Is there ANY way to get XW+ inverter to do grid bypass during a fault??

aj164

I'm sure this has been discussed here before, but I can't find it.  Maybe it needs to be revisited.  WHY IN THE WORLD does the XW system shut down all power when there is an inverter fault???  Is there a setting I'm missing?  Is there ANY WAY to make it simply pass the grid through during a fault (and maybe save a customer's food from rotting in the refrigerators/freezers)??? 

I got a call yesterday morning (6:30AM) from a customer.  His backed up circuits were off.  The XW had an F.02 fault (AC output voltage high).  OK - why would it not simply use its internal relays to take itself out of the circuit and allow grid bypass?   It does this EVERY NIGHT when there's no solar input (the two dashes "--" in the display).  If the XW is capable of detecting all kinds of faults, including stuck relays, shouldn't it be capable of determining when it's OK to fault with grid bypass enabled? 

We're installing these back-up systems to give our customers peace of mind that their most important loads (refrigerators, freezers, medical equipment, computers, etc) will remain powered when the grid goes down.  We're selling INCREASED reliability.  However, if you think about it, we've actually done the OPPOSITE!  If the XW system drops all power to the output circuits (including simple grid bypass) every time it has a problem, then the customer's power reliability on the backed up circuits is only as good as the reliability of the XW system.  In other words, they don't get the reliability of the grid _plus_ what the XW can add; They only get the dependability of the XW.  

So it seems like we may have mislead all of our grid-tied customers.  Historically, the grid is 99.9% reliable here.  It rarely goes down, and when it does, it's just a minute or less.  They would be better off NOT having battery backup if the battery backup system can take a dump and shut down the grid bypass in the process! 

I sure hope I am missing something, and there is a setting somewhere to fix this issue.    (sigh)

Dave Angelini

You are missing the AC bypass switching built into every Outback and Schneider power distribution panel. The customer should know how to use this until the fault is solved.

You also should not be getting power disconnects in a well designed power system but battery back-up can have issues and the user needs to know what is happening. XW & Radians log most all faults and warnings. High AC voltage is a fault to protect the loads. Why is this happening is what needs to be solved. This is not normal and probably a fault with the grid. You could widen the AC1 parameters but something is not right with the grid. 

 Last point from me is the reason grid inverters make most sense is they do not have this layer of complexity that just is not for everyone. In many cases a genset and grid inverter are often the way to go.

Pretty easy for me as I do not have to deal with this in my Offgrid business

paulcheung

aj164 said:

I'm sure this has been discussed here before, but I can't find it.  Maybe it needs to be revisited.  WHY IN THE WORLD does the XW system shut down all power when there is an inverter fault???  Is there a setting I'm missing?  Is there ANY WAY to make it simply pass the grid through during a fault (and maybe save a customer's food from rotting in the refrigerators/freezers)??? 

I got a call yesterday morning (6:30AM) from a customer.  His backed up circuits were off.  The XW had an F.02 fault (AC output voltage high).  OK - why would it not simply use its internal relays to take itself out of the circuit and allow grid bypass?   It does this EVERY NIGHT when there's no solar input (the two dashes "--" in the display).  If the XW is capable of detecting all kinds of faults, including stuck relays, shouldn't it be capable of determining when it's OK to fault with grid bypass enabled? 

We're installing these back-up systems to give our customers peace of mind that their most important loads (refrigerators, freezers, medical equipment, computers, etc) will remain powered when the grid goes down.  We're selling INCREASED reliability.  However, if you think about it, we've actually done the OPPOSITE!  If the XW system drops all power to the output circuits (including simple grid bypass) every time it has a problem, then the customer's power reliability on the backed up circuits is only as good as the reliability of the XW system.  In other words, they don't get the reliability of the grid _plus_ what the XW can add; They only get the dependability of the XW.  

So it seems like we may have mislead all of our grid-tied customers.  Historically, the grid is 99.9% reliable here.  It rarely goes down, and when it does, it's just a minute or less.  They would be better off NOT having battery backup if the battery backup system can take a dump and shut down the grid bypass in the process! 

I sure hope I am missing something, and there is a setting somewhere to fix this issue.    (sigh)

Hi I like to know, Is the inverter shut down the power as the grid has fault or it supply the load from battery power until the battery bank are drained? is it only one XW+ behave like this or more than one does the same thing? I have a XW+ can't do load shave again but it usually does. the other features are still working.

If you sure the load can tolerate the high grid AC voltage, there is an easy fix with this situation. just put an automatic transfer switch on the loads and the two source of power make the inverter power primary. when the inverter shut down it transfer to the grid. That is what I have in my system.

best wishes

aj164

The grid voltage is fine.  The XW is the problem.  One of the two XW inverters is having some internal issue and throwing erroneous faults, while the other inverter works just fine.  The bad XW will eventually fault (may take hours, may take days) and shut down the whole shebang, including grid power.  

My question was simple:  Why did the XW engineers not program the device to keep the grid connected when the XW faults?  What is going on electrically in a good XW inverter when it shows "--" in the display?  If the answer is that the grid is connected to AC out, and the inverter output board is disconnected from the circuit, then it stands to reason that it is physically possible for the unit to do its own "bypass" internally, giving the loads a better chance to stay running.  

The manual grid bypass isn't helpful when the customer isn't home, or when the XW system is installed at a vacation cabin/home that isn't occupied all the time.   

-Adam

mike95490

When my system was installed, the main panel has a transfer interlock bracket over 2 breakers to provide XW inverter bypass. if the inverter faults, it must "safe" itself or it can fail the UL testing,  Much easier to safe to OFF than to hope enough logic remains to switch a bypass relay,

Dave Angelini

As Mike said and remember they did not just design this for your particular requirements but a host of others also.
The Outback Radians will do the same thing in a multi unit system. The fail safe is to fault and shut down. This alerts the owner that they need service or replacement.

Not many cabins or vacation homes with multi unit XW's either

aj164

Dave Angelini said:
...

The Outback Radians will do the same thing in a multi unit system. The fail safe is to fault and shut down. 
...

I notice you specifically wrote, "...in a multi-unit system."  Does this mean a system with a single XW would allow grid bypass during certain faults?  

mike95490 said:

...Much easier to safe to OFF than to hope enough logic remains to switch a bypass relay,
...

Mike, I notice in the XW inverter Owner's Guide, the auxiliary relay can be programmed to trigger on "Fault".  So there evidently is a mechanism through which the inverter can do something halfway intelligent during a fault.  

OK - so if they couldn't make the XW simply click its relays to perform a grid bypass internally under a fault (in order to pass UL), then how about an external bypass relay?  I can use the Aux Relay output to trigger an external bypass.   It's a PIA and it'll cost more, but at least it's better than the current situation.  

Cheers,
Adam

Dave Angelini

Wire to your hearts content! Lucky that offgrid folks have enough gray matter to flip the existing inverter bypass switch.
Insight2 and combox would email you in a fault and you could check and remote program the site with Insight2.