Unequal reactive power sharing amongst distributed generators (DG) is a significant concern while operating a droop based microgrid. The reasons for this unequal reactive power sharing include the difference in feeder impedances, uneven distribution of loads and DGs in terms of size and locations. In this article, a mixed-integer linear programming (MILP) problem applicable for a droop based microgrid has been proposed to achieve proportional reactive power sharing amongst DGs while maintaining very low line losses. Firstly, the optimal sizing and placement of DGs are investigated. This includes a detailed discussion on the linearisation of various nonlinear terms involved in the formulation. Subsequently, a day–ahead dispatch is generated for these DGs for a given load profile. Additionally, network reconfiguration has been incorporated for further improvement in performance. The effect of considering a practical constant impedance-current-power (ZIP) load model, instead of simply considering constant impedance loads, has also been assessed. The proposed formulation has been tested on a 33 bus network which has been modified to represent an islanded microgrid. The results obtained validate the accuracy of the proposed planning and dispatch method and demonstrate its utility in achieving proportional reactive power sharing amongst the DGs while incurring very low line losses.

中文翻译：

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基于下垂的微电网的最佳DG分配和伏特-瓦尔调度

在运行基于下垂的微电网时，分布式发电机（DG）之间的无功功率分配不均是一个重大问题。这种无功功率分配不均的原因包括馈线阻抗的差异，负载和DG在尺寸和位置方面的分布不均。在本文中，提出了适用于基于下垂的微电网的混合整数线性规划（MILP）问题，以在DG之间实现成比例的无功功率分配，同时保持非常低的线损。首先，研究了DG的最佳尺寸和位置。这包括对公式中涉及的各种非线性项的线性化的详细讨论。随后，将针对给定的负载配置文件为这些DG提前生成调度。另外，网络重新配置已纳入，以进一步提高性能。还评估了考虑实际的恒定阻抗-电流-功率（ZIP）负载模型而不是简单地考虑恒定阻抗负载的效果。提议的配方已在33总线网络上进行了测试，该网络已进行了修改，以代表孤岛微电网。获得的结果验证了所提出的计划和调度方法的准确性，并证明了其在实现分布式发电装置之间成比例的无功功率分配的同时，其线路损耗非常低的实用性。提议的配方已在33总线网络上进行了测试，该网络已进行了修改，以代表孤岛微电网。获得的结果验证了所提出的计划和调度方法的准确性，并证明了其在实现分布式发电装置之间成比例的无功功率分配的同时，其线路损耗非常低的实用性。拟议的配方已在33总线网络上进行了测试，该网络已被修改以表示孤岛微电网。获得的结果验证了所提出的计划和调度方法的准确性，并证明了其在实现分布式发电装置之间成比例的无功功率分配的同时，其线路损耗非常低的实用性。