Modeling of MMC-based STATCOM with embedded energy storage for the simulation of electromagnetic transients

The Delta-connected STATCOM is regarded as the most advantageous topology for STATCOMs based on the Modular Multilevel Converter (MMC) technology. Embedding energy storage devices into the MMCs has gained significant research interest in recent years. This paper focuses on modeling of MMC-based Delta-STATCOMs with embedded energy storage. A flexible modeling approach is proposed, which allows easy interfacing of various converter models with various energy storage device models. Four commonly used types of MMC models are applied to STATCOM modeling: detailed, detailed equivalent, arm equivalent, and average value. Supercapacitors and batteries are used as energy storage devices. Dynamic performances of the models are compared in transient simulation cases using EMTP.