The Static Transfer Switch (STS) is a cabinet-based, cutting-edge switching solution designed for commercial and industrial energy storage systems. Fully compatible with GoodWe ESA 125 kW/261 kWh, it delivers UPS-level on- and off-grid switching in under 20 ms. The STS provides precise control of inverters, enabling seamless transitions between grid-tied and off-grid modes so that, in the event of a grid outage, critical loads are supplied continuously by solar power or batteries and smoothly reconnected to the grid once power is restored. As a versatile cabinet solution, it also supports generator integration and large inductive loads such as heat pumps and motors, ensuring a reliable, flexible and efficient foundation for microgrid energy management.