In this paper, a new under-frequency load shedding (UFLS) scheme is proposed for multi-microgrid (MMG) application. MMG, consists of multiple micro-grids, perhaps with different owners, connected together. Multiple owners make load shedding policies more complex in MMG compared to the policies employed in micro-grids and large power systems. Accordingly, an appropriate UFLS scheme is required, in order to ensure the frequency stability of the MMG, while considering its economic aspects. Therefore, in this paper, an optimization problem has been introduced which minimizes the cost imposed on the owners for mandatory load shedding alongside the cost of MMGs operation after the load shedding procedure. By solving the proposed optimization problem, the optimal locations of loads to be shed are determined. Two optimization algorithms – genetic algorithm (GA) and exchange market algorithm (EMA) – and GAMS software have been used for solving this optimization problem. A new index is introduced in this paper in order to distribute load shedding among MGs based on their total power generation and load demand. Simulation results confirm the efficiency of the proposed methodology.

在本文中，针对多微电网（MMG）应用提出了一种新的低频减载（UFLS）方案。MMG由多个微电网组成，这些微电网可能具有不同的所有者，并且彼此连接在一起。与微电网和大型电力系统中采用的策略相比，多个所有者使MMG中的减载策略更加复杂。因此，在考虑MMG的经济方面的同时，为了确保MMG的频率稳定性，需要适当的UFLS方案。因此，在本文中，引入了一个优化问题，该问题使在进行减载过程后MMG的运营成本以及强制减载对业主造成的成本降至最低。通过解决所提出的优化问题，可以确定要卸荷的最佳位置。两种优化算法-遗传算法（GA）和交易市场算法（EMA）-和GAMS软件已用于解决此优化问题。本文引入了一种新的指标，以便根据MG的总发电量和负载需求在MG之间分配减载。仿真结果证实了所提出方法的有效性。