Fixed transmission loss

What this step does

The row removes a flat share of the exported power on every timestep with export. It represents a loss set in the grid agreement, or the line to a metering point further away. It acts on the grid energy after the HV line.

The math

1. Running total
2. Loss at a timestep

$$E_{after} = E_{before} - E_{row},\qquad E_{row} = \frac{\Delta t}{1000\,P_{DC}}\sum_i L_i \tag{1}$$ $$L_i = f_T\,P_{in,i} \quad (\text{export},\ P_{in,i} > 0) \tag{2}$$

where

Symbol	Meaning	Unit
$E_{before}$	the running total of the loss diagram before this row	kWh/kWp
$E_{after}$	the running total after this row	kWh/kWp
$E_{row}$	the row taken as a loss	kWh/kWp
$\Delta t$	the length of one timestep	hours
$P_{DC}$	the DC nameplate of the system	kWp
$L_i$	the power lost at timestep $i$ over the whole system	W
$f_T$	the fixed transmission loss fraction	—
$P_{in,i}$	the power of the whole system after the HV line at timestep $i$	W

Reading the number

A loss, negative. It is zero on utility and rooftop systems unless a grid agreement sets a fraction; then the row is about that fraction of the grid energy.

API

loss.transmission

Symbols follow the symbol registry.