计及频率响应时空相关性的新能源电力系统惯量估计方法

Inertia Estimation Method for Power System with Renewable Energy Considering Spatio-temporal Correlation of Frequency Response

高比例新能源电力系统惯性水平低、不确定性强,系统惯性水平与频率动态响应过程密切相关。系统内各节点之间的频率响应过程在时空上具有相关性,动态量化节点间频率的时空相关性是实时估计新型电力系统惯量的技术手段。首先,给出了面向同步机组和新能源发电机组惯量的计算方法;其次,利用Granger因果检验算法,动态分析系统内不同节点之间频率的相关性,构建随时间变化的系统频率时空因果相关集合;此外,基于系统内各节点频率响应过程的摇摆方程,建立系统惯性常数-频率状态空间模型;然后,基于无迹卡尔曼滤波器和固定滞后平滑器,提出高比例新能源电力系统惯量估计方法;最后,在改进的IEEE 39节点系统中验证了所提方法的有效性和适用性。结果表明,所提方法可以在不同新能源渗透率和频率扰动场景下保证惯量估计效果的一致性,具有工程应用潜力。

The power system with high-proportion renewable energy has low inertia level and high uncertainty.The system inertia level is closely related to the dynamic frequency response process.Considering the spatio-temporal correlation of frequency response process between nodes within the system,dynamically quantifying the spatio-temporal correlation of frequency between nodes provides an effective technique for real-time inertia estimation in the new power system.Firstly,a calculation method for inertia of synchronous units and renewable energy generator units is proposed.Secondly,the Granger causality test algorithm is used to dynamically analyze the frequency correlation of different nodes in the system,thereby establishing a time-varying spatiotemporal causal correlation set of system frequency.Furthermore,based on the swing equation of frequency response processes of various nodes in the system,a system inertia-frequency state space model is constructed.Subsequently,a novel method for estimating the inertia of power system with high-proportion renewable energy is proposed using the unscented Kalman filter and fixed-lag smoother.Finally,the proposed method is validated using an improved IEEE 39-node system,demonstrating its effectiveness and applicability.Results show that the proposed method ensures consistent inertia estimation performance in different renewable energy penetration rates and frequency disturbance scenarios,which has engineering application potential.