Power quality analysis involves the measurement of
quantities that characterize the power supply waveforms such as
RMS value, frequency, harmonic and inter-harmonic distortion or
the presence of transients. The measurement of these quantities is
regulated by internationally accepted standards from IEEE or
IEC. In particular, for the evaluation of frequency and RMS
values, the standard suggests the detection of the waveform zero
crossings. Thus, accurate zero crossing detection is of utmost
importance in power quality measurements. The undesirable
effects of noise, harmonics and transients can be mitigated by
filtering of the acquired waveforms, which induces a frequency
dependent delay in the processed waveforms. This paper presents
a comparative analysis between two types of filters. A comparative
analysis is performed between the use of a fixed nominal delay and
a frequency corrected delay. Additionally, the effect of the
presence of noise and harmonics in the delay compensation is
presented.