now connected to grid, FX not connecting

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now connected to grid, FX not connecting

Postby agasgroth on Thu Apr 25, 2013 3:06 pm

I have been using PV and gen to charge batteries and power my FX inverter.
Since I got connected to grid earlier today, the FX refuses to connect.
There is no facility to sell to grid here.
I have tried both Gen and Grid inputs; neither will accept the connection.
My multimeter shows voltage and frequency well within limits (225V, 50Hz).

I am wanting the FX to keep the batteries charged and provide backup when the grid is down (happens quite often).

I'm sure I am missing something obvious ... but what is it? :???:

thanks.
agasgroth
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Joined: Tue Jun 03, 2008 1:00 pm
Location: Gaborone, Botswana
My RE system: VFX3048E (240VAC export model) with 8no. 12VDC 180Ah deep cycle batteries (two banks of 4), 6no. 175W Solarworld 24V panels and 60A Flexmax controller, hub and mate. Backup is by 5KVA EP6500CX Honda generator. Now also connected to grid (rather unreliable) with 3PH 60A supply.

Re: now connected to grid, FX not connecting

Postby tallgirl on Thu Apr 25, 2013 5:08 pm

Are you sure your inverter is configured to "USE" the grid?
Julie in Texas

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Re: now connected to grid, FX not connecting

Postby agasgroth on Fri Apr 26, 2013 5:31 am

Hi Tallgirl,

I tried it with both settings: USE GRID and USE GEN. In both cases it would try connecting and then give up.
Is the inverter able to tell whether power is from the grid or a generator?
Since I don't want to sell to grid (no provision for that here), should I be using the grid setting?

First priority is to get the inverter to accept power from the grid so that it works as backup.

Second priority will be to set the grid connect time so that it is off when the sun is up and takes power from the sun for the loads that are connected to the inverter (lights, computers, TV, etc.), and only connects to the grid at night.

Third priority will be to have the possibility to use the generator as a backup for when the grid is down for longer periods.

thanks,
Agas
agasgroth
OutBack Whiz
 
Posts: 38
Joined: Tue Jun 03, 2008 1:00 pm
Location: Gaborone, Botswana
My RE system: VFX3048E (240VAC export model) with 8no. 12VDC 180Ah deep cycle batteries (two banks of 4), 6no. 175W Solarworld 24V panels and 60A Flexmax controller, hub and mate. Backup is by 5KVA EP6500CX Honda generator. Now also connected to grid (rather unreliable) with 3PH 60A supply.

Re: now connected to grid, FX not connecting

Postby tallgirl on Fri Apr 26, 2013 6:57 am

It sounds like you've done everything right. At this point, I'd check the inverter for errors or warnings. You can also look at the input voltage using the Mate -- make sure the inverter is "Seeing" the grid voltage correctly.
Julie in Texas

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tallgirl
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Posts: 4329
Joined: Wed Sep 26, 2007 9:59 am
Location: Austin, TX
My RE system: 16 Kyocera KC175GT (2,800 watts DC), MX-60, 2 OutBack GVFX3648, 24 GC2 batteries (6v @ 215AH), 14 Pantheon-based ACPV modules (3,200 watts DC), La Crosse Technologies WS2310 Weather Station, greenLogger Sensors environmental monitor, WattNode watt-hour meter, greenLogger Lite data logger.

Re: now connected to grid, FX not connecting

Postby agasgroth on Sun Apr 28, 2013 4:43 am

Thanks.
Having looked into the problem a little more, there are two things that don't seem right.

1. When the FX is trying to connect, the voltage at the AC input drops way down from 237 to about 160, measured using the Min function on a Fluke 179.
At that moment you can hear quite a loud clunk from the FX. Presumably a relay engaging?
I tried setting the max input current way down to minimum (1.0AAC for Gen and 2.5AAC for grid); made no difference.
I tried both grid and gen input options; made no difference.
I checked all the connections from the grid meter back to the FX and could find nothing loose or dodgy.

2. I used the fluke to check the Mate input voltage readings.
The mate gives me readings that cycle between 222 - 232VAC.
The Fluke reading at the same time is a steady 237VAC +- 1V.

There is no load on the inverter and the batteries are fully charged (hooked up to the panels all day with no work to do! What a life).

Possible solutions?
Clean the contacts on the FX input relay. Can I do this without killing myself (or it)?
Big capacitor somewhere in the system to smooth out the voltage drop?

Agas
agasgroth
OutBack Whiz
 
Posts: 38
Joined: Tue Jun 03, 2008 1:00 pm
Location: Gaborone, Botswana
My RE system: VFX3048E (240VAC export model) with 8no. 12VDC 180Ah deep cycle batteries (two banks of 4), 6no. 175W Solarworld 24V panels and 60A Flexmax controller, hub and mate. Backup is by 5KVA EP6500CX Honda generator. Now also connected to grid (rather unreliable) with 3PH 60A supply.

Re: now connected to grid, FX not connecting

Postby BlackCherry04 on Sun Apr 28, 2013 6:23 am

I don't see where setting the Input down to those levels make much sense. If anything limit the charger Aac or turn it off. The Input will bypass the inverter that way. If the charger is going wide open, it could be pulling the voltage down.

Can you put a load on the Grid Input before the Inverter and see what drop you get ??
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Re: now connected to grid, FX not connecting

Postby tallgirl on Sun Apr 28, 2013 9:48 am

Loading up the connection at the inverter sounds like a way to see what the heck is going on.

There should be a set of bypass breakers which allow the inverter to be completely bypassed. How does the voltage handle that?

Another possibility is mistake in wiring. I don't know how his part of Africa wires things up, but I suspect it's a 230 / 400 Wye configuration and he has one leg of a 3-phase system and then the center of the Wye. If he's swapped earth and neutral, he'd see grid voltage up until he tries to draw power, then earth would float up towards the line based on the resistance between earth and neutral.
Julie in Texas

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tallgirl
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Posts: 4329
Joined: Wed Sep 26, 2007 9:59 am
Location: Austin, TX
My RE system: 16 Kyocera KC175GT (2,800 watts DC), MX-60, 2 OutBack GVFX3648, 24 GC2 batteries (6v @ 215AH), 14 Pantheon-based ACPV modules (3,200 watts DC), La Crosse Technologies WS2310 Weather Station, greenLogger Sensors environmental monitor, WattNode watt-hour meter, greenLogger Lite data logger.

Re: now connected to grid, FX not connecting

Postby agasgroth on Mon Apr 29, 2013 3:03 am

Thanks for the suggestions.
Tallgirl put me on the right track with the discussion about earth and neutral.
Yes, we do have a Y arrangement with three phases and a neutral.
My electrician had wired the board such that all neutrals went through an ELCB, but live to the inverter went direct through a 2 pole circuit breaker.
When the FX was trying to connect it was tripping the ELCB leaving it with a live but floating neutral.
Have now provided it with a functioning neutral and it's working fine.

Sorry for the wild goose chase. It looks so obvious with hindsight!
Again thanks for all the prompt and excellent guidance.

Agas
agasgroth
OutBack Whiz
 
Posts: 38
Joined: Tue Jun 03, 2008 1:00 pm
Location: Gaborone, Botswana
My RE system: VFX3048E (240VAC export model) with 8no. 12VDC 180Ah deep cycle batteries (two banks of 4), 6no. 175W Solarworld 24V panels and 60A Flexmax controller, hub and mate. Backup is by 5KVA EP6500CX Honda generator. Now also connected to grid (rather unreliable) with 3PH 60A supply.

Re: now connected to grid, FX not connecting

Postby BlackCherry04 on Mon Apr 29, 2013 4:50 am

Great, isn't it wonderful to have a smart intelligent woman to lead us out of the darkness ?? You go girl. Unfortunately for me my daughter flunked out of EE and became a cheerleader.
BlackCherry04
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Posts: 87
Joined: Sat Feb 09, 2013 8:50 am
My RE system: Various Different On and Off Grid

Re: now connected to grid, FX not connecting

Postby tallgirl on Mon Apr 29, 2013 5:18 pm

My son is the EE in the family. I just a lowly software engineer with a lot of experience with this sort of equipment.
Julie in Texas

greenMonitor(tm) for OutBack Power Technologies systems from greenHouse Gas and Electric. Learn more now!
User avatar
tallgirl
OutBack Emperor
 
Posts: 4329
Joined: Wed Sep 26, 2007 9:59 am
Location: Austin, TX
My RE system: 16 Kyocera KC175GT (2,800 watts DC), MX-60, 2 OutBack GVFX3648, 24 GC2 batteries (6v @ 215AH), 14 Pantheon-based ACPV modules (3,200 watts DC), La Crosse Technologies WS2310 Weather Station, greenLogger Sensors environmental monitor, WattNode watt-hour meter, greenLogger Lite data logger.


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