# Impacts of Lightning-Induced Overvoltage on a Hybrid Solar PV-Battery Energy Storage System
## 6 Conclusions  
Throughout this paper, the impacts of different lightning current amplitudes, lightning strike locations, and cable lengths on hybrid solar PV-battery energy storage systems have been analyzed. Although one can logically infer that lightning-induced overvoltage is increased with increased lightning current amplitude, it was indeed the aim of this paper to quantify the results based on several parameters, such as the cable length and distance from the lightning source. The results obtained allowed us to quantify this sought-after information, particularly related to strike distance and cable length, which are often discussed in international working groups such as International Council on Large Electric Systems Working Group Committees 4.44 (CIGRE WG C4.44) on Electromagnetic Compatibility (EMC) for Large Photovoltaic Systems. In this work, the differences in cable length did not have much impact on the lightning-induced overvoltage, since the voltage drop was too small due to the cable lengths being short. It is quite interesting that the effects of cable length were much more significant in the case of a direct strike [11]. Nevertheless, since the effects of lightning-induced voltages on the hybrid solar PV-battery energy storage system were highly dependent on the abovementioned factors, an insulation coordination study is crucially needed to ensure the security of grid-connected systems, as well as to assign and coordinate appropriate protection schemes. This work is in line with the current direction of the CIGRE Working Group C4.44 on EMC for Large-Scale Solar Systems, which is in the midst of developing its technical brochure. Overall, this study has spurred some ideas on the requirements for lightning protection system (LPS) installations, i.e., how the appropriate protection scheme should be coordinated and the numbers and ratings of surge protection devices for hybrid solar PV-battery energy storage systems. This is due to the fact that the possible risk posed by lightning strikes, as well as the requirements for lightning protection, are crucial steps in designing a lightning protection system. Essentially, a lightning protection system is a must-consider item for system protection. Therefore, the results and analyses presented in this paper will be useful information and sources for other researchers, as well as a basic guideline for conducting future research on insulation coordination in hybrid solar PV-battery energy storage systems. Conceptualization, N.I.A. and M.Z.A.A.K. ; methodology, N.I.A. ; software, N.I.A. and M.H.R. ; validation, N.I.A. ; formal analysis, N.I.A. ; investigation, N.I.A., Z.A. and M.Z.A.A.K. ; resources, N.I.A. and N.H.Z. ; data curation, N.I.A. ; writing--original draft preparation, N.I.A. ; writing--review and editing, Z.A. and M.Z.A.A.K. ; visualization, N.I.A. ; supervision, Z.A., M.Z.A.A.K. and M.O. ; project administration, Z.A., M.Z.A.A.K. and M.O. ; funding acquisition, Z.A., M.Z.A.A.K. and M.O. All authors have read and agreed to the published version of the manuscript. This research and APC were funded by Ministry of Higher Education, Fundamental Research Grant Scheme (FRGS) scheme, grant number FRGS/1/2018/TK07/UNITEN/02/5, and  
Figure 18: The lightning-induced overvoltage profile when the lightning is induced at an observation point of 10 m, with the lightning-induced overvoltage values measured at every observation point (spaced 2 m apart, for a total cable length of 20 m; I0 = 19 kA, x = 0, d = 50 m, v = 1.2 \(\times\) 10\({}^{-8}\) m/s). also the Building Opportunity Leading Dreams (BOLD) publication fund provided by Universiti Tenaga Nasional. **Institutional Review Board Statement**: Not applicable. **Informed Consent Statement**: Not applicable. **Data Availability Statement**: Not applicable. **Acknowledgments**: The authors would like to express their sincere gratitude to the Ministry of Higher Education, Institute Power Engineering, and Building Opportunity Leading Dreams (BOLD) Scholarship of Universiti Tenaga Nasional (UNITEN).