以新能源为主体的微电网系统存在前期资本投入大、电网刚性不足等问题,特别是离网型微电网由于失去大电网的支撑,安全稳定运行面临更大的挑战.本文针对离网型交流微电网设计了双层调度策略,即经济最优化日前调度和日内稳定运行实时调度,在多时间尺度下灵活规划发电主体出力.首先,日前调度以微电网经济性运行为目标,利用全生命周期理论建立经济模型,计及储能电池荷电状态(state of charge,SOC)对寿命的影响;其次,日内实时调度以供电稳定性为目标,充分考虑预测误差给系统带来的可能性崩溃,利用储能PQ源实时修正VF源的功率偏差,改善储能VF源的健康状态;最后,通过算例仿真,得到满足微电网经济、稳定运行的综合优化调度方案,并验证了该策略的有效性和合理性.
Bi-level Optimal Dispatching Strategy for off-grid Wind-Solar-Storage AC Microgrid Based on Whole Life Cycle Management
The microgrid system with new energy as the main body has problems such as large initial capital investment and insufficient rigidity of the grid,in particular,the off-grid microgrid faces greater challenges in safe and stable operation due to the loss of support from the large grid.This paper designs a Bi-level dispatch strategy for an off-grid AC microgrid,namely,economic optimization for day-ahead scheduling and real-time dispatch for stable operation within the day,planning the output of power generation entities flexibly under multiple time scales.Firstly,the objective is economical operation of the microgrid in the day-ahead stage,,utilizing whole life cycle theory to establish an economic model,and taking into account the impact of the battery's State of Charge(SOC)on its lifespan.Secondly,the goal is supplying stability for the day-of operation,,fully considering the potential system collapse due to forecast errors and using the energy storage's PQ source to real-time correct power deviations of VF sources,improving the health status of storage VF sources.Finally,through simulation examples,a comprehensive optimization dispatch scheme for the economic and stable operation of the microgrid is obtained,verifying the effectiveness and rationality of the strategy.
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