Abstract

The integration of solar photovoltaic power with Battery Energy Storage System (BESS) has recently increased. The deployment of a battery energy storage system for the photovoltaic (PV) application has been increasing at a fast rate. Since PV technology was established and launched it used a DC to AC inverter to convert direct current to alternative current for grid connection, this units which consists of electronic elements has poor reliability aspect and since PV systems use large amount of these inverters, the total system reliability is low. In our research we propose a new configuration for reliability analyses of converting direct current to alternative current using Motor Generator Pair (MGP). MGP’s reliability is higher from standard inverter, moreover, one MGP replacing a dozen inverters which improves the total system reliability. In particular, this research presents reliability analysis of two different configuration of systems for reliability analysis and comparing them. To find the reliability indices, an analysis was conducted using a Multi-State System (MSS) using Markov processes, a Universal Generating Function (UGF) and a z-transform. The results show that there is a significant improvement in reliability indices for the MGP alternative. To find the Loss of Load Probability (LOLP) parameter, an analysis was conducted for eleven different values of load factors, the results demonstrated a significant improvement in system reliability achieved by integrating an energy storage system. These findings demonstrate the effectiveness of the storage system in optimizing a photovoltaic system, especially in improving reliability in scenarios with low load factors. For the first proposed system with standard 25 inverters without BESS the obtained LOLP is 0.5750 for standard load L1while with BESS LOLP is 0.0401, for the second proposed system that consist of MGP the obtained LOLP without BESS is 0.5666 while the LOLP with BESS is 0.038. These improvements in LOLP reflects the role of the BESS in improving the reliability of the system.