A Convex Micro-Grid-Based Optimization Model for Planning of Resilient and Sustainable Distribution Systems Considering Feeders Routing and Siting/Sizing of Substations and DG Units

Highlights • New convex optimization model is proposed for distribution system expansion planning. • Optimal resilient microgrid based planning. • Routing and hardening of feeders, sizing and siting of substations and distributed generators. • Emission reduction as well as uncertainty of wind generations is also taken into account. • Reconfigurable microgrids to tackle with severe outage states. Abstract Integration of distributed generation (DG) and renewable energy resources (DERs) has affected planning and operation of recent distribution networks (DNs). On the other side, resiliency and sustainability of DNs is the other concern of distribution network operators. In this paper, a new formulation is developed for optimal planning of resilient DNs based on optimal formation of resilient micro-grids (MGs). The formulation aims to implement optimal siting and sizing of conventional and renewable-based DGs, optimal routing and type of feeders, as well as optimal sizing and placement of HV/MV substations to configure adequate and resilient MGs against extreme events. The investment, operational, emissions, and resiliency costs have been included in the objective function, and all the problem constraints as well as uncertainty of renewable DGs have been taken into account. The new formulation uses line-flow-based (LFB) model of AC power flow equations, and reserve feeders (tie-lines) are employed to enhance resiliency after severe outages via reconfiguration concept. All the relations have been convexfied in order to compose a mixed-integer quadratically-constrained (MIQCP) model to be solved with global optimum solvers in GAMS. Efficiency of the conducted methodology has been evaluated by different experiments on the 24-node system, and the results are investigated.### 研究亮点 • 针对配电系统扩容规划，提出了全新的凸优化模型。 • 提出基于弹性微电网的优化规划方案。 • 覆盖馈线路由优化与加固、变电站及分布式发电机的选址定容。 • 同时将减排目标与风电出力不确定性纳入考量。 • 通过可重构微电网应对极端停电场景。 ### 摘要 分布式发电（distributed generation, DG）与可再生能源资源（renewable energy resources, DERs）的并网，对当前配电网络（distribution networks, DNs）的规划与运行模式带来了显著变革。与此同时，配电网络的弹性与可持续性也成为配电运营商的核心关切之一。为此，本文围绕弹性配电网络的优化规划问题，基于弹性微电网（micro-grids, MGs）的优化构建思路，提出了全新的数学建模框架。该建模框架旨在优化常规及可再生式分布式发电机的选址定容、馈线路由与选型，以及高压/中压（HV/MV）变电站的选址与容量配置，从而构建能够抵御极端事件的可靠且具备弹性的微电网。目标函数整合了投资成本、运行成本、减排成本与弹性成本，同时全面覆盖问题的各类约束条件以及可再生分布式发电机的出力不确定性。本建模框架采用基于线路潮流（line-flow-based, LFB）的交流潮流方程模型，并通过备用馈线（联络线，tie-lines）的重构机制，在极端停电事故发生后提升系统弹性。所有约束关系均完成凸化处理，最终构建混合整数二次约束（mixed-integer quadratically-constrained, MIQCP）模型，可借助GAMS中的全局最优求解器实现全局最优求解。本文通过24节点系统的多组仿真实验，验证了所提方法的有效性，并对仿真结果展开了详细分析。