## 4 Conclusions  
From the conducted examination of different cases, it can be seen that the voltage support by means of reactive power is not an effective solution in LV grids with high penetration level of renewables. Besides the bigger amount of curtailed energy, the grid performance is also deteriorated due to the additional reactive power.  
The mitigation of the negative-sequence voltage component alone, is not sufficient to increase the penetration level of DERs. The presented results showed too small improvement in energy exchange and grid performance compared to the case where both sequence components are impacted at the same value of the damping conductance (\(g_{d}=50\) p.u.). From the presented results it can be seen also that the overall LV grid losses are slightly deteriorated. In conclusion, in order to increase the penetration level of DERs and improve the grid performance the zero-sequence component must be mitigated. Excellent results are shown by the modified three-phase damping control strategy. Even low values of the damping conductance of 3 p.u. to 10 p.u. are sufficient to increase the annual energy injection, mitigate the voltage unbalance, prevent overvoltages and decrease the grid losses. The conducted simulation at high \(g_{d}\) values showed that the three-phase damping control strategy is able to maintain the voltage levels even better; it maximizes the energy injection compared to the classical positive-sequence variable power factor control strategy with 13.4 MWh/a and reduces the grid losses with about 7 MWh/a. Based on the presented simulation case studies, it can be concluded that the three-phase damping control strategy has a very good potential to provide ancillary services to the distribution system operator.  
[PERSON], [PERSON], and [PERSON] have written the text and perfomed the simulations. [PERSON] has provided valuable inside regarding the ancillary services in Fluvius. [PERSON] have provided reviews and editing of the proposed ideas and also supervision of the process. All authors have read and agreed to the published version of the manuscript.  
The work of [PERSON] is conducted in the frame of project Interreg 2 Seas project--Ports Energy and Carbon Savings (PECS) (period 2014-2020). The project is co-funded by the European Regional Development Fund under subsidy contract No 2S01-020. Additional financing is also provided by the Dutch Provinces of North-Holland and South-Holland. The work of [PERSON] in this paper is conducted in the frame of the ROLECS project (ICON HBC.2018.0527). This project is financed by Flanders Innovation and Entrepreneurship (VLAIO).  
The authors would like to express their gratitude to [PERSON], who is with a Slovenian DSO called Elektro Goreniska. He was very kind to provide all necessary data of the low voltage grid, which is used to perform the analyses in this article.  
The authors declare no conflicts of interest.  
The following abbreviations and symbols are used in this manuscript.  
\begin{tabular}{l l l l} APF & Active Power Factor & \(v_{g}\) & rms value of the grid voltage \\ BESS & Battery Energy Storage System & \(v_{\text{cpb}}\) & constant power band voltage \\ CHP & Combined Heat and Power & \(v_{g,\text{min}}\) & minimum grid voltage \\ DER & Distributed Energy Resources & \(v_{g,\text{max}}\) & maximum grid voltage \\ DG & Distributed Generation unit & \(p_{\text{ac}}\) & injected ac power \\ DSO & Distribution System Operator & \(p_{\text{dc,nom}}\) & nominal power of the primary source \\ \end{tabular}