How to decide sampling frequency (is there any rule) for analysing the 3 phase voltage and current signals so as to use them as input to neural network for fault location

what should be the minimum sampling time so that short time transient peaks in power system (such as lightening surge )can be detected by the fault protection scheme(ANN based).

moreover, what is best way to feature extraction(scaling or normalization) of power signal data set so as to use them effectively to train ANN for fault detection.

[Star Strider]

What are the frequency characteristics of the ‘short time transient peaks’? If those are what you want to detect, their frequency spectra should determine your sampling rate. Your sampling frequency should be at least twice your highest frequency of interest.

Answer 1

[Greg Heath]

I can adequately represent one period of a sinusoidal wave with 8 equi-spaced points. So, choose the highest frequency you want to represent and start from there.

Thank you for formally accepting my answer

Greg

[STUDENT]

please elaborate more

[Greg Heath]

Plot one period of a sine wave. y = cos(t + 2*pi*rand);

Choose 8 equispaced points that cover the period

Plot the piecewise linear function represented by the 8 points

Overlay the plot on the sine-wave plot.

Not satisfied? Use more points.