Optimization models for expansion planning of power systems aim to determine capacities, investment timing, and location of power systems to satisfy the power demands while minimizing the total cost. The models have become complex in recent years to reflect both regulations on conventional energy sources and the increasing penetration of renewable energy sources (RES). This paper reviews the basic concepts and optimization models for expansion planning of power systems. We first explain the definition and features of generation expansion planning (GEP), transmission expansion planning (TEP), and generation and transmission expansion planning (GTEP). To address the computational challenges of large-scale expansion planning problems, we review several simplifications including temporal and spatial aggregation, and decomposition methods. This paper also addresses power system reliability defined as the probability of satisfying the load demand while withstanding failures of components. The goal of this paper is to provide a research overview, discuss trends in expansion planning of power systems, and suggest directions for future research.

电力系统扩展规划的优化模型旨在确定电力系统的容量、投资时机和位置，以满足电力需求，同时最大限度地降低总成本。近年来，这些模型变得越来越复杂，既反映了对传统能源的监管，也反映了可再生能源 (RES) 的日益普及。本文回顾了电力系统扩容规划的基本概念和优化模型。我们首先解释发电扩展计划（GEP）、输电扩展计划（TEP）和发电和输电扩展计划（GTEP）的定义和特点。为了解决大规模扩展规划问题的计算挑战，我们回顾了几种简化方法，包括时间和空间聚合以及分解方法。本文还讨论了电力系统可靠性，定义为满足负载需求同时承受组件故障的概率。本文的目的是提供一个研究概述，讨论电力系统扩展规划的趋势，并为未来的研究提出方向。