Reliability constrained planning and sensitivity analysis for solar-wind-battery based isolated power system

Isolated hybrid power systems have emerged as a practical substitute to grid extension for electrification of remote areas. Increased penetration of renewable energy sources (RES) such as solar and wind can commendably cut down system operating costs but can create reliability issues owing to their unpredictable nature. Thus, an effective storage integration is needed in order to ensure reliability standards. This paper presents reliability and cost-based sizing of solar-wind-battery storage system for an Isolated hybrid power system (IHPS). In order to analyze system reliability, dual reliability indices, Probability of risk and Probability of health have been used in this work. These reliability indices provide a better assessment of system reliability when RES are being used. The objective function for optimal planning is based on minimization of Total life cycle cost (TLCC). Considering variable nature of solar and wind sources, modelling of solar irradiance and wind speed has been done using Beta and Weibull probability density functions (pdf) respectively. The hardware availability modelling of generators has been done based on their respective forced outage rates. Monte-Carlo simulation (MCS) has been used for conducting reliability evaluation. For solving optimal sizing problem, a nature inspired algorithm called as Particle Swarm Optimization (PSO) has been employed. Sensitivity analyses are performed by studying the effect of addition/removal of RES-based generators and storage units on system reliability. In order to assess the additional investment required to improve reliability standards, a new index termed as Incremental cost of reliability has been used in this paper. A case study has been carried out for an IHPS located in Jaisalmer, India. The results have been suitably analyzed to facilitate a deeper insight into system planning. © 2020, Aalborg University press. All rights reserved.