**1. Introduction**

#### *1.1. Literature Survey*

The incorporation of distributed power sources in the EDS can support the increasing load demands. To satisfy the increasing load demands, an extremely thorough comparison and assessment has been performed on exploring the potentiality of the distributed energy sources, including the wind and solar energies [1,2]. The EDS is the combination of electrical loads and Distributed Generation (DG) (especially, WTG and SPV) integrated with electrical storage system (namely BSS) [3]. In this regard, several comprehensive studies are available on sustainable energy production and management. The state policies, renewable energy plants, and the development of renewable energy sources including solar energy, wind energy, small hydroelectric energy, biomass energy, tidal energy, and geothermal energy have been analyzed for different states of India [4–6]. As the energy crisis deepens day by day, the EDS accompanied by RESs is a better solution and also it acts as a complement to the central power grid system [7]. Therefore, a study on renewable energy potential has been performed for five countries, namely China, Iceland, India, Sweden, and the United States of America. The strengths, weaknesses, opportunities, and threats related to green energy generation and use have been reviewed for these countries using a SWOT analysis [8,9]. Sometimes an arrangement including the battery storage is needed due to high penetration of renewable resources into an electrical network to fulfill the load demands [10,11]. Thus, integration of BSS in the distribution system prevails as a better solution for obtaining a steady power output, especially from WTG and SPV owing to the uncertainties involved in the energy harvesting sources such as wind speed [1], solar irradiation, and ambient temperature [12]. Therefore, it is a requisite to determine the siting(s) and sizing(s) of WTG, SPV, and BSS. The system reliability, stability, and power quality are thus, improved substantially. Therefore, to obtain improvements in system's attributes, the multi-objective optimization methods for problems including operational cost, siting and sizing of distributed energy resources (DERs), Carbon Dioxide (CO2) emission, total power loss, voltage deviation, demand-side management, charging-discharging of BSS, total harmonic distortion, and system reliability are also established [13–17].

Improvement in network reliability is observed when congestion management algorithms are implemented to identify the transmission line congestion [18]. The DGs and BSSs are scheduled optimally to alleviate this transmission line congestion. A two-step optimization approach is used for solving the congestion problem [19]. In this optimization method, the optimum location and the size of the SPV array are observed, and then the BSS size with location is determined for accomplishing further reduction in electrical losses and voltage deviation. The authors in [20] have proposed an index to obtain the optimal siting of DGs in EDS. This index is implemented to resolve the multiple problems, including total ELM, ENS, and voltage deviation. Another objective, namely loss of yearly energy minimization, is observed through the integration of DERs-based DGs and network reconfiguration [21]. Furthermore, a novel two-stage stochastic programming is proposed, and the uncertainty considerations together with the load variation are also studied especially for wind energy and solar power generation [22]. In this method, the total cost is reduced by incorporating BSS into the EDS and by considering the demand response programs in planning. Simultaneously, the enhancement of the power system reliability is achieved due to the obtained optimal BSS size and location. The reliability improvement and reduction in network losses are also observed using compound co-optimization strategic plan [23]. The reliability indices such as expected ENS, EIR, LOLE, and LOLP, are defined in the co-optimization strategy. Furthermore, a moth-flame optimization [24], Olympic games ranking process [25], firefly algorithm [26], lightning search algorithm [27], crow search optimization [28], and an improved variant PSO [29] techniques have been implemented and discussed in the literature so as to obtain the optimal site, optimal size, optimal parameters of DGs, and ELM.

The RA provides a better evaluation of any power system's performance [30]. For assessing the power system's reliability, some indices have been mentioned in the available literature. These indices are categorized into load-based and system-based indices. The indices values decrease if the ageing of the sub-components is considered [31]. Reliability is considered to be a primary requirement in the designing phase of EDS. Thus, the optimal siting and optimal sizing of RESs for further RA have also been considered. To fulfill the RA in EDS [15], has introduced a restoration strategy for ENS calculation. The optimization of reliability indices has been considered in [20,23], and the improvement in the system's reliability is observed.
