黄瑞　肖宇　刘谋海　单铉昇　温和

摘   要：低频振荡是三相电力系统中的一种平衡现象，如何准确、快速地估计振荡信号的参数对于评估和消除低频振荡至关重要. 本文提出了一种采用复频谱插值DFT的低频振荡下电力系统动态信号参数估计的方法，该方法利用三相系统的对称特性，通过克拉克变换将电力系统中的三相实信号转换为正交分量形式的复信号，然后对复信号进行离散傅里叶变换，通过复频谱插值方法，利用两个幅度最大的谱线样本来估计各项动态参数. 实验仿真结果表明本文方法能在低频振荡的场景下准确高效地实现电网动态参数的估计.

关键词：复频谱插值;振荡信号;低频振荡;傅里叶变换;三相系统

中图分类号：TM935                             文献标志码：A

Estimation Method of Power System Oscillation Signal under

Power Swing with Using Complex Spectral Interpolation DFT

HUANG Rui XIAO Yu LIU Mouhai SHAN Xuansheng WEN He

（1. College of Electrical and Information Engineering， Hunan University， Changsha 410082， China;

2. State Grid Hunan Electric Power Corporation Limited， Changsha 410004， China;

3. Hunan Province Key Laboratory of Intelligent Electrical Measurement and Application Technology，

Hunan University， Changsha 410082， China）

Abstract：Power swing is a balanced phenomenon in a three-phase power system， where accurate and fast parameter estimation of oscillation signal is important for the evaluation and elimination of power swing. This paper presents a method for parameter estimation of power system oscillation signal under power swing based on complex spectral interpolation DFT. The proposed method utilizes the symmetrical characteristics of a three-phase system. A complex exponential with the quadrature components is formed from three-phase real signals by using the Clarke transform. The DFT of the complex exponential is then performed. Moreover， various dynamic parameters are estimated by complex spectral interpolation using two DFT samples with the largest magnitude. The experimental simulation results show that the proposed method can accurately and effectively assess the dynamic parameters of power system under the power swing.

Key words：complex spectral interpolation;oscillation signal;power swing;Fourier transform;three phase system

電网参数的准确估计是电能计量、电能质量检测、继电保护的重要基础. 电力系统的干扰，例如故障，大负载的开/关，发电机的断开，线路切换等，会导致发电机之间的转子角发生振荡从而导致电网产生低频振荡. 如何在低频振荡情况下实现电网参数准确快速测量，对维持电力系统稳定运行起着至关重要的作用[1].

近年来，很多学者与研究机构对于电网动态参数测量进行了研究. 其中常用的测量方法主要有：基于正弦信号模型的检测算法;周期法及其改进算法，主要包括过零检测法、水平交点法、高次修正函数法和最小二乘多项式曲线拟合法等;随机模型算法，主要包括最小二……