Schneider XW Pro Enhanced Grid Support: Sell and Peak Load Shave

[GRMRC]

See system below in signature.
Currently running Enhanced Grid Support with Sell. So far so good.
Want to turn on Load Shave too so I only export excess power and not import it.
Grid Shave can be 0 to 48 amps.
Watt node in the BCS has grid sell showing as positive amps and grid import showing as negative amps.
PG&E shows my imports and exports the same as Insight so all good there.
The problem is how to you Load Shave greater than x amps when imported power shows up with negative amps.

Thoughts?

 

[BentleyJ]

The inverters have their own internal power flow sensors. Having the BCS-Watt Node in the system should not over-ride the current values being measured by the inverter to regulate Peak Load Shave. I could be wrong but that would be a major firmware issue if Peak Load Shave cannot be used with a BCS.

 

[GRMRC]

The Grid Export and Grid Import is handled by the Watt Node in the BCS. The XW Pros handle battery charge and discharge as well as power flow to the house loads. MPPTs handle the power delivered from solar. The issue with the BCS and the way single line drawing that Schneider supplies is that Grid Import comes IN on AC1 and Grid Export goes OUT on AC1. Watt Node handles Import as Negative Current Flow so therefore Grid Export is Positive Current Flow. How Schneider expects Load Shaves Amp > than a negative numbers is beyond me.

One other point to be aware with Grid Sell Amps. That setting is on the DC side of the XW Pro. In reality it determines how much AC power the inverter will produce. That AC power is consumed by the loads first and any remaining gets exported. Obviously if loads exceed AC produced the sell goes to zero and the needed extra power is imported from grid.

 

[BentleyJ]

Is your system wired for whole home back up on the main panel per the BCS diagram with NO connections to the inverter output (load side)?
Where are the CT's located. They should be on the mains upstream from the main breaker.

If PLS is enabled and Load Shave Amps is set to 0 and the Watt Node reads positive values for imported power, I'm not seeing the problem.

The Load Shave Amps setting is the amount of current the inverter will allow to be imported from the grid before it tries to support the load. If its set at 0 then the inverter will use battery (and solar when available) to carry 100% the loads so imported power is 0 or close to it. If imported power starts to go up the Watt Node will show increasing positive values and ramp up the inverter voltage to pick up more of the load.

Am I missing something?

 

[GRMRC]

Is your system wired for whole home back up on the main panel per the BCS diagram with NO connections to the inverter output (load side)?
Where are the CT's located. They should be on the mains upstream from the main breaker.

If PLS is enabled and Load Shave Amps is set to 0 and the Watt Node reads positive values for imported power, I'm not seeing the problem.

The Load Shave Amps setting is the amount of current the inverter will allow to be imported from the grid before it tries to support the load. If its set at 0 then the inverter will use battery (and solar when available) to carry 100% the loads so imported power is 0 or close to it. If imported power starts to go up the Watt Node will show increasing positive values and ramp up the inverter voltage to pick up more of the load.

Am I missing something?

Whole home backup. No connections on the inverter load side. AC1 only. Watt node reads import as negative and export as positive. Qty of export and imports match with PG&E. I agree with you that if imports were positive there shouldn’t be a problem but alas imports are currently negative.

 

[GRMRC]

Whole home backup. No connections on the inverter load side. AC1 only. Watt node reads import as negative and export as positive. Qty of export and imports match with PG&E. I agree with you that if imports were positive there shouldn’t be a problem but alas imports are currently negative.

Schneider confirmed that watt node operates with Grid Export as Positive and Grid Import as Negative.
So while grid selling Schneider can handle bidirectional current flow.
It appears when load shaving ANY current on the watt node will get “shaved”. Even if you were selling.

So, the bottom line it’s Grid Sell OR Load Shave. Can’t handle them as a logical AND.
So it’s Start Time and End Time for Grid Sell should be set which lets you set the Load Shave Start and End Time for the other remaining hours in the day.
Of course that is nowhere in the documentation.

 

[400bird]

One other point to be aware with Grid Sell Amps. That setting is on the DC side of the XW Pro. In reality it determines how much AC power the inverter will produce. That AC power is consumed by the loads first and any remaining gets exported. Obviously if loads exceed AC produced the sell goes to zero and the needed extra power is imported from grid.

"Maximum Export (Sell) Sell Amps"
on mine is definitely AC amps. It only goes up to 27 amps and does a out 6kW when I have it set to 27. At 1 amp, it exports about 200-250 watts.

What software version are you on?

 

[GoldenGateCanyon]

In the Sept 2022 version of the XW Pro Multi-unit Design Guide, I see that Load Shave is explicitly not functional with BCS. Looks like Schneider designed it that way.

 

[Cataract2]

Schneider confirmed that watt node operates with Grid Export as Positive and Grid Import as Negative.
So while grid selling Schneider can handle bidirectional current flow.
It appears when load shaving ANY current on the watt node will get “shaved”. Even if you were selling.

So, the bottom line it’s Grid Sell OR Load Shave. Can’t handle them as a logical AND.
So it’s Start Time and End Time for Grid Sell should be set which lets you set the Load Shave Start and End Time for the other remaining hours in the day.
Of course that is nowhere in the documentation.

Curious to see your settings for this. I'm playing around with mine and currently keep the Smart Energy Manager turned on because otherwise my system will jump to 13kW export discharging the battery trying to grid support the damn neighborhood. Guessing I'm missing something here.

 

[GRMRC]

Curious to see your settings for this. I'm playing around with mine and currently keep the Smart Energy Manager turned on because otherwise my system will jump to 13kW export discharging the battery trying to grid support the damn neighborhood. Guessing I'm missing something here.

What % SOC are you using to allow enhanced grid support? What are your grid sell amps set to? Given 13kW export you must must be running
master/slave XW Pros.

 

[Cataract2]

What % SOC are you using to allow enhanced grid support? What are your grid sell amps set to? Given 13kW export you must must be running
master/slave XW Pros.

%SOC changes, but currently it's 30%. Grid sell amps is 27A for the three XW Pros. Yes.

 

[400bird]

Want to turn on Load Shave too so I only export excess power and not import it.

I don't think this is how Peak Load Shave works.

Grid Shave can be 0 to 48 amps.

What this setting does is try to cover any load in the house over your selection. For example, if you set it to 10 amps, the grid will cover 9 amps of load. Once you hit 11, the grid will cover the first 10, then the XW supports anything over 10, in this example 1 amp.

The problem is how to you Load Shave greater than x amps when imported power shows up with negative amps.

If you want the XW to cover you loads turn on Grid Support and turn off Peak Load Shave. That is unless you have a reason to let the grid power some portion of your base loads.

 

[GRMRC]

%SOC changes, but currently it's 30%. Grid sell amps is 27A for the three XW Pros. Yes.

And you wonder why so much power is being sold to the grid? Why 30% SOC for enhanced grid support? Why dump so much power to the grid when your batteries are so low SOC?

 

[Cataract2]

And you wonder why so much power is being sold to the grid? Why 30% SOC for enhanced grid support? Why dump so much power to the grid when your batteries are so low SOC?

I actually adjust the SOC up and down. Batteries are used to cover TOU high tariff rates and with winter I figure I'll not hit 100%. To get grid coverage with the BCS I adjust the SOC to make the inverters begin to use the excess. The BCS negates Peak Load Shave at least according to the docs.