A. Kelinsky; T. Beechner
RCT Systems,
United States
Keywords: solid state transformer (SST), medium voltage (MV) power conversion, wide-bandgap technology, energy storage integration, grid resiliency and survivability, directed energy applications, military shipboard power systems, modular power electronics, power electronic building blocks (PEBBs), shock grade a cabinets, Mil-Std-461 compliance, Mil-Std-1399 compliance, medium-frequency architecture, high-efficiency power conversion, scalable and modular design, mean time between failures (MTBF), mean time to repair (MTTR), cyber/physical security in energy systems, containerized power solutions, advanced grid infrastructure, SiC semiconductor technology
Summary:
The evolving demands of modern energy grids require power conversion systems that can seamlessly integrate diverse energy storage technologies while enhancing grid resiliency, hardening, survivability, and intelligence. RCT Systems is delivering a U.S.-designed and manufactured 1.8 MW Medium Voltage (MV) Solid State Transformer (SST) that converts three-phase 13.8 kVAC distribution voltage to a dedicated and regulated 1 kVDC output, remaining agnostic to the selected energy storage medium. Originally engineered for directed energy (e.g., Radar) and military shipboard applications, this SST utilizes a medium-frequency, wide-bandgap-based architecture, achieving a peak efficiency of over 98%. Furthermore, the SST also meets traditional grid power quality and protection requirements, including a 95 kV Basic Insulation Level (BIL) rating, while significantly reducing both footprint and weight compared to conventional 60-Hz transformers/rectifiers. At the heart of this solution are 200kW-rated Power Electronic Building Blocks (PEBBs). These building blocks can be scaled up to 450 kW for higher power applications, and multiple PEBBs may be paralleled or series-connected to reach 1.8 MW or more. The system leverages a modular approach that can provide N+1 redundancy through additional MV-to-LV power cabinets, ensuring continuous operation despite component failures or fluctuating load conditions. To further extend operational life and enhance Mean Time Between Failures (MTBF), each component is derated where feasible, striking a balance between maximum performance and longevity. Packaged in Shock Grade A cabinets to meet stringent military standards, the SST can be adapted into lighter, weather-sealed enclosures for military and civilian grid deployment. RCT Systems’ demonstrated expertise in containerized power conversion solutions also enables flexible and modular packaging options suited to various space-constrained operating environments. Moreover, the system complies with Mil-Std-461 conducted and radiated electromagnetic interference (EMI) requirements and Mil-Std-1399 power quality requirements, ensuring optimal performance under stringent load profiles, challenging environmental conditions, and complex mission scenarios. These enhanced features can be leveraged to meet critical grid infrastructures, where survivability, reliability, and cyber/physical security are paramount. In addition to its ruggedness, the SST’s design philosophy embraces streamlined maintenance and rapid repair, supporting an aggressive Mean Time to Repair (MTTR) for mission-critical operations. By emphasizing modularity and ease of access, the SST not only reduces the total cost of ownership but also improves uptime in both defense and commercial settings. With its high-efficiency modular architecture, proven SiC semiconductor technology, and robust design, RCT Systems’ 1.8 MW SST delivers a versatile, reliable platform for large-scale energy storage and distribution. This technology pushes the state-of-the-art in power conversion hardware, offering a future-proof, scalable solution capable of withstanding the most demanding defense and commercial energy infrastructure environments. More details can be found at: https://www.rct-systems.com/solid-state-transformer/.