Research On Optimal Allocation Of Landscape Storage In Large Parks Considering Grid-connected Fluctuation

To facilitate the energy structural transformation of the park,the concept of multienergy complementary development will be further implemented,and a microgrid system integrating renewable energy generation and energy storage control will be built in the existing park.Considering the intermittency of solar power,the grid-connected fluctuations of renewable energy can be reduced by energy storage adjustment.With the advantages of fast power response and high energy density,hybrid energy storage technologies with batteries and supercapacitors can efficiently transfer fluctuations in grid connections and improve energy utilization in solar renewable generation systems.Therefore,in this paper,we focus on the park’s wind storage complementary power generation system,in which we thoroughly investigate the wind storage capacity allocation method by considering the wave suppression and short-time optimization operation strategies of the grid-connected microgrid,and demonstrate the effectiveness of the proposed scheme set out in this paper through simulation analysis.Major studies include:(1)Firstly,the power generation characteristics of the renewable energy system in the park are analyzed,and the rationality of the wind-landscape capacity allocation is judged by the complementarity index.Current park energy storage technologies are summarized and analyzed to determine the combination of battery energy storage technology and supercapacitor energy storage technology to build a hybrid energy storage system.Ac-dc hybrid mode is adopted to construct the micro-grid structure of the park,wherein the renewable power generation system and hybrid energy storage system are connected to the DC bus through the DC/DC bidirectional converter,and the DC bus is connected to the AC power grid through the two-way DC/AC grid-connected inverter.(2)Specific wind power,photovoltaic and hybrid energy storage capacity allocation methods of mi cro-grid in the park were constructed considering the grid-connection fluctuations.Inspired by the two-layer optimization idea,a model is developed in which the capacity allocation and optimal scheduling of microgrids are divided into upper and lower optimization layers,respectively.The upper optimization model is the optimal economic allocation of microgrid capacity,and the lower optimization model is the short-term optimal economic operation of the microgrid taking into account the lifetime loss of energy storage.As for the solution procedure for bilayer optimization,the general solution efficiency of the single-objective algorithm is not very high.In this paper,we use the multi-objective genetic algorithm as the solution algorithm for the two-layer optimization model.In order to solve the hard problem of self-running constraints in energy storage systems,a spatially transformed constraint treatment is proposed and a multi-objective genetic algorithm is improved to solve the problem.(3)Carry out a detailed study on the fluctuation suppression of the park configuration scheme,use the sliding average method and the improved multiscale morphological decomposition method to distribute the power of the hybrid energy storage system,and transfer the fluctuation energy of the park micro-grid during grid-connected through the regulation of hybrid energy storage.First,grid-connected power from solar renewables and pre-processed power from hybrid storage systems are obtained using a sliding average method.The modified multiscale structure element judgment method ADAPTS scales the multiscale decomposition based on the characteristics of the preprocessed power signal.Second,a multi-scale decomposition of the pre-processed power signal is performed with a morphological filtering operator to obtain the power component signal at each scale.Moreover,the power component signals are reconstructed by a t-test to assign specific high and low frequency energies to the ultracapacitors and batteries.(4)This paper takes the existing large parks in Central Jiangsu as an example to simulate the two-layer optimization model established.The results show that promoting the construction of scenic energy sources in parks can effectively complement energy utilization methods,replace some of the main electricity with clean and renewable sources,and save fossil energy consumption.Meanwhile,in this paper,we consider the suppression of fluctuations of a microgrid in a park when it is connected to a power grid.The established hybrid renergy storage reasonably distributes the fluctuating energy flow under the principle of high and low frequency decomposition,which reduces the maximum fluctuation by 1 min to 1.45%and by 10 min to 5.69%when the park is connected to the grid,effectively improving the quality of clean electricity.At the same time,the influence of energy storage collocation mode and energy storage operation mode on the micro-grid operation in the park is also analyzed,indicating that the combination of supercapacitor and battery energy storage can well reflect the complementary advantages of power type energy storage and energy type energy storage.By adding a supercapacitor of a certain capacity,the safe operation of the battery can be significantly protected,the lifetime of the battery can be extended,and substantial energy storage investment costs can be saved.In addition,the feasibility of multiple working modes of batteries in park microgrids has also been investigated.The results show that,through simple frequency division regulation,the battery used for grid-connected fluctuation absorption can basically maintain the same working scale as the short-time regulation battery,so that the purpose of single energy storage and multi-mode operation can be realized by relatively simple,which is also the full utilization of energy storage resources.