either system as both 220 V and 240 V fall within the lower 230 V tolerance bands (230 V ±6%). In practice, this allows countries to continue to supply the same voltage (220 or 240 V), at least until existing supply transformers are replaced. Equipment used in these countries is designed to accept any voltage within the specified range.


In the United States^[3] and Canada,^[4] national standards specify that the nominal voltage at the source should be 120 V and allow a range of 114 to 126 V ( RMS) (−5% to +5%). Historically 110, 115 and 117 volts have been used at different times and places in North America. Main power is sometimes spoken of as 110; however, 120 is the nominal voltage.

In 2000, Australia converted to 230 V as the nominal standard with a tolerance of +10% −6%.,^[5] this superseding the old 240 V standard, AS2926-1987.^[6] As in the UK, 240 V is within the allowable limits and "240 volt" is a synonym for mains in Australian and British English.

See if you can get the utility to put in writing what your allowable voltage range is--It sounds like the already agree there are problems, and so far have not pointed at you for being a contributor to the grid voltage problem.

We had somebody here with an Enphase (micro) GT Inverter system were the "factory" came out and reprogrammed the upper limit up a couple of volts (as I recall) on the local GT inverters.

-Bill

[bakunin]

Thanks for your reply Bill,
Yes, it appears there is a software to tweak settings, but it is not easy to obtain. At the moment a friend of a friend is trying to get his hands on one. A power company official himself suggested we change the settings in the inverter. To try to pressure the power company to deal with the situation I have contacted community leaders and the coast guard. I believed the coast guard would at least have some panels that are not selling and that turned out to be the case. Hopefully with the community and coast guard pressure the power company (which is run by the government here in Puerto Rico) will do something about it 'as quickly as possible'. Funny that you mentioned that the power company has "not pointed at you for being a contributor to the grid voltage problem". They actually did, and our incentive application was momentarily in jeopardy. It was explained to them that my 2.8Kw system would not cause any significant changes on the grid's voltage and that they had now basis to reject our application. I think they realized we were willing to take them to court and backed off :)

Currently we are fine tuning the use of the load shaving capability at night to try to make up for some of the power we were not able to sell in the past. Once again thanks for your help,
Robert

[Ralph Day]

"We had somebody here with an Enphase (micro) GT Inverter system were the "factory" came out and reprogrammed the upper limit up a couple of volts (as I recall) on the local GT inverters."

Me.

Enphase reprogrammed all the 52 inverters remotely to the upper voltage limit of 260vac. It didn't take long, but needed the high speed internet connection to the Envoy unit. Anyone worried about security...I shut off my computer during the upgrade, the internet>envoy connection did not include my computer. Enphase is always in contact through my hs connection, the laptop is put in sleep or hibernate when not in use.

Ralph

[solar_dave]

I don't get the stress of opening the Envoy up via a port forwarding setup in the router. I expose my TED to the Internet this way. No other hosts inside are exposed and only the TED appliance on a particular port is visible.

[bakunin]

Contractor claims he is awaiting for the software to change upper limits. He mentioned something about us being able to monitor the inverter online but made it sound like the capability is not available yet.

I've been looking into the advanced settings and I was wondering if changing the AC1 Hi Volt setting at advanced settings-AC settings (see page 3-19 of inverter manual) would help. The default is 132V. It appears the contractor increased it to 135V and I just bumped it up to 140V

[boB]

Aren't you kinda worried about breaking things with too high of AC line voltage ??

132VAC is high enough but 140 VAC ??

boB

[bakunin]

Yes, certainly damaging the electronic appliances is a concern. But there's certain points I left out of the story for the sake of simplicity. For one, we discovered the high voltage issue in April and only now the power utility is claiming "it will deal with it". Another interesting point is that high voltage IS NOT the only problem we are experiencing with the power company. Since January or so, about once a month we have been experiencing "brown outs". These brown outs will sometimes last for hours (although recently they don't last long). The power company is not sure why the brown outs occur. We suspect that they may be related to the coast guard solar system but thanks in part to how infrequent the brown outs are, it is hard to know (or fix) what's going on. During brown outs our voltage is all over the place and I've measured it around 80V. The voltage changes are sometimes so drastic that batteries momentarily crash and our fridge's icemaker starts making popping sounds. In short, we figured, the voltage issues with the power company are already having an effect on our appliances. Oh well, I guess that's the price to live in paradise :)
Anyway, I did increase the upper limit to 140V and the inverter still disconnected today (although I have never seen the AC1 go over 132V on the monitor). On the first chapter of the Xantrex inverter manual it clearly says that anti-islanding settings can be changed if needed. I sent an email to them requesting assistance. They have not answered yet.

[niel]

the utility is responsible to keep the voltage within set limits or they can be held liable for damages. in my area 127vac is the max allowed or 254vac across the so called 240vac wires. the problem with higher voltages is that often higher currents go along with them and you have a 2 fold dilemma facing everything connected to the grid. this higher power is extra heat and will decay the lifespan of items connected to it if they aren't immediately destroyed by the higher voltages. what's worse is the extra power being dissipated you will get billed for so this is insult to injury.

if this were to continue on without resolution then, in addition to a lawsuit, i would be making active efforts to go off of the grid.

[inetdog]

Since January or so, about once a month we have been experiencing "brown outs". These brown outs will sometimes last for hours (although recently they don't last long). The power company is not sure why the brown outs occur. We suspect that they may be related to the coast guard solar system but thanks in part to how infrequent the brown outs are, it is hard to know (or fix) what's going on. During brown outs our voltage is all over the place and I've measured it around 80V. The voltage changes are sometimes so drastic that batteries momentarily crash and our fridge's icemaker starts making popping sounds. In short, we figured, the voltage issues with the power company are already having an effect on our appliances. Oh well, I guess that's the price to live in paradise :)

One predictable effect of the coast guard system is that the load on the utility grid (ranging between positive and negative) can vary drastically and rapidly as clouds pass over the base. If the same amount of power came from a lot of small systems distributed over a large area, the effect would not be as drastic. Possibly the voltage fluctuations which result are causing some other loads somewhere else, such as large motors, to go into a condition in which they are drawing very high current at lower voltages and dragging the grid down until their overcurrent protection shuts them off. Then they try to start again. Or it may be totally unrelated to the base's solar system at all. If it is the explanation and the site which is dragging the system down does not complain, it may be very hard to track down the problem.
You can do your own experiment by measuring the voltage you see on a day with scattered large clouds passing over the base.