Control Strategy Of Wind-Storage Combined System And Research On Economic Evaluation

As a mature renewable energy generation technology,wind power has attracted much attention.However,the inherent randomness and intermittence of wind power affect the safe and stable operation of the power system.Improving the schedulability of wind power is the key to large-scale grid connection of wind power.Besides,wind power prices gradually changed from relying on government subsidies to parity.It is an inevitable trend for wind power and traditional energy to compete in the market,and the allocation of the energy storage system is an important means to improve the schedulability of wind power.How to improve the output level of wind power tracking plan and ensure the comprehensive economy of wind storage power station is of great significance to increase the market competitiveness of wind power generation.Therefore,the following research work is carried out in this paper:(1)Since the wind power signal cannot be described intuitively in the time domain,this paper uses Discrete Fourier Transform(DFT)to perform the time-frequency conversion on the wind power deviation and transform it into a frequency domain signal that can be clearly judged.Besides,the frequency domain signal is further divided into multiple layers,corresponding to the energy storage devices with different response times,and the control demand value of the energy storage device in the corresponding frequency band is obtained through spectrum analysis.(2)In order to adapt to the characteristics of wind power and improve the performance of wind power control to the level of thermal power units,this paper proposes an assessment standard that takes into account the dual requirements of short-term control and long-term control,so as to achieve the purpose of not only preventing the control from running off but also ensuring the real-time feedback of control effect.(3)In order to avoid frequent action of energy storage equipment,according to the response time,the power deviation of wind power is divided into high,medium,and low frequency by DFT,and the latter two are selected as the control input.At the same time,different thresholds will be set in the control area,and the energy storage equipment will issue corresponding instructions according to the current control area to prevent repeated adjustment.(4)In order to avoid excessive charging and discharging of energy storage equipment,according to different response characteristics,energy storage is divided into power type energy storage and energy type energy storage,and a hybrid energy storage system is formed.The charging and discharging rules between energy storage equipment are formulated to optimize the state of charge of energy storage equipment in real-time.(5)Given the economic problems of the energy storage system in the operation cycle,the comprehensive economic benefit evaluation model of the hybrid energy storage system in the whole life cycle is established,and the calculation method of the energy storage life for different types of energy storage equipment is put forward.According to the Markov chain Monte Carlo method(MCMC)combined with backward scene reduction technology to generate multiple simulation scenarios.Finally,the benefits of the energy storage system are evaluated by solving the model.Based on the above research,this paper has formed a direct control strategy for real-time tracking of wind power generation plans for wind storage power stations,which will contribute to the participation of wind power in the power market competition in the new development stage.