Keywords: PV plant, smart-inverter, distribution grid, voltage regulation, disconnection of inverter from distribution grid


The article considers the operation of a photovoltaic (PV) plant connected to the distribution grid (DG) via a smart inverter, which has the function of stabilizing the output voltage by regulating the reactive power. The electric model of the system “PV plant - radial DG - distribution substation (DSS)” is constructed and the corresponding numerical calculations of nonlinear equations system in the power flow representation are performed. The paper analyzes the influence of the inverter output power on the voltage at the point of
common connection (PCC) to the DG under the setting of different characteristics of the network equipment, namely: the parameters of step-up transformers and the power lines capacity. In our work the monitoring data obtained by PV inverters for which disconnections from DG are observed at high levels of solar radiation were used. It was found that the transformers power does not significantly affect the PCC overvoltage if the transformers have the appropriate power, and their electrical insulation is in good condition. The same applies to power losses in the distribution line. It is shown that the main role in exceeding the allowable output voltage of an inverter connected to DG is played by electrical losses in the connecting wires PCC to the step-up transformer. The limit values of the length of the connecting line for different types of wires widely used for low-power PV plants as well as for different types of network equipment DG and DSS are obtained.

The possibility of voltage regulation at PCC by smart-inverter reactive power modulating is analysed. Simulation of inverter voltage regulation is performed considering the role of grid equipment (transformers and feeders). Estimates of the influence degree of dynamic inverter regulation as well as the dependence of the regulation effect on the connecting line length and on the step-up transformer power are obtained. It is shown that inverter regulation is more effective on decreasing voltage than on increasing, and that the regulating effect is more pronounced the greater the length of the connecting line.


P. M. S. Carvalho, P. F. Correia, and L. A. F. Ferreira, “Distributed reactive power generation control for voltage rise mitigation in distribution networks”, IEEE Trans. Power Syst., vol. 23, no. 2, pp. 766–772, 2008.

M. A. Eltawil, and Z. Zhao, “Grid-connected photovoltaic power systems: Technical and potential problems — A review”, Renewable and Sustainable Energy Reviews, vol. 14, pp. 112–129, 2010.

M.-S. Kim, R. Haider, and G.-J. Cho, “Comprehensive Review of Islanding Detection Methods for Distributed Generation Systems”, Energies, 12, 837, 2019. doi:10.3390/en12050837.

A. Y. Gaevskii, V. V. Bodnyak, and A. N. Gayevskaya, “Analysis of the monitoring data of PV-inverter connected to distribution grid”, (in Russian), Int. Sci. J. of Alternative Energy and Ecology (ISJAEE), No 31-36, pp. 279–284, 2018.

IEC 61727:2004. Photovoltaic (PV) systems – Characteristics of the utility interface. [Online]. Available:

DIN V VDE V 0126-1-1/A1 (VDE V 0126-1-1/A1):2012-02. Selbsttätige Schaltstelle zwischen einer netzparallelen Eigenerzeugungsanlage und dem öffentlichen Niederspannungsnetz. [Online]. Available: ttps://

G. Chicco, J. Schlabbach, and F. Spertino, “Experimental assessment of the waveform distortion in grid-connected photovoltaic installations”, Solar Energy, vol. 83, pp. 1026–1039, 2009.

E. Liu, and J. Bebic, “Distribution System Voltage Performance Analysis for High-Penetration Photovoltaics”, Report NREL/SR-581-42298, February 2008. [Online]. Available:

F. Delfino, R. Procopio, M. Rossi and G. Ronda, “Integration of large-size photovoltaic systems into the distribution grids: a P–Q chart approach to assess reactive support capability”, IET Renew. Power Gener., vol. 4, Iss. 4, pp. 329–340, 2010.

A. Y. Gaevskii, and I. E. Golentus, “Stabilization of the grid voltage by reactive power compensating by PV plant inverters'', (in Russian), in Proc. XIV International Conference "Vidnovliuvana Energetyka XXI stolittia", Crème, 2013, pp. 243–245.

E. Ghiani, and F. Pilo, “Smart inverter operation in distribution networks with high penetration of photovoltaic systems”, J. Mod. Power Syst. Clean Energy, N3 (4), pp. 504–511, 2015. DOI 10.1007/s40565-015-0165-4.

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How to Cite
GaevskiiО., GaevskaА., Bodnyak, V., & Konovalov, M. (2022). THE PROBLEM OF OPTIMIZATION OF HYBRID ENERGY SYSTEM ACCORDING TO THE LEVEL OF DISPERSION OF GENERATED POWER. Vidnovliuvana Energetyka, (1(68), 27-36.
Complex Problems of Power Systems Based on Renewable Energy Sources