考虑三相不平衡潮流的微网分相优化调度

摘要

由于微网中微源和负荷存在不对称性,若微源出力仍采用传统的三相对称模型,则并网时外网与微网间的联络线功率的对称性较差,孤网时由于没有微源能够承受微网的不平衡性导致微网无法稳定运行.提出考虑三相潮流与制热收益的热电联产型微网系统分相优化调度模型.以热电联产型Benchmark微网为例,提出并网和孤网运行方式下的调度策略.在考虑实时电价和保证敏感负荷供电可靠性的基础上,运用改进遗传算法优化各微源的每相有功、无功出力及微网向外网的购售电量.对比分析2种运行方式下一天内蓄电池的充放电次数、切负荷量、综合成本以及电压质量.算例验证了所提模型、策略和算法的有效性.%Because of the unbalance of microsources and loads,if using the traditional three-phase symmetric model for the power output of microsource,the symmetry of tie-line power between external network and microgrid will be worse in grid-connected mode and microgrid can't operate stably in islanded mode for no microsource can undertake the unbalance of microgrid.An optimal single-phase scheduling model for CHP(Combined Heat and Power)-based microgrid is proposed,which considers three-phase power flow and heating benefit.Taking CHP-based Benchmark microgrid as an example,the scheduling strategies under the grid-connected mode and the islanded mode are proposed.On the basis of real-time electricity price and reliable power supply of sensitive loads,the improved genetic algorithm is adopted to optimize the active and reactive power in each phase of each microsource and the purchasing and selling electric quantity of microgrid from the external grids.The charging and discharging times of storage battery,shedding load,comprehensive cost,and voltage quality in one day are compared between the two operation modes.Case verifies the effectiveness of the proposed model,strategy and algorithm.