Fast Excitation Control System Design and AC Loss Evaluation for HTS Synchronous Condenser in Renewable Energy Systems

Distributed dynamic synchronous condensers (DSCs) offer fast response and high overload capacity, making them widely used for reactive power support and inertia response in distributed renewable energy systems (DRES). A 10 Mvar-class high temperature superconducting (HTS) DSC is currently under development. To meet the grid-code requirements for fast dynamic response and enhance the transient reactive support of the HTS DSC, a fast DC excitation power topology and control method are proposed to improve its performance. A Simulink model, based on the IEEE standard four-machine two-area test system, is established to simulate five typical operating scenarios: no-load excitation, rated excitation, dynamic excitation, forced excitation, and de-excitation. The simulation results successfully verify the dynamic reactive power support capability of the 10-Mvar HTS DSC. Additionally, a 30-kW prototype of the DC exci-tation power supply is developed to experimentally validate the performance of the fast dynamic excitation system. Finally, AC losses under these five operating scenarios are calculated using a finite element method (FEM) based on the T-A formulation.