Strings imbalance alert for multi-tracker inverters

Since I’ve already configured my Fronius Symo to push both strings power (Current_DC_String_X_ * Voltage_DC_String_X) would it be possible to setup an alert if( ABS( 0.5 - p1 / (p2+p1) ) > alert_diff) ‘send alert’ ?

  • p1 & p2 is power of individual strings calculated from Current_DC_String_X_ * Voltage_DC_String_X
  • alert_diff is a float e.g. 0.15 (that would be 15% difference in power production between strings)

My arrays are symmetrical and have the same tilt, angle. I’d like PVO to watch for faulty/damaged panels.


As a work around & assuming that p1 and p2 are available as Extended Data what about creating a rule such that:

if ( p1 / ( p1 + p2 ) < 0.4 ) || ( p1 / ( p1 + p2 ) > 0.6 ) v12 = 1 else v12 = 0

You would need to substitute for p1 and p2. You would also need to check for precedence of the operators to make sure the statement is evaluated correctly. As a fudge you could use v2 as the denominator ( Yes that be dividing DC power by AC power but they should still be relatively proportionate.

You could then trigger a Custom Alert if v12 == 1.

Just a thought…

Thanks @grannos, I might be missing something but I seem to run out of free variables to use


Aren’t v1…v6 locked from being modifiable by users? I’ve set unused variables to none to remove them from my charts v3=None&v4=None&v5=None&v6=None
I could use AC_power - p1 to get estimated p2 but this wouldn’t be too precise.

@grannos suggestion would work, but would require a spare parameter to store state.

Without this, the enhancement is to allow alerts to be triggered when the difference between two extended parameters crosses a defined threshold (percentage or absolute).

The other alternative is to use System Performance alerts, but p1 and p2 would need to be posted as v2 to separate systems and the trigger is energy Wh rather than power W.