Abnormally high grid voltage

System · May 2006

I have 2 Fronius IG 4000 inverters that displayed an error code 301 which is excessive voltage. I rebooted them to a state 104 which is a voltage outside it's operating range so it could not fire up in the first place. I measured the voltage and got 270 volts at both inverters which is higher than than the maximum for that inverter. I called southern california edison and opened a trouble ticket. The technician arrived several hours later after I had left, and he read 240 volts with his meter and stated my batteries on my meter may be low and he could not imagine what the problem is. Possible my batteries were low I am sure, but I am un-convinced that is the problem due to the exact same error codes on both inverters stating unacceptable grid voltages.
My question is, have you heard of the grid voltages varying that much throughout the day? The site is 2 hours from me and I hate to drive all the way down there for nothing, thus I am arming myself with any information people have come across. I also have not seen two inverters simultaneously go bad and need replacement. Any insight would be greatly appreciated. The utility company cant seem to make it possible for me to talk to a technician without being onsite and opening a new trouble ticket if you were wondering why I didn't call them, I tried.
Pat

BB. · May 2006

Re: Abnormally high grid voltage

As a reference, up here just south of San Francisco (PG&E), during the day my Xantrex reports ~240vac +/- 2 volts. My home computer UPS is around 115-118 vac.

Do you have an accurate voltage meter to check the voltage yourself? Are the 2 Fronius units interconnected with some control cabling (can you disconnect and see if the problem goes away)? Have you power cycled the inverters (shut AC and DC power off for a couple minutes to force a reboot/error clear)?

The only other issues to check that I can think of... Check that the two AC branch circuit wiring connections are tight and not corroded/overheated (I had a breaker box that got water drips on the terminal connections and got corroded). It probably does not apply, but if there is a neutral wire connected to your Inverters, check that its voltage is very near ground at all times (check to the ground wire/conduit should not be more than 5 volts AC or so).

By the way, Error Code 301, according the the manual I found below, is an AC Over Current and should clear itself without any user interaction.

http://www.fronius.com/worldwide/usa.solarelectronics/downloads/manuals.htm Page 58 of the Manual (pg 66 Adobe)

And Error code 104 is Utility power frequency is out of tolerance (page 57/65).

The error codes from the on-line manual don't seem to agree at all with the ones you have given (I can't even find those listed). So--I might have the wrong manual???

Can you switch off the AC branch breakers for each inverter separately? It sure sounds as if there could be a wiring problem (open or shorted AC branch circuit?)...

Good Luck!
-Bill

niel · May 2006

Re: Abnormally high grid voltage

pat,
it most certainly is possible as most utilities have more than one generating source and when they are switched in or out of the circuit it can spike both the voltage and vary the frequency momentarily. some know this as a surge for the voltage. as to the frequency, if that's the case they aren't a good utility if they allow frequency variations that go too far. unfortunately unless you know somebody with the kind of instruments to measure this stuff you have to try and be there with the utility employee. it's also possible there's fault in your inverters even though the odds are against it.

System2 · May 2006

Re: Abnormally high grid voltage

In case any one was wondering, I put the new one's in and the appeared to work fine. Guess if it happens again I'll worry about it then. The voltage was normal today so who knows. Thanks for the insight.

Abnormally high grid voltage

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