The 300MW/600MWh Shared Energy Storage Power Station in Gaoyi County, Shijiazhuang, Hebei Province, is located in Fucun Town and includes a 220kV booster substation together with comprehensive auxiliary facilities. As a strategic investment by Dalian Sanfeng Group in the new energy storage sector, the project marks an important milestone from strategic planning to commercial implementation. It is also one of Hebei Province's flagship projects supporting the development of a resilient and intelligent power grid while accelerating the transition toward a greener, low-carbon energy system.
Developed independently by Guangzhou Zhiguang Electric Technology Co., Ltd. ("Zhiguang Electric Technology"), the Cascaded High-Voltage Power Conversion System (PCS) serves as the project's technological core. Featuring outstanding energy efficiency, strong grid-support capability, and exceptional safety and reliability, it provides a solid foundation for this large-scale energy storage power station and contributes to the high-quality development of the regional new power system.
A Powerful Core for Grid-Forming Energy Storage: Cascaded High-Voltage PCS Unlocks Greater System Value
Technology Insight: A Breakthrough Architecture for High-Voltage PCS
As the energy hub between batteries and the power grid, the Power Conversion System (PCS) is responsible for bidirectional power conversion and grid interaction, directly determining the efficiency, safety, and grid compatibility of an energy storage system.
Conventional low-voltage PCS solutions require step-up transformers to connect to 6–35kV distribution networks. Besides transformer losses, large-scale applications often suffer from increased circulating currents caused by multiple PCS units operating in parallel, resulting in more complex control and weaker grid support capability.
Zhiguang Electric Technology's Cascaded High-Voltage PCS adopts a cascaded multilevel topology, in which multiple power cells are connected in series to directly generate medium-voltage output. This enables transformer-less connection to 6–35kV power grids, fundamentally overcoming the capacity and performance limitations of conventional PCS architectures and representing a key technology direction for high-power energy storage systems.
Delivering Value for Grid-Forming Energy Storage
As renewable energy penetration continues to increase, energy storage is evolving from a conventional peak-shaving resource into a grid-forming asset capable of actively supporting grid stability.
Unlike traditional grid-following energy storage systems that passively synchronize with grid conditions, grid-forming systems emulate the behavior of synchronous generators, actively providing voltage and frequency regulation, virtual inertia, and fault ride-through support. These capabilities are becoming essential for building next-generation power systems.
The technical advantages of the Cascaded High-Voltage PCS align perfectly with the requirements of grid-forming energy storage, delivering value in four key areas.
1. Transformer-less High-Voltage Connection Maximizes Efficiency and Project Returns
The direct medium-voltage connection eliminates transformer losses, enabling PCS conversion efficiency of up to 99%. The cascaded architecture also eliminates circulating currents between battery clusters, significantly improving battery utilization. As a result, more electricity can be delivered to the grid under the same installed capacity, enhancing the lifetime economic performance of the energy storage station.
2. Millisecond-Level Response Strengthens Grid Support
Supporting multiple operating modes including VSG (Virtual Synchronous Generator), VF, and PQ, the PCS provides comprehensive grid-forming capability. It enables one-click black start for hundred-megawatt energy storage plants, automatic power sharing among multiple units, primary frequency regulation, and virtual inertia response. With millisecond-level fault isolation and dispatch response, the system actively stabilizes voltage and frequency fluctuations, helping the grid recover rapidly from disturbances and enabling the energy storage station to function as a reliable "grid stabilizer."
3. Multi-Layer Protection Ensures Long-Term Operational Reliability
The system employs highly insulated, high-reliability power devices together with hierarchical alarm mechanisms and comprehensive fault protection. Coordinated protection and rapid fault isolation prevent single-point failures from affecting overall station operation. Deep integration with a liquid-cooled Battery Management System (BMS) provides multi-level protection for both system-level and cell-level safety, ensuring reliable long-term operation under high-load conditions.
4. Flexible Capacity Expansion for Utility-Scale Deployment
With a single-unit capacity of up to 50MW, the PCS can be flexibly expanded into hundred-megawatt-scale systems. The architecture significantly reduces the number of parallel units required, simplifies station control systems, lowers construction and O&M costs, and supports a wide range of applications including grid-side and renewable generation-side energy storage.
Another Benchmark Project Reinforces Leadership in High-Power Power Electronics
The Shijiazhuang Gaoyi Shared Energy Storage Project represents another benchmark application of Zhiguang Electric Technology's Cascaded High-Voltage PCS in northern China's large-scale shared energy storage market. The project further validates the engineering maturity of the technology in large-capacity, high grid-support applications and reinforces the company's industry-leading position in high-power power electronics innovation.
Looking ahead, Zhiguang Electric Technology will continue advancing cascaded high-voltage technologies by enhancing product performance, reducing deployment costs, and delivering innovative power electronic solutions for more utility-scale energy storage projects. Together with industry partners, the company remains committed to accelerating the development of next-generation power systems and supporting China's carbon peaking and carbon neutrality goals through continuous technological innovation.
