摘要
在电力设备介质损耗在线监测中,由于对连续工频周期信号的截断和非同步采样,会给基于传统FFT的谐波分析法带来显著的误差。笔者在前人的基础之上,对高精度FFT算法进行了详细的推导,并给出了加Blackman-Harris窗插值算法的实用公式。针对实际电网频率波动引起的非同步采样,通过MATLAB软件对普通FFT算法、加Blackman窗和加Blackman-Harris窗的插值算法进行仿真。仿真结果分析表明采用加Blackman-Harris窗插值的高精度FFT算法可以有效地降低测量误差和提高监测精度,满足现场电力设备介损监测的要求。
In on-line monitoring tanδ of power equipment, the harmonic analysis based on conventional FFT brings significant errors because of the truncation of power frequency signal and unsynchronized sampling sequence. In this paper, the window and interpolation algorithm is derived, and a practical interpolation formula with Blackman-Harris window is proposed. For the unsynchronized sampling sequence caused by frequency fluctuation of power system, the simulation is performed via MATLAB code on the conventional FFT algorithm the interpolation algorithm with Blackman window, and the interpolation algorithm with Blackman-Harris window, respectively. The simulation results show that the interpolation algorithm with Blackman-Harris window can effectively reduce the measurement error and increase the precision, which satisfies the requirement for on-line monitoring tanδ of power equipment.
出处
《高压电器》
CAS
CSCD
北大核心
2009年第2期57-61,共5页
High Voltage Apparatus
关键词
介损在线监测
非同步采样
谐波分析
快速傅里变换
频率波动
加窗插值算法
on-line tanδ monitoring
unsynchronized sampling sequence
harmonic analysis
FFT
frequency fluctuation
window and interpolation algorithm
