摘要
超高压线路故障时产生的周期性暂态高频分量,在频域上表现为一系列固有频率的形式,该频率随故障点位置、系统运行方式和过渡电阻变化而变化。针对传统快速傅里叶(FFT)算法,在采样频率较高的情况下,频率分辨率不足,无法准确识别固有频率的问题,提出了一种基于复解析带通滤波器的固有频率自适应提取方法,首先对故障后的电流进行FFT分析,确定固有频率的大致范围,然后设计复解析带通滤波器对原信号重新下采样、滤波,经移频得到新信号,对其进行FFT谱分析,得到固有频率的准确值。利用PSCAD对一500kV输电系统进行了仿真验证,仿真结果表明,该方法能够有效提高频率分辨率,可以准确提取固有频率值。
The fault-generated high-frequency signals in EHV transmission line is a series of natural frequencies in frequency domain. They vary with fault location, operation mode of system and fault resistance. For the lack of frequency resolution for FFT algorithm when high sampling frequency, natural frequencies can＇t be sampled accurately. A new method based on multiple analytical band-pass filter is presented to extract natural frequencies adaptively. Firstly, the approximate range of natural frequency is determined from spectrum, then the signals are resampled and filtered through a multiple analytical band-pass filter, and the natural frequency is extracted accurately after shift frequency by analyzing spectrum of resampling signal using FFT. A typical 500kV system in PSCAD is used to verify the performance. The simulation results show that the method presented can improve frequency resolution and natural frequency can be extracted accurately.
出处
《电工技术学报》
EI
CSCD
北大核心
2009年第12期179-184,共6页
Transactions of China Electrotechnical Society
关键词
继电保护
固有频率
复解析带通滤波器
多相结构
重采样
频谱分析
Relay protection
natural frequency
multiple analytical band-pass filter
heterogeneous structure
resample
spectrum analysis
