基于二分插值的动态谐波参数估计方法

Dynamic Harmonic Parameter Estimation Method Based on Binary Interpolation

摘要:

随着交直流配电网规模的不断扩大，低压配电技术得到广泛重视和发展，但谐波含量更高以及谐波幅值与频率呈现时变性等电能质量问题也越发凸显，使得快速傅里叶变换加窗插值方法取较长的序列导致谐波测量响应慢，无法适用于继电保护等快速响应类应用。针对此问题，提出了基于二分插值的谐波参数估计方法。首先，采用泰勒级数建立动态信号模型；其次，利用FFT对1个周波的数据进行扫频获得粗估频率，采用二分法迭代插值的方法，经系数修正得到估计频率；然后，基于估计频率和动态信号模型，利用最小二乘拟合方法求解信号参数；最后，在不同工况下验证算法的性能。仿真结果表明，所提方法仅用1个周波数据实现了动态信号参数的精准测量，总矢量误差均低于0.1%，为快速响应类应用数据分析提供有效方法。

Abstract:

With the continuous expansion of AC/DC distribution network, low-voltage distribution technology has received widespread attention and development. However, harmonic components account for a higher percentage and harmonic amplitudes and frequencies exhibit time-varying characteristics, the problem of power quality has become increasingly prominent. So, the fast Fourier transform (FFT) windowed interpolation method with longer sequences is slow in responding to harmonic measurements, making it unsuitable for applications that require rapid response such as protective relaying. Aiming at this problem, a harmonic parameter estimation method based on binary interpolation is proposed. Firstly, a dynamic signal model is established using Taylor series. Secondly, FFT is used to sweep the frequency of a waveform to obtain a roughly estimated frequency. And then, a binary iteration interpolation method is employed, along with coefficient correction, to obtain the estimated frequency. Based on the estimated frequency and dynamic signal model, a least squares fitting method is used to solve the signal parameters. Finally, the algorithm′s performance is verified under different operating conditions. Simulation results show that the proposed method achieves precise measurement of dynamic signal parameters using only one cycle of data, with total vector error (TVE) consistently below 0.1%, which provides an effective approach for data analysis in fast response applications.