  Synchronization is an essential element in three-phase ac electric power
systems. The large-scale integration of converter-interfaced resources leads to
the power grid transformation from voltage-source-dominated to
voltage-current-source-composite, which also raises new challenges to model and
analyze the system synchronization. In this article, we present the intrinsic
analogy of a power system to a communication system, which is here called
power-communication isomorphism. Based on this isomorphism, we revisit power
system synchronization stability from a communication perspective and thereby
establish a theory that unifies the synchronization dynamics of heterogeneous
power apparatuses. In particular, the proposed theory is used to interpret and
analyze, for example, the different power control speeds of power apparatuses;
the role of network line dynamics in synchronization analysis; and the
synchronization capability of current-source-dominated (e.g.,
grid-following-converter-dominated) grids. The findings are verified on the
IEEE 68-bus test system.
