Probabilistic Approach to Determine Penetration of Hybrid Renewable DGs in Distribution Network Based on Voltage Stability Index

Abstract

An increase in the applications of renewable-based energy resources in the radial distribution network has led to many uncertainties in the existing system which affects the stable operation of the power systems. The issues regarding the generation uncertainty associated with wind energy and photovoltaic (PV) systems along with load demand uncertainties are considered in this research for the evaluation of the maximum penetration level of renewable energy resources. The nodes which are less voltage stable are considered as the most suitable locations for distributed generations (DGs) placement from voltage stability viewpoint. For identification of DGs locations, a voltage stability index–continuous power flow-based algorithm has been proposed. To analyze the effect of large penetration level of wind and PV on voltage profile, power losses and system voltage stability of the radial distribution network, a probabilistic-based approach has been adopted. It is observed from simulation results that the penetration level limit depends upon the type of DGs connected to the radial distribution network. Usually the integration of DGs reduces the power losses in the network; however, as penetration level increases, the power losses begin to increase. The detailed mathematical model of wind and PV sources has been utilized. The Hong’s 2m + 1 point estimation method combined with Cornish–Fisher expansion has been adopted in this paper for probabilistic studies. The effectiveness of the proposed method has been validated through IEEE 33 and 69 node radial distribution test network for various scenarios. The results obtained are verified and compared with benchmark Monte Carlo simulation technique.