Create an AC transmission line

A trade object for a passive AC branch: a line whose flow is set by impedance rather than chosen.

Usage

newACLine(
  name,
  commodity,
  from,
  to,
  reactance,
  resistance = NA_real_,
  trade = data.frame(),
  ...
)

Arguments

name

character, name of the object, used in sets.

commodity

character, the transmitted commodity (normally electricity).

from, to

character, the two endpoint regions of the line.

reactance

numeric, series reactance x, strictly positive.

resistance

numeric, series resistance r. Recorded but not used for losses – losses are the fixed fraction teff.

trade

data.frame of further per-route parameters (ava.*, af.*, teff), applied to both directions unless it names src / dst.

...

further arguments passed to newTrade().

Value

Object of class trade.

Details

The constructor differs from newTrade() in three ways, all of which follow from an AC line being a physical two-way branch rather than an arbitrary set of routes:

• it takes the two endpoints as from / to and builds BOTH directed rows, because Kirchhoff's voltage law constrains the net flow;

• reactance is required and is written to both rows, so it is symmetric by construction;

• every other per-route parameter passed through trade is applied to both directions unless it already names src / dst.

A finite reactance is what marks the route as subject to KVL. The object is an ordinary trade in every other respect, and behaves identically to one unless the model is interpolated with kvl = TRUE – so adding reactances to a working model changes nothing until you ask for the physics.

Where several physical circuits have been merged into one modelled line, pass the EQUIVALENT reactance 1/x_eq = sum(1/x_i), not any one circuit's.

See also

newDCLink(), newTrade()

Other class trade: lossTranches(), newDCLink()

Examples

ac <- newACLine("L_W1_W2", commodity = "ELC", from = "W1", to = "W2",
                reactance = 0.02, resistance = 0.001)

# an AC line is bidirectional: both directions are declared as routes
ac@routes
#>   src dst
#> 1  W1  W2
#> 2  W2  W1

# the electrical parameters travel in @misc, where the KVL constraints read them
ac@misc[c("reactance", "resistance")]
#> [[1]]
#> NULL
#> 
#> [[2]]
#> NULL
#>