ground fail E018

[Shaun Burgess]

hi rob and all .. i have notice this last few weeks if i turn the switch to stop turbine ie join the 3 phases out of turbine.. and then turn the switch back to run the eurora inverter says theres a ground fail and shows errow e018 and inverter turns inself of and then powers up and runs fine the riso = 20.0m omhs and ileak 35ma and low input power .. should i be trying to sort this its runs well thanks sb

[Rob Beckers]

Hi Shaun,

That's a variation I've not seen before...
In general, all the cases of ground faults (E018) that I've looked at turned out to be real, in the sense that there really was a leak to ground someplace that set of the error. Sometimes they were very hard to find.

When exactly does it throw the error? When you switch the stop switch 'on' (ie. short out the 3 phases), and stop the turbine, or when you take the switch off the alternator to start the turbine? If it's the former I wonder if the mechanical violence of suddenly stopping the rotor has anything touching (briefly) causing the ground fault.

-RoB-

[Shaun Burgess]

it does it the second i put turbine to start .. i cant get inverter to power of so it goes to ground fault turns off and then turns on and works perfect

[Rob Beckers]

Hold on a second: With the turbine standing still there's no DC and the inverter should be off at that point. It won't switch on until the RPM gets high enough to generate the starting voltage, Vstart, as programmed into the inverter.

What do you mean "I can't get the inverter to power off"? What's Vstart set at currently? What is the DC voltage you measure on the input when the turbine is stopped (and shorted)? I've seen some cases where for very low Vstart values (50 - 60V) the inverter wouldn't switch off due to stray DC generated by the inverter itself (leaking to the input somehow). In those cases adding a 100 kOhm 5 Watt resistor over the input did the trick.

The ground fault could be an artifact if the inverter really isn't switching off.

-RoB-

[Shaun Burgess]

hi rob i have a 22k 17w resistor across the dc input and inverter will not still power of when theres no wind.. vstart is 70v and first point of curve 70v = 0 watts its the same as you sent me i tryed changing the curve but still never powered of . am starting to think there linked some how thanks sb

[Tom Hoffer]

I have 2 6KW inverters on a Jacobs turbine and have the same problem with one of the inverters. After about 6 months of use the inverter stays on using grid power (turbine not spinning). The back light is also out. I haven't pursued a fix yet, but would like to at some point.

Thanks Tom

[Shaun Burgess]

would this be a problem in the inverter itself . when turbine is stopped the power jumps from around 40v to 73v all the time

[Tom Hoffer]

A 4.7K resistor across the DC did slowly drain down the voltage enough to shut the inverter off. A little more resistance would probably work very well. I checked the amperage draw at the grid side with the turbine stopped. It seems to pull about .6 amps @240 volts or about 145 watts. Much more than I expected. Should have checked sooner. Sorry if I hijacked your thread.

Thanks Tom Hoffer

[Rob Beckers]

Shaun, do you have access to the inverter through the AuroraInstaller program? If so, try setting the time in "TProt UV" lower, something like 60 seconds (it's now probably at 180 or 300 seconds). This is how long the input (DC) voltage has to be below Vstart before the inverter will switch off. Slightly raising Vstart (say to 75V) may help too, without affecting performance with the wind turbine.

It may be (should be) possible to change those parameters through the front panel of the inverter as well. I know Vstart is in there, but don't recall if TProt is. Never tried (I've always used AuroraInstaller). You can easily take a look though.

I've not quite figured out, nor heard a good explanation from Power-One, why these inverters have residual DC on the input when there's nothing coming in. Because they are transformerless, the DC input is actually floating at 240V AC with respect to ground (just that both the positive and negative go up and down at the same time, so there normally is no offset). It must have something to do with the capacitive current set up by the wiring and the AC that's causing the stray DC. Power-One's own PVI-Wind-Interface box (basically a glorified rectifier) has 300 kOhm between the positive and negative, and generally that seems to work well enough.

Tom, a 4.7 kOhm resistor seems too low: At 600V DC it will be dissipating 76 Watt. Unless your turbine never sees high DC voltages I wouldn't go that low. Even at 250V DC it will still dissipate 13 Watt.

Since these inverters are not supposed to 'just stay on' (though all have the stray DC voltage to some extend), you can call Power-One's RMA line at 1-877-261-1374. They'll hook you up with tech support, maybe they'll have an insight as to why this is happening. They may also send out a new inverter to you (since these inverters are still under warranty), but keep in mind that the new inverter will arrive 'empty' and you'll have to save the MPPT curve with AuroraInstaller before shipping back the old one, then install it in the new one.

-RoB-

[Tom Hoffer]

I'll try a 100Kohm resistor and call tech support. My system will run between about 60V to 380V so I will try to minimize any losses. Will post results.

Thanks Tom Hoffer

[Tom Hoffer]

100Kohm 5 watt resister added to DC side of the Aurora 7200 Wind Interface Box did indeed fix the Inverter Power off issue. I found the resister at Mouser Electronics web site.

KOA Speer Metal Oxide Resistors
RSS5 100K 5%

There were about a half dozen similar resisters that would probably have worked just as well.

Thanks for the advice
Tom Hoffer

[Rob Beckers]

Tom, glad to hear that worked!
Shaun, any luck with your inverter since? Did you talk to Power-One?

-RoB-

[Shaun Burgess]

hi rob am talking to my supplier here in ireland .. we think the problem is in the turbine itself .. were going to try pairing up two resister.. sure its worth a try .. is that a world wide number you posted.. thanks sb

[Rob Beckers]

Shaun, didn't know you are in Ireland. The number I posted is for North America only (it's a free number over here). You can try, but I don't think it'll work over there, besides, you need the local customer service since they won't ship out a replacement inverter all the way from North America.

Why do you think it's the turbine? If it's not spinning it can't be generating any voltage to keep the inverter from switching off. That part would be an inverter issue. The ground fault could be the turbine.

-RoB-

[Shaun Burgess]

hi rob . we think the turbine is producing small amounts of power vibrating and holding the inverter voltage up . my supplier here is brillant .. were going to try and two 22r 17w resistors on it and see how it goes . my site is 500ft above sea level and turbine is never realy stopped that much .. but be nice to get in powering off any ideas would be great thanks sb

[Tom Hoffer]

The Aurora inverter has failed to shut down for quite some time now even with the resistor installed. I checked the amperage draw from the grid side and noticed that it cycles with that constant 1 second or so click from the inverter. It pulls a full amp or more at the click then tapers down to about .5 amps I assume the click is the inverter checking synchronization with the grid. Power-One service suggested an inverter replacement so I guess it's time to take care of it.

Tom Hoffer