First the feeder skeleton is built by creating segments of overhead and/or underground lines.
To these are added transformers and voltage regulators which are associated with the segments and are placed at either end of a segment.
Capacitors can be added at any node (segment endpoint) in the feeder and may be "on" or "off".
Loads can be modeled at a
segment mid-point (distributed load) or at any node (spot load).
