赵凤展, 张启承, 张宇, 杜松怀, 郝帅, 苏娟, 赵婷婷. 基于VMD-MPC法的并网型微电网多时间尺度能量协调优化调度[J]. 农业工程学报, 2021, 37(7): 190-198. DOI: 10.11975/j.issn.1002-6819.2021.07.023
    引用本文: 赵凤展, 张启承, 张宇, 杜松怀, 郝帅, 苏娟, 赵婷婷. 基于VMD-MPC法的并网型微电网多时间尺度能量协调优化调度[J]. 农业工程学报, 2021, 37(7): 190-198. DOI: 10.11975/j.issn.1002-6819.2021.07.023
    Zhao Fengzhan, Zhang Qicheng, Zhang Yu, Du Songhuai, Hao Shuai, Su Juan, Zhao Tingting. Multi-time scale coordinated optimal energy dispatch of grid-connected microgrid using VMD-MPC[J]. Transactions of the Chinese Society of Agricultural Engineering (Transactions of the CSAE), 2021, 37(7): 190-198. DOI: 10.11975/j.issn.1002-6819.2021.07.023
    Citation: Zhao Fengzhan, Zhang Qicheng, Zhang Yu, Du Songhuai, Hao Shuai, Su Juan, Zhao Tingting. Multi-time scale coordinated optimal energy dispatch of grid-connected microgrid using VMD-MPC[J]. Transactions of the Chinese Society of Agricultural Engineering (Transactions of the CSAE), 2021, 37(7): 190-198. DOI: 10.11975/j.issn.1002-6819.2021.07.023

    基于VMD-MPC法的并网型微电网多时间尺度能量协调优化调度

    Multi-time scale coordinated optimal energy dispatch of grid-connected microgrid using VMD-MPC

    • 摘要: 对于含有不同类型储能和分布式电源(Distributed Generation, DG)的并网型微电网,如何优化调度这些设备以提高设备的使用寿命同时平抑DG出力和负荷的波动性与不确定性对配电网的影响具有重要的研究意义。该研究提出一种基于变分模态分解(Variational Modal Decomposition, VMD)和模型预测控制(Model Predictive Control, MPC)相结合的、多时间尺度滚动优化兼具反馈矫正的微电网优化调控模型,该模型在调度过程中考虑了不同类型储能和可控微电源在不同时间尺度上的运行特性,设计了1 h和15 min相结合的调度控制策略,有效解决了含多种微电源及储能设备的微电网的经济优化调度问题;最后,通过算例对比验证了此模型能比较显著地降低铅酸蓄电池充放电频率和系统的运行成本、改善了调度经济性,证明了该方法的有效性和优越性。

       

      Abstract: Distributed Photovoltaic (PV) is ever increasing in the power grid, as the current PV generation rapidly developed. However, it is difficult to directly coordinate the PV into the conventional power grid, due mainly to the intermittent and uncertain nature of PV power generation. As such, there is a great impact on the power flow of a system, particularly the volatility and uncertainty of the output and load demands of Distributed Generation (DG) power in grid-connected microgrids. A friendly way is widely expected that the PV can access the distribution network in the form of a microgrid for the enhanced DG absorption capacity. It is highly urgent to reduce the impact of such volatility and randomness on the energy transmission between microgrids and distribution networks. In this study, a multi-time scale coordinated optimization was performed on energy scheduling strategies using a Variational Modal Decommission-Model Predictive Control (VMD-MPC). Specifically, an MPC was a sort of optimal control with a closed-loop over a finite time domain, suitable for the nonlinear, time-varying, and uncertainty of the system. There was no differentiation scheduling on the forecast of PV power for each Controllable Micropower (CMS)in the microgrid operation because the load was directly applied in the previous multiple-time scale scheduling using MPC optimization. Consequently, some CMS (such as a Lead-Acid Battery, LAB) was run in a short time, high strength, and energy scheduling, whereas, some CMS (such as a Super Capacitor, SC) was only for a long and slow energy scheduling. Thus, the operating characteristics of CMS in different time scales should be considered in the optimization of scheduling. A VMD was utilized to acquire the different loads and subsequence in the PV series of frequency scales, thereby achieving the multiple coordinated optimization scheduling CMS models in different time scales. The scheduling model included a longtime scale of 1 hour and 15 min interval time for a short scale. Dispatching LAB, Micro gas Turbine (MT), and small Biomass Generator (BPG) were usually responded to the signals of a long-time scale. Scheduling SC, MT and BPG were responded to the signals of a short-time scale. The final scheduling was achieved for each CMS to realize the differentiated optimal processing of signals on different time scales, where the calculated values of each model were summed up. Then a feedback correction model was constructed to form a closed-loop control using the day-ahead scheduling, where the difference between the ultra-short-term forecast within the day and the day-ahead forecast was taken as the disturbance input, while the current operating state of the system was taken as the parameter, and the power increment of each CMS was taken as the control variable. The feedback correction effectively enhanced the robustness, while reduced the impact of the system that resulted from the uncertainty of load and PV output. As such, the optimal energy scheduling strategy effectively coordinated the grid-connected microgrids with multiple micro power sources and time scales. Taking a PV microgrid in North China as an example, an MATLAB software was used to simulate and verify the model, indicating optimal scheduling. Better feasibility, effectiveness, and economy of strategy were achieved from the perspectives of power scheduling and operating cost, compared with the traditional active power and MPC multi-time scale scheduling strategy. Accordingly, this finding can provide a practical and effective technical approach for high-permeability microgrids in energy trading under the environment of multiple renewable energy consumption and electricity market.

       

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