Optimal voltfivar curve setting of a smart inverter for improving its performance in a distribution system

Abstract

We propose an algorithm to set the parameters of voltfivar curves to improve the performance of distributed generation. Specifically, we optimally set the voltfivar curves of the smart inverter for proper control of the distributed generation output. To improve the overall distribution system performance, we consider the minimization of voltage deviation, system loss, and peak of reactive power in an objective function, thereby providing optimal voltfivar curve parameters. The proposed algorithm overcomes various limitations of existing studies. First, we use distribution system factors in a multiobjective optimization function to adjust voltfivar curve parameters that deviate from the default settings. Second, we consider the service transformers that affect the system voltage according to the photovoltaic generation output in the test model during optimization. Third, we analyze the system improvement according to the number of parameters to be optimized. Fourth, we analyze the implementation of the optimized voltfivar curve according to the practical periods when the smart inverter settings can be updated. Fifth, we evaluate different suitable voltfivar curves for multiple photovoltaic generators grouped using clustering. Using the proposed algorithm, the distribution system operator can set the optimal voltfivar curve according to the system conditions and requirements. We conducted simulations of the proposed method using OpenDSS, a quasistatic time-series simulation, on a test model refiecting the characteristics of a South Korean distribution system. The simulation results confirm that the overall system performance increases when the optimal voltfivar curve settings obtained from the proposed algorithm are used.