Additive white noise in power systems
I have been trying to find the level of white noise that can be expected when recording current waveforms on a distribution feeder. Suppose I have a 33 kV feeder carrying 400 A peak, what is a realistic range of SNR? Is it around 40dB or more? Or does the white noise affect the signal amplitude in the order of milliamps or amps (say 3% of peak)? Any help from some power system protection engineer will be much appreciated.