Generators

The generator model covers machine dispatch, voltage regulation, reactive limits, and wind-machine variants.

Dispatch and regulation

An in-service machine at a type 2 bus injects its dispatched active power PG and regulates a voltage to the setpoint VS. The regulated bus is the machine terminal unless IREG names another bus (IREG = 0 selects the terminal). Reactive output is a solution variable bounded by QB and QT.

Reactive limits

At the solution, the controlled voltage equals the setpoint or the reactive output rests at a limit.

Shared regulation

When several machines regulate the same bus, their combined reactive output holds the setpoint and is apportioned among them by RMPCT.

Machines that name a revision 36 droop record follow a reactive characteristic instead of a setpoint. That control is defined on the voltage droop page.

Swing machines

Machines at type 3 buses hold the bus voltage: the magnitude at the machine setpoint VS and the angle at the entered bus VA. The connected machines absorb the active and reactive balance of the system.

Wind machines

The WMOD field selects how reactive capability is derived. With \(\tan\varphi = \sqrt{1 - \mathrm{WPF}^2}\,/\,|\mathrm{WPF}|\):

WMOD	Behavior
0	Conventional machine; QT and QB apply as entered.
1	Reactive limits taken from QT and QB; WPF is not used.
2	Voltage regulation with limits \(\pm\,\lvert PG\rvert \tan\varphi\).
3	Fixed reactive output \(PG \tan\varphi\), signed by the sign of WPF.