Descriptor State Space Modeling and Oscillation Analysis of Passive Power Networks

With the increasing proportion of renewable energy and power electronic devices in power systems, resonance stability issues have emerged in power networks. This paper focuses on the dynamic characteristics of passive power networks and addresses the resonance stability problem as an excitation issue between the natural oscillation modes of the passive power network and the oscillation frequency of the ideal forcing source. First, based on a descriptor modeling framework, a power network model incorporating both lumped parameter devices and distributed parameter transmission lines is established. Next, through the forced oscillation model of the passive power network, the system steady-state response, natural modes, and the relationship with the forcing source are analytically derived using eigen-analysis. These relationships can be used to locate weak spots in the network and observe harmonic distribution. Finally, case studies are presented to demonstrate the effectiveness of the proposed method in analyzing resonance phenomena in power networks.