Energy storage power stations can store electricity and release it when needed, effectively addressing the imbalance of electricity in time and space. The application of energy storage power station technology permeates all stages of the power system, including generation, transmission, distribution, and consumption. It enables peak shaving and valley filling, smoothing of renewable energy generation fluctuations and tracking plans, efficient system frequency regulation, and increased power supply reliability.
The following are the main components of a typical battery energy storage power station system:
1. Transformers and high-voltage switchgear: These convert the grid voltage (10KV, 6KV, or other voltage levels) supplied by the power grid into the voltage level required by the user's electrical appliances and power consumption (such as 0.4KV).
2. Low-voltage switchgear and control cabinet: used for the control and management of charging, discharging, and power output.
3. Control System: The battery energy storage system is controlled by a programmable logic controller (PLC) and a human-machine interface (HMI). One of the key functions of the PLC system is to control the charging time and rate of the energy storage system. It is integrated with the rest of the system through standardized communication inputs, control signals, and power supply. It can be accessed via dial-up or the Internet. It has multiple layers of defense to restrict access to its different functions and provides customized reporting and alarm functions for remote monitoring.
4. Power Conversion System (PCS): The PCS's function is to charge and discharge the battery, and to provide improved power quality, voltage support, and frequency control to the local power grid. It has a multi-quadrant, dynamic controller (DSP) capable of complex and rapid operations, with dedicated control algorithms, and can switch outputs across the entire range of the device, cyclically switching from full power absorption to full power output. Currently, bidirectional inverters are commonly used.
5. Battery Matrix (Stack): A battery matrix (stack) is composed of several individual cells.
6. Battery energy storage systems can save on fixed equipment investment in the power grid system; improve the utilization rate of power grid equipment; and reduce the operating costs for end users. Energy storage systems can reduce peak energy loads at the distribution end, which will promote the utilization of power grid equipment and meet the needs of end customers. This will improve the power grid load factor.
Battery energy storage systems can act as a buffer between various power sources and stable electricity demand, increasing the generation capacity and legal quality of unstable power sources such as wind and solar power. They can also be used for peak shaving and valley filling for general grid distribution users. During off-peak hours, electricity is stored as DC power in a battery array (pile), and then output at the power frequency (50Hz) to various appliances and power consumers during peak hours. This is equivalent to using electricity from the low-price period during the high-price period; the price difference is the benefit of peak-valley energy storage for electricity savings.
