孤网失稳状态下频率和暂态谐波分析方法

针对孤网失稳状态下频率和谐波快速宽频变化导致的傅立叶谐波分析频谱泄漏问题,提出了一种基于自适应变带宽周期滑动滤波的频率和暂态谐波分析方法.首先通过基于周期滑动滤波原理的预处理系统消除非平稳信号的高频周期干扰,并剔除直流分量;然后对预处理后的序列采用零交法进行实时锁相,自适应调整周期滑动滤波器的带宽;最后根据计算的非平稳...

An Analysis Method for Frequency and Transient Harmonics of Isolated Network Under Instable Condition

Focusing on the problem of spectrum leakage in Fourier harmonic analysis caused by rapid broadband changes in frequency and harmonics in isolated network under unstable condition, an analysis method for frequency and transient harmonics is proposed based on adaptive periodic sliding filter with variable bandwidth. Firstly, the high-frequency periodic interference of non-stationary signal is eliminated by the preprocessing system based on the principle of periodic sliding filter, and the DC component is separated. Then the preprocessed sequence is locked in real time by zero crossing method, and the bandwidth of the periodic sliding filter is adjusted adaptively. Finally, according to the real-time frequency of the calculated non-stationary signal, the non-stationary signal is divided into harmonics by the discrete Fourier transform (DFT) algorithm, and the transient information of each harmonic component is obtained accurately. Simulation results and field measurement data show that the method has high harmonic measurement accuracy under a variety of non-stationary states, and can effectively measure the frequency and transient harmonics of isolated network under the unstable state.