Proportional reactive power sharing among the distributed generators (DGs) is still a challenge in an islanded microgrid. The disparity in output voltage of each DG is the main cause of the error in reactive power sharing in DGs. The output voltage difference of DGs is caused by unequal line impedances and connected local loads. In order to reduce the error in reactive power sharing among the DGs, a Robust Volt-VAr control scheme (RVVCS) with an adaptive nominal voltage is proposed in this study. Since the suggested strategy is entirely decentralized, it does not need knowledge of feeder impedance or network configurations. Also, it does not require any communication link or optimization technique. The technique proposed is tested on several network configurations, including various loads, radial networks, reconfigured networks, and mesh networks, and is found satisfactory in each case. In one of the many cases presented in this study, with \(n_q\) = \(3e^{-4}\) V/VAr, \(\beta \) = 0.2, \(\beta _{add}\) = 0.002 and local as well as common load is connected, the suggested RVVCS minimises the error in reactive power output of \(DG_1\), \(DG_2\) and \(DG_3\) to (42.68%, \(-\) 8.92%, \(-\) 33.82%), respectively, compared to the error obtained in RDCS (72.21 %, \(-\) 15.61%, \(-\) 56.6%), SADCS (72.6%, \(-\) 16%, \(-\) 56.6%) and CDCS (243.74%, \(-\) 69.87%, \(-\) 173.87%). A similar reduction pattern in reactive power output is also observed in all the case studies performed in this research. The stability of the proposed strategy is investigated in terms of eigenvalue analysis. The practicability of the proposed technique is validated in time-domain simulation in MATLAB/Simulink.
