###### Abstract  
Aiming at the low-frequency oscillation problem of high-proportion wind power and energy storage connected to the power system, this paper establishes a system small signal model according to the matrix similarity theory, which lays a foundation for the research on oscillation characteristics, mechanism analysis, and suppression measures. Combined with the different installation positions of the inverter-side converter and the inverter-side POD (Power Oscillation Damper) controller of the energy storage device, the suppression mechanism and damping oscillation ability of the two on low-frequency oscillation were analyzed. Under multiple optimization objectives, the parameters of the damping controller are optimized by Pareto and improved particle swarm algorithms. Finally, through Matlab/Simulink simulation, the effectiveness of the Pareto and improved particle swarm algorithm in suppressing low-frequency oscillation of the system is verified. doubly-fed wind turbines; energy storage devices; low-frequency oscillation; power oscillation damper; control strategy; parameter optimization +
Footnote †: journal: _Sciences_  
regional power grid with high permeability of wind power and affect the power system's power grid scheduling and peak shaving frequency regulation. The large-scale development of wind power is imperative, but due to the randomness of wind energy, wind power generation has certain volatility [1]. On a long-term scale, wind power output fluctuates irregularly with changes in wind speed, while on a short-term scale, wind power output suddenly changes or even disappears. The intermittency and volatility of wind power make the output power of wind power extremely unstable. Maintaining a balance between power generation and load supply and demand is a key concern for maintaining the stability and reliability of the power system. The power system with a high proportion of wind power lacks the inertia and damping [2] provided by synchronous generators (SGs) in traditional power systems, which changes the oscillation characteristics of the system and cannot guarantee the stable operation of the power system. Low-frequency oscillation (LFO) in the power grid generally refers to the weakly damped oscillation process between 0.1-2.5 Hz. The lower the oscillation frequency, the more serious the consequences on the stability of the power system. Adding POD to wind turbines increases damping by controlling their output. The control effect of POD may exacerbate the oscillation of DFIG (Doubly Fed Induction Generator) [3] itself, threatening its stability. Therefore, this article takes into account the negative impact of POD on DFIG, introduces relevant safety constraints, reasonably plans and allocates frequency modulation tasks, and maintains the operational safety of DFIG while suppressing oscillation [4]. Adding a POD to the ESS is to increase the damping by controlling the output power of the energy storage.ESS (Energy Storage System) has the advantages of fast response speed and bidirectional power regulation, which can effectively improve the output characteristics of wind farms and suppress wind power fluctuations. Large-scale energy storage optimizes the operational performance of wind power connected to the power grid by suppressing wind power fluctuations or shifting the time and space of the grid load, thereby improving the stability of system operation, reducing the peak valley difference of power system load, and improving power quality and supply reliability. Installing ESS for wind farms is an effective way to improve the characteristics of wind power generation and improve the coordination performance between sources and networks. Among many energy storage methods, battery energy storage uses Redox to store and release electric energy, which has the characteristics of fast response, high efficiency, long life, convenient installation and configuration, and low cost. It is the most widely used energy storage method at present.