Experimental Evaluation and Systematic-Error Reduction of Frequency Estimation Using the Zero-Crossing Technique for Dynamic Power Grids

Microscopic Fluctuations in Power-Grid Frequency Recordings at the Subsecond Scale

“…In dynamic conditions, however, the estimation errors are dominated by the principles of the zero-crossing method. A detailed analysis of the estimation errors in the time domain can be found in [21]. For the frequency ramps defned in the standard for Phasor Measurement Units (IEEE 60255-118-1) we found the error limit of our method to be ±0.6mHz.…”

“…Our measurement device, the electrical data recorder (EDR), was introduced some years ago and is being developed continuously; see also [18][19][20][21]. In the following, we provide a general overview of the data acquisition and frequency calculation.…”

“…To address this challenge, we introduced the partial period method (pp) in [21] that performs a local resampling of the data to the regular report intervals. Contributions of the border periods (i.e., periods 1 and 6 in Figure 8) are partially included in the average according to their temporal overlap with the report interval marked in blue as follows:…”

“…Tis condition is hardly satisfed for any real signal. Nevertheless, the estimation error in dynamic conditions is drastically improved compared to the fp-method [21]. Te partial period method, therefore, practically solves the temporal alignment problem.…”

“…From the academic side, the electrical data recorder (EDR) has been developed as a device for high-resolution time series acquisition in low-voltage distribution grids. It provides UTC-time-stamped frequency estimates up to ten times per second and allows long-term storage of full voltage and/or current waveforms for further analysis [18][19][20][21]. Te frequency is estimated using the well-known zero-crossing technique that enables straightforward and fast processing and is widely developed by scientists [22][23][24][25].…”