A NEW TRANSIENT STABILITY APPROACH APPLIED m MULTI MACHINE POWER SYSTEM

The work aims at developing a new stability approach used to cany out
transient stability studies of a rnultimachine power system when the generator
int~rnsl voltage components E' and E' d are changing with the time. Consider￾ing the generator mechanical damping and the generator control systems ( that
is, the vol~dge regulator and speed governor), each generator is represented by
a 6th-order dynamic model, then the mathenlatical model of the whole system
is derived. Applying the decomposition-aggresdion method, the system is de￾composed by using the triple-wise decomposition. Then avector Lyapunov
function is constructed and used for aggregating the system. An aggregation
matrix is obtained. the stability of which implies asymptotic stability of the sy￾stem equilibrium state.
As an iiiustsative example, the developed stability approach is used to ca-
1ry out transient stability studies of a i'machine, 14-bus power system assumi￾ng a %phase short c~rcnit (with successfill reclosure) near a generator,or a load,
bus. The faulted line is tripped out for clearing the fault. An estimate for the sy￾stem asymptotic stability dom& is determined and used to determine directly
the critical time for reconnectin? the isolated Ime. It is found that the proposed