Revision history [back]

The transmission network is basically a "transfer system" between two systems: the source (generators/plants) and the sink (load centers). PV analysis aims to statically determine the behavior of voltage while transmitting power from the source to load. Most of the time, bus voltage at the vicinity of the sink is depressed whenever power transfer takes place.

You need a subsystem because you want to study a particular system affected by the transfer of power, in this case, you need to check the relationship of power transfer against the bus voltage, hence P-V analysis.