3.3 Generators

A generator is modeled as a complex power injection at a specific bus. For generator i  , the injection is

 i    i     i
sg = pg + jqg.

Let Sg =  Pg + jQg  be the ng × 1  vector of these generator injections. The MW and MVAr equivalents (before conversion to p.u.) of pi
  g  and qi
 g  are specified in columns PG (2) and QG (3), respectively of row i  of the gen matrix. A sparse nb × ng  generator connection matrix Cg  can be defined such that its      th
(i,j)   element is 1 if generator j  is located at bus i  and 0 otherwise. The nb × 1  vector of all bus injections from generators can then be expressed as

Sg,bus = Cg ⋅ Sg.

A generator with a negative injection can also be used to model a dispatchable load.