Recently, the National Energy Administration officially announced the third batch of major technical equipment lists for the first (set) in the energy sector. The “100MW HV Series-Connected Direct-Hanging Energy Storage System”, jointly proposed by Tsinghua University, China Three Gorges Corporation Limited, China Power International Development Limited, and Xi’an Xidian Electric Power System Co., Ltd., has successfully made it to the list.

Large-scale energy storage systems address the randomness, volatility, and intermittency of new energy generation, complementing the time scales of wind and solar energy storage. This enhances the controllability and dispatchability of new energy generation, serving as a crucial technological means to improve the large-scale integration and active support capabilities for new energy.

In response to issues associated with existing high-capacity energy storage systems, such as harmonic oscillations, low energy conversion efficiency, and high demands on battery management systems, a collaborative effort between the Department of Electrical Engineering and Applied Electronics (EEA) of Tsinghua University, the DC Research Center of Energy Internet Innovation Research Institute of Tsinghua University, and the DC Research Office of Tsinghua Sichuan Energy Internet Research Institute, along with China Three Gorges Corporation Limited, China Power International Development Limited, and Xi’an Xidian Electric Power System Co., Ltd., formed the Tsinghua team. They conducted joint research to achieve technological breakthroughs in four areas: “power devices — battery modules — power conversion — system integration”, comprehensively overcoming the design challenges of the 100MW high-voltage series-connected direct-hanging energy storage system. They established a coordinated control and balance control technology system for the three levels of “battery — inverter — system”, using domestically developed IGCT-Plus devices to develop the world’s first set of 100MW HV series-connected direct-hanging energy storage systems. This system currently holds the record for the largest single-machine capacity internationally, filling a gap in both domestic and international markets.

Topology of the 100MW HV series-connected direct-hanging energy storage system

The topology of the hundred-megawatt high-voltage series-connected direct-hanging energy storage system integrates energy storage and reactive power compensation functions, enabling four-quadrant operation. It can provide both 100MW active regulation output and up to 140MVar reactive support, offering inertia support to the new energy power system. The system can respond rapidly to grid dispatch instructions within milliseconds, achieving 0 to 100% adjustment of active and reactive power within tens of milliseconds. Its international leading technical parameters effectively address stability issues in large-scale new energy stations after grid incorporation.

Power conversion compartment of the high-voltage series-connected direct-hanging energy storage system

Currently, the project unit is developing a 50MW/100MWh high-voltage series-connected direct-hanging energy storage system and a 100MW/200MWh high-voltage series-connected direct-hanging energy storage system. Once completed, this project will become the world’s largest single-machine capacity direct-hanging energy storage system and the first set of hundred-megawatt high-voltage series-connected direct-hanging energy storage systems internationally.

In the future, with the implementation of the “dual carbon” goals and the continuous advancement of new type power system construction, the “100MW HV Series-Connected Direct-Hanging Energy Storage System” will have broad application prospects in large-scale new energy development and other scenarios. The implementation of this project has formulated a “replicable and scalable” large-scale energy storage development plan, holding significant importance for building new type power systems and improving the grid’s capacity to accept renewable energy.