Strengthening power system dynamic operation with the advent of increased renewable generation: Location and control of fast energy storage systems

该研究项目旨在通过使用快速储能系统来提高电力系统的稳健性，从而使电网更好地准备承受可能导致停电的故障和异常运行。本项目的理论工作也将有助于为未来电力系统基础设施的动力学研究奠定基础。一些电力系统问题可以使用提出的数学发展来研究，如可再生能源发电的控制器设计、智能电网动态运行、电力市场等。除了推进电力系统动力学的研究知识外，该项目还将进一步发展控制理论，使其适用于电气工程、机械工程、化学工程和管理等领域的许多其他系统和工业过程。pi计划将研究成果用于电力系统动力学和控制新课程的课程开发。研究人员还将得到田纳西大学诺克斯维尔分校工程学院多样性办公室和信息技术办公室的支持。本项目将研究确定快速储能系统（FESS）最佳位置的标准，以改善电力系统的动态性能，并为FESS设计适当的控制。未来电网的特点可能是可再生能源通过电力电子设备与电网接口的高度渗透，这可能会导致由于惯性减少和发电侧的高可变性而导致动态性能差。为了测量动态性能的改进，考虑了频率最低点、频率变化率和低频振荡阻尼等特征。这项工作将是第一个在考虑电力系统动力学的完整数学复杂性（大维度，不同时间尺度的动力学，线性和非线性元素等）的同时提出FESS定位问题解决方案的工作之一。尽管该问题的建模非常复杂，但其中一个假设是存在基于电力系统特定物理特性（如惯性分布、同步发电机响应速度分布和电网拓扑）的FESS位置准则。数据分析将用于确定最佳位置和电力系统特性之间的相关性，并根据数值结果推导出该准则的理论发展。随着可再生能源发电量的增加，这一特征将允许规划者仔细加强电网动态。此外，本研究试图建立三种FESS控制策略：(a)连续控制方案；(b)离散控制方案，确定FESS需要改变其离散状态的具体时间（考虑三种状态：空闲、放电和充电）；(c)将离散状态转换和特定离散状态下的连续储能控制相结合的混合控制方案。混合控制方案有望提供最佳的动态改进，同时有望延长FESS的使用寿命。相量测量单元（pmu）的潜力被认为可以促进FESS，常规发电和可再生发电之间的协调控制回路。

This research project seeks to increase power system robustness through the use of fast energy storage systems so the grid is better prepared to withstand failures and abnormal operation, which may lead to blackouts. The theoretical work of this project will also contribute to establishing a basis for dynamics studies for the future power system infrastructure. Several power system problems can be studied using the proposed mathematical development, such as controller designs for renewable generation, smart grid dynamic operation, electricity markets, and others. Besides advancing research knowledge on power system dynamics, this project will bring further development in control theory that is applicable to many other systems and industrial processes from the fields of electrical engineering, mechanical engineering, chemical engineering, and management. The PIs plan to leverage research results for curriculum development in new courses on power system dynamics and control. The researchers will also have support from the Office of Diversity, College of Engineering, and the Office of Information Technology at the University of Tennessee, Knoxville.This project will investigate a criterion to identify the best locations of fast energy storage systems (FESS) to improve power system dynamic performance and design appropriate controls for FESS. The future power grid is likely to be characterized by a high penetration of renewable energy interfaced to the grid through power electronics, and this may result in poor dynamic performance due to the reduction of inertia and a high variability on the generation side. To measure dynamic performance improvement, features such as frequency nadir, rate of change of frequency, and low frequency oscillation damping, among others, are considered. This work would be among the first to propose a solution for the FESS location problem while considering the full mathematical complexities of power system dynamics (large dimensionality, dynamics in different time scales, linear and nonlinear elements, and others). Although the modeling of this problem is highly complex, one of the proposal hypotheses is the existence of a criterion for FESS location based on specific physical characteristics of a power system, such as distribution of inertia, distribution of response speed of synchronous generators, and grid topology. Data analytics will be used to identify correlations between the optimal location and power system characteristics and, based on the numerical results, the theoretical development of the criterion will be derived. This characterization would allow planners to carefully strengthen the grid dynamics with the advent of increased renewable generation. In addition, this research seeks to establish three control strategies for FESS: (a) a continuous control scheme; (b) a discrete control scheme that determines the specific time when FESS need to change their discrete states (three states are considered: idle, discharge, and charge); and (c) a hybrid control scheme that combines the discrete state transitions and the continuous stored energy control within a particular discrete state. The hybrid control scheme is expected to provide the best dynamic improvement and, at the same time, is expected to extend the lifespan of FESS. The potential of phasor measurement units (PMUs) is considered to facilitate coordinating control loops among FESS, conventional generation, and renewable generation.