# IpDFT-Tuned Estimation Algorithms for PMUs: Overview and Performance Comparison
## 5 Experimental Results in a Practical Case Study  
To validate the simulation-based performance comparison reported above in a case study of practical interest, 1000 2-cycle, 4-cycle, 6-cycle and 8-cycle data records of a waveform generated by a function generator Agilent 33220A were collected through a 12-bit data acquisition system (DAQ) NI6023E. Each generated waveform exhibits nominal normalized amplitude, initial phase chosen at random in the range [0, 2\(\pi\)], fundamental frequency within [47 Hz, 52 Hz] and a Total Harmonic Distortion (THD) of about 9.4%. The \begin{table}
\begin{tabular}{c c c c c c c c c c} \hline \hline  & & & & & & & & & & \\ \hline \multirow{2}{*}{\begin{tabular}{c} **Estimation** \\ **Algorithm** \\ \end{tabular} } & \multirow{2}{*}{\begin{tabular}{c} **No.** \\ **Cycles** \\ \end{tabular} } & \multirow{2}{*}{**TVE**} & \multirow{2}{*}{\(|\)FE\(|\)} & \multirow{2}{*}{\(|\)**IRFE\(|\)} & \multirow{2}{*}{\(|\)**Phasor** **Resp.**} & \multirow{2}{*}{\(\begin{array}{c} **Freq.** \\ **Resp.** \\ **Time** \\ \end{array}\)} & \multirow{2}{*}{\(\begin{array}{c} **ROCOF** \\ **Resp.** \\ **Time** \\ \end{array}\)} & \multirow{2}{*}{\(\begin{array}{c} **Delay** \\ **Time** \\ \end{array}\)} \\ \hline \multirow{2}{*}{\begin{tabular}{c} IpDFTc \\ \end{tabular} } & 2 & C & NC & C & C & C & C & C & C \\ \cline{2-10}  & 4 & C & C & C & NC & C & C & C & C \\ \hline Tuned & 2 & C & NC & NC & C & C & C & C \\ \cline{2-10} TWLS & 4 & C & C & C & C & C & C & C & C \\ \hline DCF with & 2 & C & NC & NC & C & NC & NC & C \\ \cline{2-10} LSF & 4 & C & C & C & C & C & NC & C \\ \hline DCF with & 2 & C & NC & NC & C & C & C & C \\ \cline{2-10} STD & 4 & C & NC & NC & NC & NC & C & C \\ \hline \hline \end{tabular} \begin{tabular}{c c c c c c c c c} \hline \hline \multirow{2}{*}{\begin{tabular}{c} **Estimation** \\ **Algorithm** \\ \end{tabular} } & \multirow{2}{*}{\
\begin{tabular}{c} **No.** \\ **Cycles** \\ \end{tabular} } & \multirow{2}{*}{**TVE**} & \multirow{2}{*}{\(|\)FE\(|\)} & \multirow{2}{*}{\(|\)**IRFE\(|\)} & \multirow{2}{*}{\(|\)**Phasor** **Resp.**} & \multirow{2}{*}{\(\begin{array}{c} **Freq.**\\ **Resp.** \\ **Time** \\ \end{array}\)} & \multirow{2}{*}{\(\begin{array}{c} **ROCOF** \\ **Resp.** \\ **Time** \\ \end{array}\)} & \multirow{2}{*}{\(\begin{array}{c} **Delay** \\ **Time** \\ \end{array}\)} \\ \hline \multirow{2}{*}{
\begin{tabular}{c} IpDFTc \\ \end{tabular} } & 6 & C & NC & C & C & C & C & C \\ \cline{2-10}  & 8 & NC & C & C & C & C & C & C \\ \hline Tuned & 6 & NC & NC & C & C & C & C & C \\ \cline{2-10} TWLS & 8 & C & C & C & C & C & C & C \\ \hline DCF with & 6 & C & NC & NC & C & C & C & C \\ \cline{2-10} LSF & 8 & C & C & C & C & C & C & C \\ \hline DCF with & 6 & C & NC & NC & C & C & C & C \\ \cline{2-10} STD & 8 & C & NC & NC & C & C & C & C \\ \hline \hline \end{tabular}
\end{table} 
Table 8: Overall comparison between the IpDFT-tuned estimation algorithms under study in the _P Class_ (a) and _M Class_ (b) PMU testing conditions reported in the IEEE/IEC Standard 60255-118-1:2018. Letter C stands for “full compliance” with all the limits reported in the testing conditions considered in Section 3 for RR = 50 frame/s, whereas “not compliant” (NC) means that at least one of the Standard limits is exceeded. The cells related to the best performing algorithm are shaded. THD level purposely slightly exceeds the limit reported in the Standard EN 50160:2010 [33]. In particular, according to that Standard, the range [47 Hz, 52 Hz] shall never be exceeded, although in practice the system frequency is required to lie within [49.5 Hz, 50.5 Hz] for 95% of the time of a week. The THD instead must be not greater than 8% with the first 25 harmonics that have to be smaller than a value ranging from 0.5% to about 6% of the fundamental, depending on the harmonic order. In the current study, just the harmonics from the 2 nd to the 7 th ones are included. Their amplitude is equal to 2%, 5%, 1%, 6%, 0.5% and 5% of the fundamental, respectively.