Research On Control Strategy Of Battery Energy Storage System To Reduce The Effect Of Wind Power On The Grid

Wind power generation is an effective way to solve the problem of energy shortage and environmental pollution. It has an important strategic position in promoting sustainable development of energy, electricity and economic. With increasing penetration of wind energy into the grid, randomness and intermittency characteristics of wind have brought about considerable negative impacts on power system frequency, voltage and stability. Energy storage system has throughput capacity of active and reactive power which can be controlled to regulate fluctuating wind power. How to achieve maximum utilization of wind energy and at the same time minimize its adverse impacts on the grid by using of the energy storage system have become an important research topic.Based on the battery energy storage system, this thesis mainly focuses on control strategies for smoothing wind power fluctuations and supporting system voltage. The main research carried out in this thesis are as follows:1. In order to determine the fluctuations smoothing goals, active power fluctuations characteristics of single wind turbine and frequency response characteristics of the power system are studied. Based on spectral analysis of wind farm output power, the pros and cons of two kinds of wind farm storage configuration structures are compared.2. Conventional strategy based on a fixed time constant low-pass filter has the disadvantages of short battery lifetime and poor long-term smooth effect. Aiming at these problems, an improved control strategy is proposed for the active power control of energy storage system, including a variable time constant filter and state of charge(SOC) feedback control, that can adjust output power of energy storage system in real time based on SOC.3. Reactive power compensation strategy for voltage support is analyzed and studied to make full use of energy storage systems in regulating voltage of wind farms. To not affect active power fluctuations smoothing, maximum reactive capacity of energy storage system is analyzed and used to limit voltage loop output dynamically.4. MATLAB / Simulink simulation is used to verify the effectiveness of strategies proposed in this thesis. The results show that active power fluctuations in wind farms is well smoothed, storage lifetime is extended and voltage of wind farm is effectively maintained, consequently the impact of wind power on the grid is reduced.