摘要
研究了智能变电站普遍采用的线性插值法,并针对幅值衰减问题提出了改进方法。首先采用离散传递函数的方法,推导了线性插值的幅值增益公式。进而分析了线性插值的幅频特性,并评估了幅值衰减对保护、测控等环节的影响。在现有的4 k Hz采样率下,线性插值不能完全满足采样环节对谐波幅值精度的要求。在此基础上,利用幅值增益相对于插值位置的对称性,提出了一种改进的插值方法。经理论证明,该方法对各频率信号的幅值增益恒为1。然后,给出了该方法的软件实现过程,特别是初值的选择,并分析了算法的稳定性。最后,结合具体的波形,通过FFT分析验证了该方法的插值效果。分析结果表明,所提的改进方法可以解决线性插值的幅值衰减问题。
The linear interpolation method commonly used in intelligent substations is researched, and an improved method is proposed for the problem of amplitude attenuation. First of all, the amplitude gain formula of linear interpolation is derived by using the discrete transfer function. Then the amplitude frequency characteristic of linear interpolation is analyzed, and the influence of amplitude attenuation on the protection and measurement is evaluated. In the 4 k Hz sampling rate, the linear interpolation can not meet the requirement of harmonic accuracy. On this basis, an improved interpolation method is proposed, using the symmetry of the amplitude gain about the interpolation position. The theoretical proof shows that the amplitude gain of each frequency signal is 1. Additionally, the software implementation process is given, particularly the selection of the initial value, and the stability of the method is analyzed. Finally, the interpolation effect of the method is verified by FFT analysis. The results show that the improved method can solve the problem of amplitude attenuation of linear interpolation.
出处
《电力系统保护与控制》
EI
CSCD
北大核心
2017年第3期105-110,共6页
Power System Protection and Control
关键词
智能变电站
线性插值
幅值增益
谐波精度
FFT分析
intelligent substation
linear interpolation
amplitude gain
harmonic accuracy
FFT analysis
