Different from the quasi-static network in the traditional power system, the
dynamic network in the power-electronic-dominated power system should be
considered due to rapid response of converters' controls. In this paper, a
nonlinear differential-algebraic model framework is established with algebraic
equations for dynamic electrical networks and differential equations for the
(source) nodes, by generalizing the Kron reduction. The internal and terminal
voltages of source nodes including converters are chosen as ports of nodes and
networks. Correspondingly, the impact of dynamic network becomes clear, namely,
it serves as a voltage divider and generates the terminal voltage based on the
internal voltage of the sources instantaneously, even when the dynamics of
inductance are included. With this simplest model, the roles of both nodes and
the network become apparent.Simulations verify the proposed model framework in
the modified 9-bus system.Comment: 4 pages, 6 figure