Optimal sizing of photovoltaic distributed generators in a distribution system with consideration of solar radiation and harmonic distortion

This paper presents a probabilistic approach to design an optimal size of photovoltaic distributed generator (PV-DG) in a distribution system. A steady-state voltage stability index is applied to select PV-DG locations. The objective of the proposed technique is to minimize average system active power losses, while considering power quality constraints (i.e., voltage regulation, total harmonic voltage distortion, total demand distortion and harmonic currents). Monte Carlo simulation is applied to acquire solar radiations, ambient temperatures, load demands and substation voltages. The proposed technique is tested on an actual 51-bus medium voltage distribution system in Thailand. From simulations, there is a different solution between selecting the optimal size of PV-DG from with and without considering background harmonics. Also in realistic cases, PV-DGs may improve voltage regulation and decrease losses in distribution systems; however, increase total harmonic voltage distortion values.

► We design an optimal size of PV-DG based on a probabilistic approach.
► We consider the stochastic variables of both generation and load.
► This technique is based on actual hourly solar radiation and ambient temperature.
► The optimal PV-DG size can be determined taking into account background harmonics.
► High background harmonic may affect the optimal size of PV-DG.