考虑风-储-直参与调频的电力系统频率特征定量分析

以风电、储能、柔性直流输电为代表的高比例可再生能源和大量电力电子设备的并网，使得电网中传统火电的比例下降，这将在一定程度上影响电力系统的频率稳定性。为定量分析风电、储能、柔性直流输电系统参与调频下电力系统的频率特征，首先提出多种调频资源参与调频下的电网频率特征定量分析总体思路，建立风-储-直调频频率响应模型。然后基于频率特性传递函数对电力系统稳态频率偏差、初始频率变化率、最大频率偏差和频率安全裕度进行理论推导；且定量分析了稳态频率偏差变化规律以及惯性时间常数、辅助调频单元控制比例系数对频率稳定性的影响，并计算稳态频率偏差与功率扰动的关系。最后，基于仿真软件验证了所提分析方法的可行性和有效性。仿真表明所提方法可有效定量分析电力系统频率特征，可为双高电力系统下电网频率安全稳定运行与控制提供指导依据。

Quantitative analysis of power system frequency characteristics considering wind power-energy storage-flexible HVDC transmission participation in frequency modulation

The integration of a high proportion of renewable energy and a large number of pieces of power electronic equipment represented by wind power, energy storage, and VSC-HVDC transmission has reduced the proportion of traditional thermal power in the grid. This will affect the frequency stability of the power system. In order to quantitatively analyze the frequency characteristics of the power system under the joint frequency modulation of wind power, energy storage, and VSC-HVDC systems, this paper first proposes the overall idea of quantitative analysis of the grid frequency characteristics in these circumstances and establishes a wind power-energy storage-flexible HVDC transmission joint frequency modulation frequency response model. Second, based on a frequency characteristic transfer function, this paper theoretically deduces the steady-state frequency error, the initial frequency change rate, the maximum frequency deviation and the frequency safety margin of the power system. Then it quantitatively analyzes the variation law of steady-state frequency error and the influence of the inertia time constant and auxiliary frequency modulation unit control proportional coefficient on frequency stability, and calculates the relationship between steady-state frequency error and power disturbance. Finally, the feasibility and effectiveness of the analysis method proposed are verified by simulation software. The simulation shows that the method proposed can effectively and quantitatively analyze the frequency characteristics of the power system, and can provide guidance for the safe and stable operation and control of the frequency of the power grid for a power system with a large amount of renewables and number of power electronics.