  In this paper, we present a novel approach to identify the generators and
states responsible for the small-signal stability of power networks. To this
end, the newly developed notion of information transfer between the states of a
dynamical system is used. In particular, using the concept of information
transfer, which characterizes influence between the various states and a linear
combination of states of a dynamical system, we identify the generators and
states which are responsible for causing instability of the power network.
While characterizing influence from state to state, information transfer can
also describe influence from state to modes thereby generalizing the well-known
notion of participation factor while at the same time overcoming some of the
limitations of the participation factor. The developed framework is applied to
study the three bus system identifying various cause of instabilities in the
system. The simulation study is extended to IEEE 39 bus system.
