> ## Documentation Index
> Fetch the complete documentation index at: https://docs.plantpredict.com/llms.txt
> Use this file to discover all available pages before exploring further.

# AC Losses Overview

export const Inverter = () => <Tooltip tip="Power electronics device that sets the operating point on the DC array's I-V curve and converts DC to AC for grid injection.">
    inverter
  </Tooltip>;

export const POI = () => <Tooltip tip="Point of Interconnection: where the plant connects to the utility grid; metering and delivery point for contractual obligations.">
    POI
  </Tooltip>;

export const LGIA = () => <Tooltip tip="Large Generator Interconnection Agreement: contract defining the maximum power export limit at the point of interconnection.">
    LGIA
  </Tooltip>;

export const HV = () => <Tooltip tip="High Voltage: portion of a plant's electrical infrastructure connecting it to the utility grid via step-up transformers and transmission lines.">
    HV
  </Tooltip>;

export const MV = () => <Tooltip tip="Medium Voltage: electrical infrastructure between inverter output and the plant collection point, including step-up transformers and AC cabling.">
    MV
  </Tooltip>;

export const Transformers = () => <Tooltip tip="Devices connecting two AC circuits at different voltages; losses comprise constant no-load (core) and load-dependent (winding) components.">
    transformers
  </Tooltip>;

export const PointOfInterconnection = () => <Tooltip tip="Where the plant connects to the utility grid; metering and delivery point for contractual obligations.">
    point of interconnection
  </Tooltip>;

AC Losses models calculate power dissipation in the AC electrical infrastructure, from <Inverter /> output to the <PointOfInterconnection />.

## Models in This Section

### [Degradation Losses (AC Applied)](degradation_ac_applied)

Time-dependent degradation when applied at the AC level:

* **Linear AC**: Continuous linear degradation applied to inverter AC output
* **Stepped AC**: Annual step-wise degradation applied to inverter AC output
* **LeTID**: Light and Elevated Temperature Induced Degradation (optional)

### [Transformer Loss Model](transformer_loss_model)

Shared quadratic loss model for step-up <Transformers />, used by both the <MV /> transformer (array level) and <HV /> transformers (plant level). The model accounts for constant no-load (core) losses and load-dependent (winding) losses that scale with the square of the loading fraction.

### [Array-Level Aggregation and AC Losses](array_level_losses)

Inverter-to-array aggregation, array-level loss chain, and array-to-block aggregation:

1. Inverter aggregation (sum of inverter outputs × repeater counts)
2. Auxiliary loads (DAS, cooling, tracker motors)
3. MV transformer (uses the shared [Transformer Loss Model](transformer_loss_model))
4. AC collection system (V12+: quadratic I²R model; V3–11: flat percentage)
5. Block aggregation (sum of array outputs × repeater counts)

### [Plant-Level Aggregation and AC Losses](plant_level_losses)

Block-to-plant aggregation and plant-level loss chain to the grid:

1. Block-to-plant aggregation (sum of block outputs × repeater counts)
2. HV equipment — transformers (uses the shared [Transformer Loss Model](transformer_loss_model)) and transmission lines (I²R model), in user-defined order
3. Availability loss (percentage reduction for downtime and curtailment)
4. Grid limit (<LGIA />/<POI /> capacity constraint)

## Calculation Sequence

**Array Level:**

1. Inverter aggregation
2. AC Degradation and LeTID losses (if enabled)
3. Auxiliary loads (DAS, cooling, tracker motors)
4. MV Transformer losses
5. AC Collection System losses
6. Block aggregation

**Plant Level:**

1. Block-to-plant aggregation
2. HV Transformers and Transmission Lines losses (user-defined order)
3. Availability Loss
4. Grid Limit (LGIA)