In this article:
Overview
This calculation combines all relevant available information to create a “smart event” for reduced AC capacity. It creates three types of events:
Curtailment
Inverter Module Outage, and
Reduced AC Capacity
The calculation runs once overnight on all inverters of a given PV site. It requires “day of” historical data.
Calculation logic
Open logic
APM event open: Inverter Down, Clipping, or Curtailment | Inverter.EffectiveIrradiance.Calculated > low_irradiance_threshold | InverterModule.ActivePower.Mean | Inverter.ActivePowerPowerFlatlineFlag = 1 | (Inverter.ActivePowerPowerFlatlineFlag = 1 ) OR (Inverter.DCVoltageDeviationFlag = 1 AND clear sample) for open_window intervals | Peer Comparison of Inverter.PerformanceIndex.Calculated at PPC level | AI Insights event open | Event to open |
|---|---|---|---|---|---|---|---|
no | yes | at least one flatlined | majority of inverters on PPC flatlined | - | majority of inverters and given inverter have low Performance Index | - | Curtailment |
no | yes | missing | - | yes | majority of inverters and given inverter have low Performance Index | - | Curtailment |
no | yes | at least one flatlined at 0 | - | - | given inverter has Performance Index below median of all inverters | Curtailment event not open | Inverter Module Outage |
no | yes | missing | - | yes | minority of inverters and given inverter have low Performance Index | Curtailment and Inverter Module Outage events not open | Reduced AC Capacity |
Close logic
APM event open: Inverter Down, Clipping, or Curtailment | Inverter.EffectiveIrradiance.Calculated > low_irradiance_threshold | open condition for _ not met within close_window intervals | AI Insights event open | Event to close |
|---|---|---|---|---|
yes, Curtailment | - | - | - | Curtailment |
no | yes | Curtailment | - | Curtailment |
no | yes | Inverter Module Outage or Reduced AC Capacity | - | Inverter Module Outage |
no | yes | Reduced AC Capacity | - | Reduced AC Capacity |
no | - | - | Curtailment or Inverter Module Outage events open | Reduced AC Capacity |
Inputs
Signals
Segment Apcode | Mloc Apcode | CalcType | CalcPeriod | MType |
|---|---|---|---|---|
Inverter | ActivePowerFlatlineFlag | Calculated | siteTR | Flag |
Inverter | ClippingFlag | Calculated | siteTR | Flag |
Inverter | CurtailmentFlag | Calculated | siteTR | Flag |
Inverter | DCVoltageDeviationFlag | Calculated | siteTR | Flag |
Inverter | EffectiveIrradiance | Calculated | siteTR | Irradiance |
Inverter | InverterDownFlag | Calculated | siteTR | Flag |
Inverter | PerformanceIndex | Calculated | siteTR | Percent |
Inverter | ReducedACCapacityEventFlag | Calculated | siteTR | Flag |
Inverter | CurtailmentEventFlag | Calculated | siteTR | Flag |
Inverter | InverterModuleOutageEventFlag | Calculated | siteTR | Flag |
InverterModule | ActivePower | Mean | siteTR | Power |
IrradianceSensor | POAIrradiance | ClearSamplesFlag | siteTR | Irradiance |
Entity Properties
Segment Apcode | EP Apcode | Notes |
|---|---|---|
Inverter | PPCID | Only exists for sites with multiple PPCs. |
Subarray | PlaneOfArrayId |
|
IrradianceSensor | PlaneOfArrayId |
|
IrradianceSensor | SensorType |
|
Configuration parameters
Parameter | Value | Notes |
LOW_IRRADIANCE_THRESHOLD | 200 |
|
CLOSE_WINDOW | 4 |
|
MAJORITY_INVERTERS_PROPORTION | 0.5 | proportion to determine if majority vs. minority inverters have low performance index |
MIN_INTERVALS_FLATLINED_OR_DEVIATED | 2 | open window |
PI_THRESHOLD | 90.0 | performance index threshold to determine if it is low |
Outputs - Signals
Segment Apcode | Mloc Apcode | CalcType | CalcPeriod | MType | Unit |
|---|---|---|---|---|---|
Inverter | CurtailmentEventFlag | Calculated | siteTR | Flag | - |
Inverter | InverterModuleOutageEventFlag | Calculated | siteTR | Flag | - |
Inverter | ReducedACCapacityEventFlag | Calculated | siteTR | Flag | - |
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