A Seamless Fault Tolerant Strategy based on Modified Submodule Topology for STATCOM
Yang Liu, Huang Hai, Ma Xinrui, Wang Hanyu · 2025
For fault-tolerant operation of cascaded static synchronous compensators (STATCOMs), this article proposes a seamless fault-tolerant strategy based on a modified standby submodule, aiming to improve the fault tolerance performance and recovery speed after a fault. Traditional cold standby modules have to experience a capacitor voltage charging delay after they are activated, leading to voltage and current distortions during the transition process, as well as capacitor voltage imbalance, which negatively impacts system reliability. To address this issue, a modified standby submodule is proposed in this paper, which uses a parallel dual topology to pre-charge the cold standby submodule, ensuring it can be quickly put into use without extra charging time. This improves transient performance while maintaining capacitor voltage balance. Simulation results show that the proposed modified standby submodule can be smoothly integrated into the system after a fault. The proposed strategy has high reliability and saves the capacitor charging time, effectively combining the advantages of both cold and hot standby modules, providing a seamless fault-tolerant operation solution for STATCOM.