## External Inputs
### **Weather Data**
| Variable | Symbol | Units | Destination(s) |
| ----------------------------- | ---------- | -------- | ------------------------------------------------------------------------------------------------------------------------------------- |
| UTC Date-Time | — | datetime | • Solar Position
• Extraterrestrial Irradiance
• Sunrise/Sunset Model |
| Global Horizontal Irradiance | $GHI$ | W/m² | • Irradiance Quality Check
• Decomposition
• Transposition
• Ground-Reflected Shading |
| Direct Normal Irradiance | $DNI$ | W/m² | • Irradiance Quality Check
• Transposition
• Ground-Reflected Shading |
| Diffuse Horizontal Irradiance | $DHI$ | W/m² | • Irradiance Quality Check
• Transposition
• Ground-Reflected Shading |
| Ambient Air Temperature | $T_a$ | °C | • Solar Position (refraction)
• Module Temperature
• Inverter Derating
• Decomposition (Reindl)
• Spectral Models |
| Wind Speed | $v_w$ | m/s | Module Temperature |
| Atmospheric Pressure | $P$ | hPa | • Solar Position (refraction)
• Air Mass
• Decomposition (DIRINT)
• Bird Clear Sky |
| Relative Humidity | $RH$ | % | • Decomposition (Reindl)
• Spectral Models |
| Wind Gust Speed | $v_{gust}$ | m/s | Wind Stow |
| Dewpoint Temperature | $T_d$ | °C | Spectral Models |
| Plane-of-Array Irradiance | $G_{POA}$ | W/m² | POAI Decomposition (when Frontside POAI enabled) |
### **Site Configuration**
| Variable | Symbol | Units | Destination(s) |
| ------------------- | ------------------------- | ------- | ------------------------------------------------------------------------------------ |
| Latitude | $\varphi$ | degrees | Solar Position |
| Longitude | $\lambda$ | degrees | Solar Position |
| Altitude | $h$ | m | • Solar Position (
)
• Pressure calculation
• Inverter Derating |
| Albedo | $\rho$ | — | • Transposition
• Bifacial Model
• Bird Clear Sky |
| Standard UTC Offset | $\text{UTC}_{\text{off}}$ | hours | Sunrise/Sunset Model |
| Horizon Profile | $(\gamma_i, e_i)$ | degrees | Horizon Shading |
### **Other Time Series Inputs (Optional)**
| Input | Units | Used In | |
| ------------------------------ | ---------------- | ----------------------- | ------------------------------- |
| Monthly Albedo Factors | — | Transposition | |
| Monthly Soiling Factors | % | Soiling Model | |
| Module Temperature Time Series | $T_{m,measured}$ | °C | Override calculated temperature |
| Tracking Angle Time Series | degrees | User-defined tracking | |
| Vmpp Time-Series Adjustment | $\Delta V_{MPP}$ | % | Operating Region (V7+) |
| Impp Time-Series Adjustment | $\Delta I_{MPP}$ | % | 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 | Units | Used In |
| --------------------------------------- | ---------------------------------------- | ------- | ----------------------------------------------------------------------------- |
| Reference Short-Circuit Current | $I_{sc,ref}$ | A | Parameter Translation
→ Single Diode Model |
| Reference Power | $P_{mp,ref}$ | W | Parameter Translation / DC Wiring Resistance |
| Number of Cells in Series | $N_c$ | — | • Parameter Translation
• Single Diode Model |
| Temperature Coefficient of Isc | $\alpha_{I_{sc}}$ | %/°C | Parameter Translation
→ Single Diode Model |
| Diode Ideality Factor | $\gamma_{ref}$ | — | Parameter Translation |
| Temp. Coeff. of Ideality Factor | $\alpha_{\gamma}$ | 1/°C | Parameter Translation |
| Ideality Factor Polynomial Coefficients | $a_\gamma, b_\gamma, c_\gamma, d_\gamma$ | various | Parameter Translation |
| Reference Series Resistance | $R_{s,ref}$ | Ω | Parameter Translation
→ Single Diode Model |
| Reference Shunt Resistance | $R_{sh,ref}$ | Ω | Parameter Translation
→ Single Diode Model |
| Reference Saturation Current | $I_{0,ref}$ | A | Parameter Translation
→ Single Diode Model |
| Dark Shunt Resistance | $R_{sh,0}$ | Ω | Parameter Translation (irradiance)
→ Single Diode Model |
| Shunt Resistance Exponent | $R_{sh,exp}$ | — | Parameter Translation (irradiance)
→ Single Diode Model |
| Bandgap Energy | $E_g$ | eV | Parameter Translation (temperature)
→ Single Diode Model |
| Recombination Parameter | $d_i^2/\mu\tau$ | V | Single Diode Model (7-parameter) |
| Built-in Voltage | $V_{bi}$ | V | Single Diode Model (7-parameter) |
| Reference Irradiance | $G_{ref}$ | W/m² | • Parameter Translation
• Temperature Models
• DC Wiring Resistance |
| Reference Temperature | $T_{ref}$ | °C | • Parameter Translation
• DC Wiring Resistance |
### **Module Temperature Parameters**
| Parameter | Symbol | Units | Model |
| ------------------------------------- | ---------------- | -------------- | ----------------------- |
| Conductive Heat Transfer Coefficient | $u_c$ | W/m²·K | Heat Balance |
| Convective Heat Transfer Coefficient | $u_v$ | W/m²·K per m/s | Heat Balance |
| Cell-to-Module Temperature Difference | $\Delta T_{c-m}$ | °C | All temperature models |
| Absorption Coefficient | $\alpha_T$ | — | Heat Balance |
| Module STC Efficiency | $\eta_{STC}$ | — | Heat Balance / NOCT-SAM |
| Conductive Coefficient | $a$ | — | Sandia |
| Convective Coefficient | $b$ | s/m | Sandia |
| Transmittance-Absorptance | $\tau\alpha$ | — | NOCT-SAM |
| NOCT | $NOCT$ | °C | NOCT-SAM |
### **Inverter Parameters**
| Parameter | Symbol | Units | Used In |
| ------------------------ | ------------------------ | ------- | ------------------------------------- |
| Minimum MPP Voltage | $V_{MPP,min}$ | 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 | $\eta_{V_j}(P_{AC,i})$ | kW, % | Efficiency Model |
| Temperature-kVA Curves | $P_{AC,derate,h_k}(T_j)$ | °C, kVA | Temperature Derating |
| AC Power Setpoint | $P_{AC,set}$ | kVA | Temperature Derating / Power Limiting |
### **DC Field & Loss Parameters**
| Parameter | Symbol | Units | Used In |
| ----------------------------- | ----------------- | -------- | ---------------------------------------------------- |
| Module Mismatch Coefficient | $f_{MM}$ | % | DC Power Reduction |
| Light-Induced Degradation | $f_{LID}$ | % | DC Power Reduction |
| Module Quality Factor | $f_{MQ}$ | % | DC Power Reduction |
| DC Health Factor | $f_{DCH}$ | % | DC Power Reduction |
| DC Wiring Loss Percentage | $L_{wire}$ | % | DC Wiring Resistance |
| DC Wiring Resistance | $R_{DC,module}$ | Ω | Added to Series Resistance |
| Degradation Rate (Linear) | $r_{deg}$ | %/year | Annual Degradation |
| Nonlinear Degradation Rates | $[r_0, r_1, ...]$ | %/year | Nonlinear Degradation |
| LeTID Annual Rates | $[l_0, l_1, ...]$ | %/year | LeTID Degradation |
| Bifaciality Factor | $\phi$ | — | Rear-Side Weighting |
| Structure Shading Factor | $f_{str}$ | % | Rear-Side Losses |
| Backside Mismatch Factor | $f_{MM,rear}$ | % | Rear-Side Losses |
| Module Transmission Factor | $\tau$ | — | Rear Irradiance (bifacial) |
| SunSolve Transmission Gain | $f_T$ | — | Rear Irradiance (bifacial, SunSolve-calibrated mode) |
| Field-Level Wiring Resistance | $R_{DC,field}$ | Ω | Loss Reporting |
| Energization Date | $t_0$ | datetime | DC Degradation Model |
### **Transformer Parameters**
| Parameter | Symbol | Units | Used In |
| ----------------------------- | -------------- | ----- | -------------------------------- |
| MV Transformer No-Load Loss | $L_{NL,MV}$ | % | MV Transformer Model (quadratic) |
| MV Transformer Full-Load Loss | $L_{FL,MV}$ | % | MV Transformer Model (quadratic) |
| MV Transformer Rated Power | $P_{MV,rated}$ | kVA | Transformer Model (quadratic) |
| HV Transformer No-Load Loss | $L_{NL,HV}$ | % | HV Transformer Model (quadratic) |
| HV Transformer Full-Load Loss | $L_{FL,HV}$ | % | HV Transformer Model (quadratic) |
| HV Transformer Rated Power | $P_{HV,rated}$ | MVA | HV Transformer Model (quadratic) |
### **AC System Parameters**
| Parameter | Symbol | Units | Used In |
| ----------------------------- | ----------- | --------- | -------------------------------------------------- |
| AC Collection Loss | $f_{coll}$ | % | Array-Level Losses |
| Transmission Line Resistance | $R_{line}$ | Ω/1000 ft | Transmission Loss |
| Transmission Line Length | $\ell_t$ | km | Transmission Loss |
| Transformer High-Side Voltage | $V_{HS}$ | kV | Transmission Loss |
| Conductors per Phase | $N_{cond}$ | — | Transmission Loss |
| Inverter Design Derate | $d$ | — | Power Factor / Transmission Loss |
| Cooling Load | $L_{cool}$ | W | Auxiliary Load |
| Tracker Motor Load | $L_{track}$ | W | Auxiliary Load |
| DAS Load | $L_{DAS}$ | W | Auxiliary Load |
| Availability Loss Factor | $f_{avail}$ | % | • Availability Loss
• Power Flow (ESS re-run) |
| Grid Limit (LGIA) | $P_{POI}$ | MW | POI Power Clipping |
### **DC Field Geometry**
| Parameter | Symbol | Units | 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 |
| Tracker Axis Tilt | $\beta_{axis}$ | degrees | Tracking Algorithm |
| Minimum Rotation Limit | $\alpha_{min}$ | degrees | Tracking Algorithm |
| Maximum Rotation Limit | $\alpha_{max}$ | degrees | Tracking Algorithm |
| Nighttime Stow Angle | $\alpha_{stow,night}$ | degrees | Tracking Algorithm |
| Wind Stow Angle | $\alpha_{stow,wind}$ | degrees | Wind Stow |
| Ground Slope | $\beta_g$ | degrees | • Backtracking
• Shading Models |
| Ground Slope Azimuth | $\gamma_g$ | degrees | • Backtracking
• Shading Models |
| Ground Coverage Ratio | $GCR$ | — | • Backtracking
• Shading Models
• Bifacial Model |
| Post Height | $h_{post}$ | m | Bifacial Model |
| Row-to-Row Pitch | $p$ | m | • Shading Models
• Backtracking
• Bifacial Model
• GCR calculation |
| Collector Width | $\ell_m$ | m | • Shading Models
• Backtracking
• Bifacial Model
• GCR calculation |
| Row Length | $L$ | m | Row-to-Row Beam Shading |
| Bay Pile Heights | $(h_{S,i}, h_{N,i})$ | m | Terrain-Aware Backtracking |
| East Neighbor Pile Heights | $(h'_{E,S,i}, h'_{E,N,i})$ | m | Terrain-Aware Backtracking |
| West Neighbor Pile Heights | $(h'_{W,S,i}, h'_{W,N,i})$ | m | Terrain-Aware Backtracking |
| Bay Length | $L_b$ | m | Row-to-Row Beam Shading |
| Bay Spacing | $s_b$ | m | Row-to-Row Beam Shading |
| Bays Per Row | $N_b$ | — | Row-to-Row Beam Shading |
| Number of Rows | $N_{rows}$ | — | Row-to-Row Beam Shading |
| Cross-Axis Slope | $\beta_c$ | degrees | Sky Diffuse Shading |
| DC Field Repeater Count | $n_{rep,i}$ | — | DC Field Aggregation |
| Inverter Repeater Count | $n_{rep,inv}$ | — | Array-Level Losses |
| Array Repeater Count | $n_{rep,array}$ | — | • Array-Level Losses
• Plant-Level Losses |
| Block Repeater Count | $n_{rep,block}$ | — | Plant-Level Losses |
| Strings per Inverter | $N_{p,i}$ | — | • Current scaling (parallel)
• DC wiring resistance |
| Modules per String | $N_{s,i}$ | — | • String voltage (Vmp, Voc)
• DC wiring resistance |
### **Tracking Control Parameters**
| Parameter | Symbol | Units | Used In |
| ------------------- | --------------- | --------- | ----------------------- |
| Hesitation Factor | $f_h$ | — | Irradiance Optimization |
| Rotation Speed | $\omega$ | degrees/s | Irradiance Optimization |
| Wind Stow Threshold | $v_{threshold}$ | m/s | Wind Stow |
| Time Interval | $\Delta t$ | seconds | Irradiance Optimization |
| Time Interval | $\delta t$ | minutes | Battery Model |
### **Spectral Correction Parameters**
| Parameter | Symbol | Units | Used In |
| ------------------------- | ------------------ | ----- | -------------------------------------- |
| Sandia Polynomial Factors | $[a_0, ..., a_4]$ | — | Spectral Correction (Sandia) |
| Two-Variable Coefficients | $[b_0, ..., b_5]$ | — | Spectral Correction (Two-Variable) |
| Monthly Spectral Loss | $L_{spectr,month}$ | % | Spectral Correction (Monthly Override) |
### **Electrical Shading Parameters**
| Parameter | Symbol | Units | Used In |
| -------------------------- | ------ | ----- | ------------------------------------------ |
| Fractional Shading Percent | $f$ | % | Electrical Shading (Fractional) |
| Number of Module Rows | $M$ | — | Electrical Shading (Fractional, pre-V12) |
| Number of Bay Fractions | $N$ | — | Electrical Shading (Step-Fractional, V12+) |
### **IAM Parameters**
| Parameter | Symbol | Units | Used In |
| ------------------------------ | --------------------- | ---------- | --------------------------------------- |
| ASHRAE IAM Parameter | $b_0$ | — | IAM (ASHRAE) / Ground-Reflected Shading |
| Sandia IAM Polynomial Factors | $[b_0, ..., b_5]$ | degree⁻ⁱ | IAM (Sandia) |
| Refractive Index | $n$ | — | IAM (Physical) |
| ARC Refractive Index | $n_{ARC}$ | — | IAM (Physical) |
| Absorption Coefficient (glass) | $\alpha_{abs}$ | m⁻¹ | IAM (Physical) |
| Glass Thickness | $L_{glass}$ | m | IAM (Physical) |
| IAM Factor Pairs | $\{(\theta_i, f_i)\}$ | degrees, — | IAM (Tabular) |
### **ESS Parameters (Optional)**
| Parameter | Symbol | Units | Used In |
| ---------------------------------- | ------------------ | ------- | ---------------------------------------------- |
| Nameplate Energy Capacity | $E_{nom}$ | MWh | State-of-Charge Calculation |
| Usable Capacity Factor | $f_{usable}$ | — | State-of-Charge Calculation |
| Initial Round-Trip DC Efficiency | $\eta_{RT,init}$ | % | Round-Trip Efficiency |
| Capacity Cycle Degradation Rate | $d_{E,cycle}$ | %/cycle | Battery Degradation |
| Capacity Calendar Degradation Rate | $d_{E,year}$ | %/year | Battery Degradation |
| RTE Cycle Degradation Rate | $d_{\eta,cycle}$ | %/cycle | Battery Degradation |
| RTE Calendar Degradation Rate | $d_{\eta,year}$ | %/year | Battery Degradation |
| ESS Inverter Efficiency | $\eta_{inv}$ | % | DC/AC Conversion Efficiency (Charge/Discharge) |
| ESS Inverter Rated AC Power | $P_{AC,rated,ESS}$ | MW | Charge & Discharge Limits |
| ESS MV Transformer No-Load Loss | $L_{NL,ESS}$ | % | ESS Transformer Model (quadratic) |
| ESS MV Transformer Full-Load Loss | $L_{FL,ESS}$ | % | ESS Transformer Model (quadratic) |
| ESS MV Transformer Rating | $P_{MV,rated,ESS}$ | MVA | ESS Transformer Model (quadratic) |
| Custom Inverter Capacity Fraction | $f_{cap}$ | — | Charge & Discharge Limits (Custom Dispatch) |
| Dispatch Table | $D_{m,h}$ | boolean | Dispatch Algorithms |
| Custom Dispatch Time Series | $C_t$ | — | Dispatch Algorithms |
***
## Stage 1: Irradiance Variables
### **Solar Position, Extraterrestrial, and Clear-Sky Irradiance**
| Variable | Symbol | Units | Origin | Destination(s) |
| ----------------------------------------- | ------------- | -------- | --------------------------- | ----------------------------------------------------------------------------------------- |
| Solar
| $\theta_z$ | degrees | Solar Position Algorithm | • Air Mass
• Decomposition
• Transposition
• Shading
• Bird Clear Sky |
| Solar
Angle | $\gamma_s$ | degrees | Solar Position Algorithm | • Tracking
• Shading |
| Sunrise Time | $t_{rise}$ | datetime | Sunrise/Sunset Model | • Operational hours
• Horizon Shading |
| Sunset Time | $t_{set}$ | datetime | Sunrise/Sunset Model | • Operational hours
• Horizon Shading |
| Extraterrestrial Direct Normal Irradiance | $DNI_{extra}$ | W/m² | Extraterrestrial Irradiance | • Transposition
• Decomposition
• Bird Clear Sky |
| Clear-Sky Global Horizontal Irradiance | $GHI_{clear}$ | W/m² | Bird Clear Sky Model | Decomposition (DIRINT) |
| Clear-Sky Direct Normal Irradiance | $DNI_{clear}$ | W/m² | Bird Clear Sky Model | Decomposition (DIRINT) |
| Clear-Sky Diffuse Horizontal Irradiance | $DHI_{clear}$ | W/m² | Bird Clear Sky Model | Decomposition (DIRINT) |
### **Derived Irradiance Parameters**
| Variable | Symbol | Units | Origin | Destination(s) |
| --------------------------------- | ------------ | ----- | ------------------------------------ | ----------------------------------------------- |
| Relative
| $AM$ | — | Air Mass Model | Transposition (Perez) |
| Pressure-Corrected
| $AM'$ | — | Air Mass Model | • Decomposition (DIRINT)
• Spectral Models |
| Precipitable Water | $W$ | cm | Weather file or calculated from RH/T | Spectral Models |
| Spectral Correction Factor | $U_{spectr}$ | — | Spectral Model | POA Irradiance adjustment |
### **Tracker & Surface Orientation**
| Variable | Symbol | Units | Origin | Destination(s) |
| ----------------------- | ----------------- | ------- | ------------------------------- | ----------------------------------------------------------- |
| Tracker Rotation Angle | $\alpha$ | degrees | True Tracking | • Backtracking
• Irradiance Optimization |
| Backtracking Angle | $\alpha_B$ | degrees | Standard Backtracking | Terrain-Aware Backtracking |
| Terrain-Corrected Angle | $\alpha_{TABT,i}$ | degrees | Terrain-Aware Backtracking | Surface Orientation |
| Optimized Tracker Angle | $\alpha_{opt}$ | degrees | Irradiance Optimization | Wind Stow / Surface Orientation |
| Commanded Tracker Angle | $\alpha_{final}$ | degrees | Wind Stow | Surface Orientation |
| Module Tilt Angle | $\beta_m$ | degrees | • Configuration
• Tracking | • Transposition (view factors)
• AOI Calculation |
| Module Azimuth Angle | $\gamma_m$ | degrees | • Configuration
• Tracking | AOI Calculation |
| Angle of Incidence | $\theta_{AOI}$ | degrees | Geometry Calculation | • Transposition (beam)
• IAM
• Row-to-row shading |
### **Plane-of-Array Irradiance Components**
| Variable | Symbol | Units | Origin | Destination(s) |
| -------------------------------------- | ------------------- | ----- | ---------------------------- | ----------------------------------------------------------- |
| Transposition Factor (Global) | $TF_{POA}$ | — | 3D Transposition | POA Irradiance adjustment |
| Transposition Factor (Beam) | $TF_{beam}$ | — | 3D Transposition | POA Irradiance adjustment |
| Transposition Factor (Sky Diffuse) | $TF_{sky}$ | — | 3D Transposition | POA Irradiance adjustment |
| Transposition Factor (Ground) | $TF_{ground}$ | — | 3D Transposition | POA Irradiance adjustment |
| 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 |
| Front POA Irradiance | $G_{POA,front}$ | W/m² | Transposition (sum of B/D/G) | • NOCT-SAM Temperature Model
• Irradiance Optimization |
| Effective Front POA Irradiance (B/D/G) | $G_{POA,front,eff}$ | W/m² | After All Adjustments | Effective POA Irradiance |
| Back POA Irradiance (B/D/G) | — | W/m² | Bifacial Model | Effective POA Irradiance |
| Effective POA Irradiance | $G_{POA,tot,eff}$ | W/m² | Front + Back × Bifaciality | Single Diode Model |
### **Loss/Adjustment Factors**
| Variable | Symbol | Units | 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 |
| Sky Diffuse Shading Factor | $U_{shd,D}$ | — | Diffuse Shading (view factors) | Sky Diffuse POA Irradiance |
| Ground Shading Factor | $U_{shd,G}$ | — | Ground-Reflected Shading | Ground POA Irradiance |
| Electrical Shading Factor | $U_{shd,B,elec}$ | — | Electrical Shading | Beam POA Irradiance |
| Soiling Factor | $U_{soil}$ | — | Soiling Model | All POA Irradiance Components |
| Beam IAM Factor | $U_{IAM,B}$ | — | IAM Model | Beam POA Irradiance |
| Sky Diffuse IAM Factor | $U_{IAM,D}$ | — | IAM Model | Sky Diffuse POA Irradiance |
| Ground Diffuse IAM Factor | $U_{IAM,G}$ | — | IAM Model | Ground POA Irradiance |
***
## Stage 2: DC Performance Variables
### **Module Temperature**
| Variable | Symbol | Units | Origin | Destination(s) |
| -------------------------- | ------ | ----- | ----------------- | ------------------ |
| Cell Temperature | $T_c$ | °C | Temperature Model | Single Diode Model |
| Module Surface Temperature | $T_m$ | °C | Temperature Model | Output |
### **DC System Losses & Parameter Translation**
| Variable | Symbol | Units | Origin | Destination(s) |
| --------------------------- | ------------------ | ----- | --------------------- | --------------------- |
| Scaled Effective Irradiance | $G'_{POA,tot,eff}$ | W/m² | DC System Losses | Parameter Translation |
| Series Resistance | $R_s$ | Ω | Parameter Translation | Single Diode Model |
| Shunt Resistance | $R_{sh}$ | Ω | Parameter Translation | Single Diode Model |
| Diode Ideality Factor | $\gamma$ | — | Parameter Translation | Single Diode Model |
| Saturation Current | $I_0$ | A | Parameter Translation | Single Diode Model |
| Photocurrent | $I_{ph}$ | A | Parameter Translation | Single Diode Model |
### **DC Power Outputs**
| Variable | Symbol | Units | Origin | Destination(s) |
| --------------------- | -------- | ----- | ---------------------- | ------------------------------------- |
| Open-Circuit Voltage | $V_{oc}$ | V | Single Diode Model | • Inverter Region Model
• Output |
| Short-Circuit Current | $I_{sc}$ | A | Parameter Translation | 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 | Units | Origin | Destination(s) |
| ------------------------------- | ---------------- | ----- | ------------------------- | ------------------------- |
| DC Open-Circuit Voltage | $V_{DC,oc}$ | V | DC Field Aggregation | Inverter Region Model |
| DC Voltage (after clipping) | $V_{DC}$ | V | Inverter Region Model | Inverter Efficiency Model |
| DC Operating Power | $P_{DC}$ | W | Inverter Region Model | Inverter Efficiency Model |
| Degraded DC Power | $P_{DC,deg}$ | W | DC Degradation Model | Inverter Region Model |
| DC Degradation Loss | $L_{deg}$ | W | DC Degradation Model | Output |
| DC LeTID Loss | $L_{LeTID}$ | W | DC Degradation Model | Output |
| Temperature-Corrected Max Power | $P_{AC,derated}$ | W | Temperature Derating | Inverter Region Model |
| Inverter Efficiency | $\eta$ | — | Inverter Efficiency Model | AC Power |
| Inverter AC Power | $P_{AC,inv}$ | W | Inverter Efficiency Model | Inverter Aggregation |
***
## Stage 4: AC & Plant-Level Variables
### **Array Level**
| Variable | Symbol | Units | Origin | Destination |
| ------------------- | -------------- | ----- | ----------------------- | -------------------- |
| Array AC Power | $P_{AC,array}$ | W | Inverter Aggregation | AC Degradation Model |
| Degraded AC Power | $P_{AC,deg}$ | W | AC Degradation Model | Auxiliary Loads |
| AC Degradation Loss | $L_{deg}$ | W | AC Degradation Model | Output |
| LeTID Loss | $L_{LeTID}$ | W | LeTID Model | Output |
| Auxiliary Loads | $P_{aux}$ | W | Cooling + Tracker + DAS | MV Transformer Model |
| MV Transformer Loss | $L_{MV,trans}$ | W | MV Transformer Model | Output |
| Block Power | $P_{block}$ | W | Array-Level Losses | Plant-Level Losses |
### **Energy Storage (Optional)**
| Variable | Symbol | Units | Origin | Destination |
| --------------------------- | --------------- | ------- | ---------------------------- | ------------------------------------------------------ |
| PV MV Transformer Output | $P_{MV}$ | W | Array-Level Losses | • Charge & Discharge Limits
• Power Flow |
| PV Power After Availability | $P_{avail}$ | W | Plant-Level Losses (PV-only) | • Charge & Discharge Limits
• Dispatch Algorithms |
| HV Equipment Losses | $L_{HV}$ | W | Plant-Level Losses (PV-only) | Charge & Discharge Limits |
| Charge Flag | $F_c$ | boolean | Dispatch Algorithms | Battery Model |
| Discharge Flag | $F_d$ | boolean | Dispatch Algorithms | Battery Model |
| Available Charge Power | $P_{charge}$ | W | Charge & Discharge Limits | Battery Model |
| Available Discharge Power | $P_{discharge}$ | W | Charge & Discharge Limits | Battery Model |
| State of Charge | $SOC$ | Wh | Battery Model | Battery Model (feedback) / Output |
| Battery DC Power | $P_{DC,batt}$ | W | Battery Model | Power Flow |
| DC RTE Loss | $L_{\eta}$ | W | Battery Model | Output |
| Combined PV+ESS Power | $P_{combined}$ | W | Power Flow | HV Transformer Model (re-run) |
### **Plant Level**
| Variable | Symbol | Units | Origin | Destination |
| ------------------------ | ------------ | ----- | ------------------------------------- | ------------------ |
| Plant Power | $P_{plant}$ | W | Block Aggregation (or $P_{combined}$) | HV Equipment |
| HV Transformer Loss | $L_{HV}$ | W | HV Transformer Model | Transmission Model |
| Transmission Line Loss | $L_{line}$ | W | Transmission Model | Availability |
| Power After HV Equipment | $P_{HV,out}$ | W | HV Equipment Chain | Availability |
| Power After Availability | $P_{avail}$ | W | Availability Model | LGIA Clipping |
| Grid Limit Clipping | $L_{LGIA}$ | W | LGIA Clipping | Output |
| Grid Power | $P_{grid}$ | W | LGIA Clipping | Output |