## 5 Conclusions
These factors must be considered in the design of the controller to mitigate the effects of this undesirable phenomenon. Within the analyzed topologies, it should be noted that the H5 topology provides a good compromise in terms of reduction in the leakage current, number of components, and current quality. This topology and other schemes, connect the negative terminal of the PV to the neutral point of the grid using passive components and switches. Furthermore, another commonly used strategy is the disconnection of the AC side and the PV during free wheeling times of inductors in current-source inverters. Finally, it was highlighted that the modulation strategy is a critical factor in reducing the leakage current. Bipolar modulations offer the greatest reduction of this current in PV applications. However, its high complexity makes it difficult to use. Otherwise, the unipolar modulation strategy is widely used for its simplicity. In the works reviewed in this paper, only one of seventeen articles presented the bipolar modulation. Conceptualization, A.A.E.-B. and A.A.-D.; Methodology, A.A.E.-B. and A.A.-D; Writing--original draft preparation, A.A.E.-B. ; Writing--review and editing, A.A.E.-B., A.A.-D, G.M.-B and J.R.-R.; Supervision, J.R.-R. and G.M.-B. All authors have read and agreed to the published version of the manuscript. This research received funding from PRODEP and CONACYT. The authors declare no conflict of interest. The following abbreviations are used in this manuscript: \begin{tabular}{l l} RE & Renewable Eneregy \\ PV & Photovoltaic \\ CSI & Current Source Inverter \\ VSI & Voltage Source Inverter \\ ZSI & Impedance Source Inverter \\ DC & Direct Current \\ AC & Alternating Current \\ SAPV & Stand-Alone Photovoltaic \\ CMV & Common Mode Voltage \\ RMS & Root Mean Squared \\ CM & Common Mode \\ DC & Direct Current \\ AC & Alternating Current \\ CPV & Concentrator Photovoltaics \\ MPP & Maximum Power Point \\ \end{tabular} \begin{table}
\begin{tabular}{c c c c c} \hline \hline \multicolumn{2}{c}{**Image**} & \multicolumn{2}{c}{**Image**} & \multicolumn{2}{c}{**Image**} \\ \hline \multirow{6}{*}{Over voltage Sage 1} & Default & 0.2 & 230V+15\% \\ \cline{2-5}  & CZ & 0.2 & 230V + 15\% \\ \cline{2-5}  & DE & 0.2 & 230V + 10\% \\ \cline{2-5}  & DK & 40 & 230V + 10\% \\ \cline{2-5}  & ES & - & 230V + 10\% \\ \cline{2-5}  & FR & 0.2 & 230V + 15\% \\ \cline{2-5}  & GB & 1.5 & 264 \\ \cline{2-5}  & IT & 0.1 & 230V + 20\% \\ \hline \multirow{6}{*}{Under voltage} & Default & 1.5 & 230V-15\% \\ \cline{2-5}  & CZ & 0.2 & 230V - 15\% \\ \cline{2-5}  & DE & 0.2 & 230V - 15\% \\ \cline{2-5}  & DK & 10 & 230V - 10\% \\ \cline{2-5}  & ES & - & 230V - 15\% \\ \cline{2-5}  & FR & 0.2 & 230V - 15\% \\ \cline{2-5}  & GB & 1.5 & 207 \\ \cline{2-5}  & IT & 0.2 & 230V - 20\% \\ \hline \hline \end{tabular}
\end{table} 
Table 10: Comparison of voltage requirements standards for LV PV systems. \begin{table}
\begin{tabular}{c c c} \hline \hline  & **Max. Clearance Time (sec)** & **Trip Setting** \\ \hline Default & 0.5 & 51 Hz \\ \hline CZ & 0.2 & 50.5 Hz \\ \hline DE & 0.2 & 51.5 Hz \\ \hline DK & 0.2 & 53 Hz \\ \hline ES & ND & 50 Hz + 2\% \\ \hline FR & 0.2 & 50.5 Hz \\ \hline GB & 0.5 & 50.5 Hz \\ \hline IT & 0.1 & 51 Hz \\ \hline Default & 0.5 & 47 Hz \\ \hline CZ & 0.2 & 49.5 Hz \\ \hline DE & 0.2 & 47.5 Hz \\ \hline DK & 0.2 & 47 Hz \\ \hline ES & ND & 50 Hz-2\% \\ \hline FR & 0.2 & 49.5 Hz \\ \hline GB & 0.5 & 47 Hz \\ \hline IT & 0.1 & 49 Hz \\ \hline \hline \end{tabular}
\end{table} 
Table 6: Clearance time for frequency deviations. \begin{table}
\begin{tabular}{c c c c c} \hline \hline \multicolumn{1}{c}{**IEEE 1574**} & \multicolumn{2}{c}{**IEC 61727**} & \multicolumn{2}{c}{**VDE-AR-N 4105**} \\ Frequency range (Hz) & Disc. (sec) & Frequency range (Hz) & Disc. (sec) \\ \hline \(59.3<f<60.5\) & 0.16 & 49 \(<f<51\) & 0.2 & 47.5 \(<f<51.5\) & 0.10 \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Frequency deviations and disconnection time.