In today's society, the development of energy storage technology has become the key to solving the problem of intermittent power generation from renewable energy sources. In particular, high-voltage direct-hanging energy storage technology, as a new type of MW battery energy storage solution, is gradually coming into people's vision. The basic principle of this technology is that through the energy storage converter (Power Control System, referred to as PCS) directly access the high voltage level (3kV and above) grid, eliminating the necessary transformer link in the traditional energy storage system.
The core of the high-voltage direct-mounted energy storage system is an energy storage unit called H-Cell. This kind of unit can convert the direct current of multiple battery packs into alternating current through single-phase PCS, and realize high voltage output by series, and finally achieve the effect of matching the voltage of the grid. It is worth mentioning that while improving efficiency, this technology also focuses on reducing harmonic pollution caused by the power grid, ensuring the stability and security of the power grid.
Classification of large-scale energy storage systems
From an economic point of view, the overall efficiency of the high-voltage direct-mounted energy storage system is improved by about 2% due to the elimination of transformers and filtering devices. For large-scale energy storage systems, this means significant savings in operating costs over the life cycle, while increasing operating benefits. Taking a system with a cycle life of 6000 cycles and a capacity of 2MW/2MWh as an example, this small increase in overall efficiency can save or add hundreds of MWh of power over its entire life cycle.
High-voltage direct-mounted energy storage systems also show innovation in battery management. Traditional MW-level energy storage systems mostly rely on passive equalization technology, which has limitations in the face of large-capacity batteries. In contrast, the power balance between batteries is effectively achieved through the active balancing control strategy. This not only extends the battery life, but also optimizes the operating efficiency of the system.
100 MW cascading direct mounted energy storage system with highly reliable layered control strategy. This system not only has the world's highest direct-mounted voltage (35kV), but also the largest capacity (100MW) high-voltage direct-mounted energy storage solution. It can quickly respond to grid dispatching commands in a very short time, that is, 5 milliseconds, and achieve active and reactive power regulation from 0 to 100% between 50 milliseconds and 100 milliseconds, showing excellent performance and efficiency.
High voltage direct hanging energy storage technology with its unique design principle and efficient operation mechanism, in the field of new energy shows broad application prospects and huge development potential. With the continuous maturity of the technology and the increase of application cases, we have reason to believe that this technology will play a more important role in the future energy structure adjustment and green development.