2024-08-22
Energy storage plays a crucial role across the entire electricity value chain. Its impact spans power generation, transmission, distribution, and even end-users of electricity. Energy storage provides the most reasonable solution for addressing the challenges of integrating renewable energy, enhancing grid stability, and improving the efficiency of distribution systems. By introducing energy storage into the system, effective demand-side management can be achieved, helping to eliminate the gap between peak and off-peak demand, smooth out loads, make more efficient use of power equipment, reduce electricity costs, and promote the use of renewable energy. Additionally, it serves as an effective means for enhancing system stability, participating in frequency and voltage regulation, and compensating for load fluctuations.
Distributed energy sources, such as solar, wind, and biomass, are typically influenced by external environmental factors like sunlight, temperature, wind, and climate, which makes the generated electricity random and unstable. In scenarios where the microgrid is disconnected from the main grid and operates independently, the output power of distributed energy in the microgrid fluctuates with changes in environmental factors, making it difficult to provide stable output for loads. When applied in microgrids, energy storage systems, controlled by an Energy Management System (EMS), can collaborate with distributed energy sources and the main grid to smooth out the fluctuations of distributed energy, stabilize the output, and improve the local utilization rate of distributed energy. This helps avoid the pressure of long-distance transmission to the main grid and reduces power losses.
Moreover, energy storage systems can continue to provide partial power to critical loads during nighttime or when distributed energy sources are under maintenance, thus reducing downtime.
When the microgrid is connected to the main grid, its power quality must meet national standards, meaning parameters such as power factor, voltage asymmetry, current harmonic distortion, and voltage sags must reach specified values.
As mentioned in the first point, without an energy storage system, the inherent characteristics of the microgrid's energy sources make it difficult to ensure power quality, especially voltage stability. The application of energy storage systems can significantly enhance the power quality within the microgrid. Through the control of the Power Conversion System (PCS) within the energy storage system, it stabilizes power output while regulating the active and reactive power output to the microgrid, addressing voltage sags and dips.
When faced with sudden increases or decreases in the main grid voltage, the energy storage system can provide rapid power buffering, quickly absorbing or supplementing energy, offering active and reactive power support to stabilize voltage fluctuations. Additionally, the energy storage system can provide partial harmonic mitigation functions for the microgrid.
In a microgrid, the energy storage system can store excess energy generated by distributed energy sources during low load periods and release it during peak load times to regulate load demand. As an energy buffer in the microgrid, the energy storage system is indispensable.
While meeting peak load demands, the energy storage system can also reduce the required capacity of generators or transformers.
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