Variable Input-Output Table - PlantPredict

External Inputs
Weather Data
Site Configuration
Other Time Series Inputs (Optional)
Model Parameters
Module Parameters (Single Diode Model)
Module Temperature Parameters
Inverter Parameters
DC Field & Loss Parameters
Transformer Parameters
AC System Parameters
DC Field Geometry
ESS Parameters (Optional)
Stage 1: Irradiance Variables
Solar Position
Derived Irradiance Parameters
Tracker & Surface Orientation
Plane-of-Array Irradiance Components
Loss/Adjustment Factors
Stage 2: DC Performance Variables
Module Temperature
DC Power Outputs
Stage 3: Inverter Variables
Stage 4: AC & Plant-Level Variables
Array Level
Energy Storage (Optional)
Plant Level

This table provides a comprehensive mapping of variables and parameters in the PlantPredict engine: external inputs, model parameters, key interface variables between models, and final outputs.

External Inputs

Weather Data

Variable	Symbol	Unit	Destination(s)
UTC Date-Time	—	datetime	• Solar Position • Extraterrestrial Irradiance
Global Horizontal Irradiance	$GHI$	W/m²	• Irradiance Quality Check • Decomposition • Transposition
Direct Normal Irradiance	$DNI$	W/m²	• Irradiance Quality Check • Transposition
Diffuse Horizontal Irradiance	$DHI$	W/m²	• Irradiance Quality Check • Transposition
Ambient Temperature	$T_a$	°C	• Solar Position (refraction) • Module Temperature • Inverter Derating
Wind Speed	$v_w$	m/s	Module Temperature
Atmospheric Pressure	$P$	hPa	• Solar Position (refraction) • Air Mass • Decomposition (DIRINT) • Transposition (Perez)
Relative Humidity	$RH$	%	• Decomposition (Reindl) • Spectral Models

Site Configuration

Variable	Symbol	Unit	Destination(s)
Latitude	$\varphi$	degrees	Solar Position
Longitude	$\lambda$	degrees	Solar Position
Altitude	$h$	m	• Solar Position () • Pressure calculation • Inverter Derating
Ground Albedo	$\rho_g$	—	• Transposition • Bifacial Model
Horizon Profile	$h(\gamma)$	degrees	Horizon Shading

Other Time Series Inputs (Optional)

Input	Unit	Used In
Monthly Albedo Factors	—	Transposition
Monthly Soiling Factors	%	Soiling Model
Module Temperature Time Series	°C	Override calculated temperature
Tracking Angle Time Series	degrees	User-defined tracking
Vmpp Time-Series Adjustment	—	Operating Region (V7+)
Impp Time-Series Adjustment	—	Operating Region (V7+)
Inverter Derate Time Series	—	Power derating schedule
Inverter Set Point Time Series	W	Power limiting schedule
LGIA Limit Time Series	MW	POI power clipping

Model Parameters

Module Parameters (Single Diode Model)

Parameter	Symbol	Unit	Used In
Reference Short-Circuit Current	$I_{sc,ref}$	A	STC-to-Operating Adjustment → Single Diode Model
Reference Open-Circuit Voltage	$V_{oc,ref}$	V	STC-to-Operating Adjustment → Single Diode Model
Reference MPP Current	$I_{mp,ref}$	A	STC-to-Operating Adjustment
Reference MPP Voltage	$V_{mp,ref}$	V	STC-to-Operating Adjustment
Reference Power	$P_{ref}$	W	STC-to-Operating Adjustment
Number of Cells in Series	$N_s$	—	• STC-to-Operating Adjustment • Single Diode Model
Temperature Coefficient of Isc	$\alpha_{Isc}$	%/°C	STC-to-Operating Adjustment → Single Diode Model
Temperature Coefficient of Voc	$\beta_{Voc}$	%/°C	STC-to-Operating Adjustment → Single Diode Model
Temperature Coefficient of Pmp	$\gamma_{Pmp}$	%/°C	STC-to-Operating Adjustment
Diode Ideality Factor	$\gamma$	—	• STC-to-Operating Adjustment • Single Diode Model
Reference Series Resistance	$R_{s,ref}$	Ω	STC-to-Operating Adjustment → Single Diode Model
Reference Shunt Resistance	$R_{sh,ref}$	Ω	STC-to-Operating Adjustment → Single Diode Model
Reference Saturation Current	$I_{0,ref}$	A	STC-to-Operating Adjustment → Single Diode Model
Dark Shunt Resistance	$R_{sh,0}$	Ω	STC-to-Operating Adjustment (irradiance) → Single Diode Model
Shunt Resistance Exponent	$R_{sh,exp}$	—	STC-to-Operating Adjustment (irradiance) → Single Diode Model
Bandgap Energy	$E_g$	eV	STC-to-Operating Adjustment (temperature) → Single Diode Model
Recombination Parameter	$d_{i2}/u_t$	—	Single Diode Model (7-parameter)
Built-in Voltage	$V_{bi}$	V	Single Diode Model (7-parameter)

Module Temperature Parameters

Parameter	Symbol	Unit	Model
Conductive Heat Transfer Coefficient	$U_c$	W/(m²·°C)	Heat Balance
Convective Heat Transfer Coefficient	$U_v$	W·s/(m³·°C)	Heat Balance
Cell-to-Module Temperature Difference	$\Delta T_{c-m}$	°C	All temperature models
Sandia Coefficient a	$a$	—	Sandia
Sandia Coefficient b	$b$	s/m	Sandia
NOCT	—	°C	NOCT-SAM

Inverter Parameters

Parameter	Symbol	Unit	Used In
Minimum DC Voltage	$V_{min}$	V	Operating Region
Maximum MPP Voltage	$V_{MPP,max}$	V	Operating Region
Maximum Absolute Voltage	$V_{max}$	V	Operating Region
Minimum DC Power	$P_{min}$	W	Operating Region
AC Rated Power	$P_{AC,rated}$	kVA	Power Limiting
Efficiency Curves	—	—	Efficiency Model
Temperature-kVA Curves	—	—	Temperature Derating

DC Field & Loss Parameters

Parameter	Symbol	Unit	Used In
Module Mismatch Factor	$f_{MM}$	%	DC Power Reduction
Light-Induced Degradation	$f_{LID}$	%	DC Power Reduction
Module Quality Factor	—	%	DC Power Reduction
DC Health/Connections Factor	—	%	DC Power Reduction
DC Wiring Resistance	$R_{s,DC}$	Ω	Added to Series Resistance
Degradation Rate (Linear)	$r_{deg}$	%/year	Annual Degradation
Nonlinear Degradation Rates	$[r_0, r_1, ...]$	%/year	Nonlinear Degradation
Bifaciality Factor	$\phi$	—	Rear-Side Weighting
Structure Shading Factor	—	%	Rear-Side Losses
Backside Mismatch Factor	—	%	Rear-Side Losses

Transformer Parameters

Parameter	Symbol	Unit	Used In
MV Transformer No-Load Loss	$P_{NL}$	%	Transformer Model (quadratic)
MV Transformer Full-Load Loss	$P_{LL}$	%	Transformer Model (quadratic)
MV Transformer Rated Power	$S_{rated}$	kVA	Transformer Model (quadratic)
HV Transformer No-Load Loss	$P_{NL,HV}$	%	HV Transformer Model (quadratic)
HV Transformer Full-Load Loss	$P_{LL,HV}$	%	HV Transformer Model (quadratic)
HV Transformer Rated Power	$S_{rated,HV}$	kVA	HV Transformer Model (quadratic)

AC System Parameters

Parameter	Symbol	Unit	Used In
AC Collection Resistance	$R_{AC}$	Ω	AC Collection (V12+)
AC Collection Loss	—	%	AC Collection (V3-11)
Transmission Line Resistance	$R_{line}$	Ω/km	Transmission Loss
Transmission Line Length	$L_{line}$	km	Transmission Loss
Transmission Line Voltage	$V_{line}$	kV	Transmission Loss
Cooling Load	$P_{cool}$	W	Auxiliary Load
Tracker Motor Load	$P_{tracker}$	W	Auxiliary Load
DAS Load	$P_{DAS}$	W	Auxiliary Load
Availability Factor	$f_{avail}$	%	Availability Loss
Grid Limit (LGIA)	$P_{LGIA}$	MW	POI Power Clipping

DC Field Geometry

Parameter	Symbol	Unit	Used In
Fixed Tilt Angle	$\beta_{fixed}$	degrees	Surface Orientation
Fixed Azimuth Angle	$\gamma_{fixed}$	degrees	Surface Orientation
Tracker Axis Azimuth	$\gamma_{axis}$	degrees	Tracking Algorithm
Maximum Tracker Rotation	$\phi_{max}$	degrees	Tracking Algorithm
Ground Coverage Ratio	$GCR$	—	• Backtracking • Shading Models • Bifacial Model
Module Height	$h_{mod}$	m	Bifacial Model
Row Pitch	$p$	m	• Shading Models • Backtracking • Bifacial Model • GCR calculation
Strings per Inverter	—	—	• Current scaling (parallel) • DC wiring resistance
Modules per String	—	—	• String voltage (Vmp, Voc) • DC wiring resistance

ESS Parameters (Optional)

Parameter	Symbol	Unit	Used In
Battery Capacity	$E_{batt}$	kWh	State-of-Charge Calculation
ESS DC Efficiency	$\eta_{DC,ESS}$	—	Round-Trip Efficiency
ESS Inverter Efficiency	$\eta_{inv,ESS}$	—	DC/AC Conversion Efficiency (Charge/Discharge)
ESS MV Transformer No-Load Loss	$P_{NL,ESS}$	%	ESS Transformer Model (quadratic)
ESS MV Transformer Full-Load Loss	$P_{LL,ESS}$	%	ESS Transformer Model (quadratic)
ESS MV Transformer Capacity	$S_{rated,ESS}$	kVA	ESS Transformer Model (quadratic)
ESS HVAC No-Load Loss	—	%	ESS Auxiliary Load (scales with capacity)
ESS HVAC Full-Load Loss	—	%	ESS Auxiliary Load (scales with power)

Stage 1: Irradiance Variables

Solar Position

Variable	Symbol	Unit	Origin	Destination(s)
Solar	$\theta_z$	degrees	Solar Position Algorithm	• Air Mass • Decomposition • Transposition • Shading
Solar Angle	$\gamma_s$	degrees	Solar Position Algorithm	• Tracking • Shading
Sunrise Time	—	datetime	Solar Position Algorithm	Operational hours
Sunset Time	—	datetime	Solar Position Algorithm	Operational hours
Extraterrestrial DNI	$DNI_{extra}$	W/m²	Extraterrestrial Irradiance	• Clearness Index • Transposition • Decomposition
Clear-Sky GHI	$GHI_{clear}$	W/m²	Bird Clear Sky Model	Spectral corrections
Clear-Sky DNI	$DNI_{clear}$	W/m²	Bird Clear Sky Model	Spectral corrections
Clear-Sky DHI	$DHI_{clear}$	W/m²	Bird Clear Sky Model	Spectral corrections

Derived Irradiance Parameters

Variable	Symbol	Unit	Origin	Destination(s)
Pressure-Corrected	$AM'$	—	Air Mass Model	• Transposition (Perez) • Decomposition (DIRINT) • Spectral Models
	$K_t$	—	Calculated	Decomposition
Precipitable Water	$W$	cm	Calculated from RH/T	Spectral Models
Spectral Shift Factor	$M$	—	Spectral Model	POA Irradiance adjustment

Tracker & Surface Orientation

Variable	Symbol	Unit	Origin	Destination(s)
Tracker Rotation Angle	$\phi_{track}$	degrees	Tracking Algorithm	Surface Orientation
Module Tilt Angle	$\beta$	degrees	• Configuration • Tracking	• Transposition (view factors) • AOI Calculation
Module Azimuth Angle	$\gamma$	degrees	• Configuration • Tracking	AOI Calculation
Angle of Incidence	$\theta$	degrees	Geometry Calculation	• Transposition (beam) • IAM • Shading (2D)

Plane-of-Array Irradiance Components

Variable	Symbol	Unit	Origin	Destination(s)
Pre-Shading POA Irradiance (B/D/G)	—	W/m²	Transposition	Shading Models
Shaded POA Irradiance (B/D/G)	—	W/m²	Shading Models	Soiling
POA Irradiance After Soiling (B/D/G)	—	W/m²	Soiling Model	IAM
POA Irradiance After IAM (B/D/G)	—	W/m²	IAM Model	Effective POA
Effective Front POA Irradiance (B/D/G)	$E_{POA,front}$	W/m²	After All Adjustments	Effective POA Irradiance
Back POA Irradiance (B/D/G)	—	W/m²	Bifacial Model	Effective POA Irradiance
Effective POA Irradiance	$E_{POA,eff}$	W/m²	Front + Back × Bifaciality	Single Diode Model

Loss/Adjustment Factors

Variable	Symbol	Unit	Origin	Applied To
Horizon Shading Factor	$U_{horizon}$	—	Horizon Shading	Beam POA Irradiance
Beam Shading Factor	$U_{shd,B}$	—	Near Shading Models	Beam POA Irradiance
Diffuse Shading Factor	$U_{shd,D}$	—	Diffuse Shading (view factors)	Sky Diffuse POA Irradiance
Ground Shading Factor	$U_{shd,G}$	—	Diffuse Shading (view factors)	Ground POA Irradiance
Electrical Shading Fraction	$f_{elec}$	—	Electrical Shading	Beam POA Irradiance
Soiling Factor	$u_{dirt}$	—	Soiling Model	All POA Irradiance Components
Beam IAM	$f_b$	—	IAM Model	Beam POA Irradiance
Diffuse IAM	$f_d$	—	IAM Model	Sky Diffuse POA Irradiance
Ground IAM	$f_g$	—	IAM Model	Ground POA Irradiance

Stage 2: DC Performance Variables

Module Temperature

Variable	Symbol	Unit	Origin	Destination(s)
Cell Temperature	$T_c$	°C	Temperature Model	Single Diode Model
Module Surface Temperature	$T_m$	°C	Temperature Model	Output

DC Power Outputs

Variable	Symbol	Unit	Origin	Destination(s)
Open-Circuit Voltage	$V_{oc}$	V	Single Diode Model	• Inverter Region Model • Output
Short-Circuit Current	$I_{sc}$	A	STC-to-Operating Adjustment	Output
MPP Voltage	$V_{mp}$	V	Single Diode Model	Inverter Region Model
MPP Current	$I_{mp}$	A	Single Diode Model	Inverter Region Model
MPP Power	$P_{mp}$	W	$V_{mp} \times I_{mp}$	Inverter Region Model

Stage 3: Inverter Variables

Variable	Symbol	Unit	Origin	Destination(s)
Operating Region	—	1–13	Inverter Region Model	• Inverter Control • Output
DC Voltage (after clipping)	$V_{DC}$	V	Inverter Region Model	Inverter Efficiency Model
DC Current (after clipping)	$I_{DC}$	A	Inverter Region Model	Output
DC Power (after clipping)	$P_{DC}$	W	Inverter Region Model	DC Losses Model
Net DC Power	$P_{DC,net}$	W	DC Losses Model	Inverter Efficiency Model
Temperature Derating Factor	$f_{temp}$	—	Temperature Derating	AC Power Limit
Inverter Efficiency	$\eta_{inv}$	—	Inverter Efficiency Model	AC Power
AC Power	$P_{AC}$	W	Inverter Efficiency Model	Inverter Aggregation

Stage 4: AC & Plant-Level Variables

Array Level

Variable	Symbol	Unit	Origin	Destination
Total AC Inverter Power	$P_{AC,inv}$	W	Inverter Aggregation	AC Degradation Model
AC Degradation Loss	$L_{AC,deg}$	W	AC Degradation Model	MV Transformer Model
Auxiliary Loads	$P_{aux}$	W	Cooling + Tracker + DAS	MV Transformer Model
MV Transformer Loss	$L_{MV}$	W	MV Transformer Model	AC Collection Model
Array AC Power	$P_{AC,array}$	W	AC Collection Model	Block Aggregation

Energy Storage (Optional)

Variable	Symbol	Unit	Origin	Destination
Total Power (pre-ESS)	$P_{blocks}$	W	Block Aggregation	ESS Model
State of Charge	$SOC$	%	ESS Model	Charge/Discharge Limits
ESS Charge Power	$P_{charge}$	W	ESS Model	Combined Power
ESS Discharge Power	$P_{discharge}$	W	ESS Model	Combined Power
Combined PV+ESS Power	$P_{POI}$	W	PV - Charge + Discharge	HV Transformer Model

Plant Level

Variable	Symbol	Unit	Origin	Destination
Total Power (pre-HV)	$P_{pre-HV}$	W	Block Aggregation or ESS	HV Transformer Model
HV Transformer Loss	$L_{HV}$	W	HV Transformer Model	Transmission Model
Transmission Line Loss	$L_{trans}$	W	Transmission Model	Availability
Availability Loss	$L_{avail}$	W	Availability	LGIA Clipping
Grid Limit Clipping	$L_{LGIA}$	W	LGIA Clipping	Plant AC Power
Plant AC Power	$P_{AC,plant}$	W	LGIA Clipping	Output

Notes:

B/D/G: Beam, Diffuse, and Ground components are tracked and exported separately.
V12+: Some variables (e.g., AC Collection Resistance) are only available in Version 12 and later.
Aggregation: Power variables aggregate hierarchically: DC Field → Inverter → Array → Block → Plant.
Timestep Loop: All time-series variables are calculated for each timestep, then aggregated to hourly/daily/monthly/annual summaries.

Prediction Model Flow Glossary

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