飞轮储能辅助火电机组一次调频控制策略

Primary Frequency Regulation Control Strategies for Thermal Power Units Assisted by Flywheel Energy Storage

摘要:

为应对新能源大规模并网造成的电力系统频率不稳定性问题，提出了一种基于飞轮储能辅助火电机组一次调频控制策略。针对火电机组爬坡速度慢、易引发机组振荡等问题的影响，利用飞轮储能的高频次瞬间精准放电、高转换效率及长寿命等特点来弥补传统调频方式的不足。基于 Matlab/Simulink 建立了含火电与飞轮储能的电力系统频率特性模型，对比分析了火电机组单独调频、定系数下垂控制以及变系数下垂控制下飞轮储能辅助调频的电力系统频率特性、机组输出功率以及联络线交换功率变化。仿真结果表明：飞轮储能的引入能够显著提高电力系统频率稳定性，减少火电机组出力并延长其寿命；变系数下垂控制充分考虑了储能荷电状态，相较于定系数下垂控制，变系数下垂控制下储能荷电状态变化范围缩小，能够减少储能过充过放等问题。

Abstract:

To address the frequency instability in power systems caused by the large-scale integration of new energy sources, a primary frequency regulation control strategy for thermal power units assisted by flywheel energy storage (FES) is proposed. This strategy aims to make up for shortcomings of traditional frequency regulation methods, such as slow ramping speed and potential oscillations of thermal power units, with the characteristics of FES, including its high-frequency instantaneous precise discharge capability, high conversion efficiency, and long service life. A power system frequency characteristic model incorporating thermal power and FES is established using Matlab/Simulink. Comparative analyses are carried out on power system frequency characteristics, unit output power and tie-line power exchange under three different control scenarios: thermal power unit frequency regulation alone, fixed-coefficient droop control and variable-coefficient droop control with FES-assisted frequency regulation. The simulation results show that the introduction of FES significantly enhances the frequency stability of power system, reduces the output power of thermal power units, and prolongs its service life. Moreover, compared with the fixed-coefficient droop control, variable-coefficient droop control takes into account the state of charge (SOC) of energy storage system, which can narrow the variation range of SOC and effectively mitigate overcharging and over-discharging of energy storage system.