Skip to main content

​
Summary

PV+Storage Integration combines the power flows from the solar PV system and battery energy storage to calculate the total plant output at the point of interconnection. PlantPredict adjusts PV output for battery charging, adds battery discharge to PV output, and applies HV equipment losses to the combined power flow. The integration ensures proper accounting of losses and enforces LGIA capacity limits.

​
Inputs

NameSymbolUnitsDescription
PV MV Transformer OutputPPV,MVP_{PV,MV}WPV power before HV losses
Battery AC Charge at MVPcharge,MVP_{charge,MV}WPower diverted to battery (including MV loss)
Battery AC Discharge at MVPdischarge,MVP_{discharge,MV}WPower from battery (after MV loss)
Interconnect CapacityPPOIP_{POI}WMaximum plant output (LGIA limit)
PV Power After AvailabilityPPV,availP_{PV,avail}WPV output after availability losses

​
Outputs

NameSymbolUnitsDescription
Adjusted PV OutputPPV,adjP_{PV,adj}WPV output after charging diversion
Combined PV+ESS OutputPcombinedP_{combined}WTotal power at MV level
LGIA Limited OutputPPOI,limitedP_{POI,limited}WCombined output limited to LGIA

​
Detailed Description

​
PV Output Adjustment for Charging

When the battery is charging, power is diverted from PV output: PPV,adj=PPV,MV−Pcharge,MVP_{PV,adj} = P_{PV,MV} - P_{charge,MV}

​
LGIA Limiting of Adjusted PV

If both adjusted PV output and original PV output exceed interconnect capacity: PPV,adj,limited=PPOI×PPV,MV,beforePPV,availP_{PV,adj,limited} = P_{POI} \times \frac{P_{PV,MV,before}}{P_{PV,avail}} Otherwise: PPV,adj,limited=PPV,adjP_{PV,adj,limited} = P_{PV,adj}

​
Combined PV+ESS Output

The combined output depends on the operating state: PV positive, battery discharging (negative discharge means tare loss): Pcombined=PPV,adjP_{combined} = P_{PV,adj} PV negative, battery discharging: Pcombined=Pdischarge,MVP_{combined} = P_{discharge,MV} Normal operation: Pcombined=PPV,adj+Pdischarge,MVP_{combined} = P_{PV,adj} + P_{discharge,MV}

​
System Power Flow

The combined PV+ESS output flows through the HV equipment:
  1. Combined output at MV level: PcombinedP_{combined}
  2. HV transformers and transmission lines (same as PV-only)
  3. Availability losses (applied to PV portion only)
  4. Grid limit enforcement

​
ESS Integration with Power Plant Calculation

When ESS is present, the power plant calculation uses the combined output: Pplant,beforeHV=PcombinedP_{plant,before HV} = P_{combined} instead of the sum of block outputs.

​
Charge/Discharge Constraints

Available excess to charge (LGIA Excess algorithm): Pexcess=max⁡(PPV,avail−PPOI,0)P_{excess} = \max(P_{PV,avail} - P_{POI}, 0) Available capacity to discharge: Pdischarge,avail=min⁡(Pdischarge,LGIA,Pdischarge,storage)P_{discharge,avail} = \min(P_{discharge,LGIA}, P_{discharge,storage}) where:
  • Pdischarge,LGIA=max⁡(PPOI−PPV,avail,0)P_{discharge,LGIA} = \max(P_{POI} - P_{PV,avail}, 0)
  • Pdischarge,storage=Pinv−LMV−LHVP_{discharge,storage} = P_{inv} - L_{MV} - L_{HV}