Network Algebraization and Port Relationship for Power-Electronic-Dominated Power Systems

TL;DR

This paper introduces a nonlinear differential-algebraic model for power-electronic-dominated power systems, highlighting the dynamic network's role as a voltage divider and its impact on terminal voltages, verified through simulations.

Contribution

It generalizes Kron reduction to model dynamic electrical networks with algebraic and differential equations, clarifying the roles of nodes and networks in power-electronic systems.

Findings

Dynamic network acts as a voltage divider

Model accurately predicts terminal voltages

Simulations confirm model validity

Abstract

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.