计及微电网并离网两种工况的储能容量优化配置

对于并网型微电网的容量配置需同时考虑并离网状态。离网工作时,单靠储能满足微电网长时间内的能量平衡,往往配置容量较大且经济性欠佳。针对离网状态,提出了一种考虑充放电倍率特性的储能与柴油发电机协同配置方案,同时计及了电池的寿命模型。分别给出离网时考虑切负荷率的每个时段储能、柴油机联合出力模型,以及并网时考虑削峰填谷每个时段储能、联络线联合出力模型。以切负荷率和切负荷期望为指标参数,经济性和电网依赖度为优化目标,采用磷酸铁锂电池进行容量配置。最后,采用实际工厂数据进行仿真计算,验证了方法的合理性。

Optimal Capacity Allocation of Energy Storages in Microgrid Considering Grid-connected and Off-grid Operating Conditions

During the capacity allocation of a grid-connected microgrid, both grid-connected and off-grid statuses should be considered. In the off-grid mode, using energy storage alone can keep the energy balance in a microgrid for a long time; however, a larger capacity usually needs to be configured, and the corresponding economic efficiency is lower. By taking the battery life model into account, a collaborative allocation scheme of energy storages and diesel engine in an off-grid mode is proposed, which fully considers the characteristics of charging and discharging ratios. Afterwards, acollaborative output model of energy storages and diesel engine during each period in the off-grid mode(with the consi-der-ation of cutting load rate), and acollaborative output model of energy storages and tie-line during each period in the grid-connected mode(with the consideration of peak-load shaving), are given respectively. Lithium iron phosphate batte-ry is used to allocate the capacity with index parameters of cutting load rate and cutting load expectations, and with optimization objectives of economic efficiency and grid dependency degree. Finally, the data from an actual factory were used to perform simulations and calculations, which verified the rationality of the proposed method.