Considering the strong influence of distributed generation (DG) in electric distribution systems and its impact on network voltage losses and stability, a new challenge has appeared for such systems. In this study, a novel analytical algorithm is proposed to distinguish the optimal location and size of DGs in radial distribution networks based on a new combined index (CI) to reduce active power losses and improve system voltage profiles. To obtain the CI, active power losses and voltage stability indexes were used in the proposed approach. The CI index with sensitivity analysis was effective in decreasing power losses and improving voltage stability. Optimal DG size was determined based on a search algorithm to reduce active power losses. The considered scheme was examined through IEEE 12-bus and 33-bus radial distribution test systems (RDTS), and the obtained results were compared and validated in comparison with other available methods. The results and analysis verified the effectiveness of the proposed algorithm in reducing power losses and improving the distribution system voltage profiles by determining the appropriate location and optimal DG size. In IEEE 12 and 33 bus networks, the minimum voltage increased from 0.9434 p.u and 0.9039 p.u to 0.9907 p.u and 0.9402 p.u, respectively. Additionally, the annual cost of energy losses decreased by 78.23% and 64.37%, respectively.

The integration of gas and electricity networks has emerged as a promising approach to enhance the overall flexibility of energy systems. As the transition toward sustainable and decarbonized energy sources accelerates, the seamless coordination between electricity and gas infrastructure becomes increasingly crucial. This paper presents a comprehensive review of the state-of-the-art research and developments concerning the flexibility in the operation of low-carbon integrated gas and electricity networks (IGENs) as part of the whole system approach. Methods and solutions to provide and improve flexibility in the mentioned systems are studied and categorized. Flexibility is the system’s ability to deal with changes and uncertainties in the network while maintaining an acceptable level of reliability. The presented review underscores the significance of this convergence in facilitating demand-side management, renewable energy integration, and overall system resilience. By highlighting the technical, economic, and regulatory aspects of such integration, this paper aims to guide researchers, policymakers, and industry stakeholders toward effective decision-making and the formulation of comprehensive strategies that align with the decarbonization of energy systems.

Many real-world power systems operate near voltage stability limits due to rising power demands, limited generation sources, and delays in development projects. Therefore, conducting online voltage stability assessments of power systems is crucial to ensure stable system operation. Various indices have been proposed in recent years to assess voltage stability in this context. One of the main challenges of these indexes for implementation in real-world power systems is their formulation with two-bus and single-line systems and their generalization to multi-bus and multi-line systems, which makes them non-rigorous. In formulating the existing indexes that use the concept of voltage sensitivity to active power, the effect of the lines from which the bus receives active power can be seen separately in evaluating bus voltage stability. At the same time, for accurate evaluation, the set of lines and the received power of all lines should be considered together in formulating the index. To meet this challenge, a new real-time index for voltage stability assessment is introduced in this paper. Furthermore, the effect of distribution systems in voltage stability is investigated in this study using simultaneous modeling transmission and distribution systems. The test results of the proposed index on the power system of the 3-bus system and the IEEE 14, 30, and 118 bus systems show its superior performance compared to the existing index. Specifically, to increase the apparent power loading in the 118-bus system, the maximum error of the proposed index is 3.37%. Meanwhile, for index P and index L, the maximum error is 29.6% and 30.75%, respectively. Finally, the results show that modeling the distribution system in the 3 and 118 bus systems reduces the maximum active power loading by 35.21% and 59.27%, respectively.

The widespread adoption of EVs can alleviate strain on power grids and enhance power quality in multiple ways. First, the integration of EVs enables better utilization of renewable energy sources by serving as mobile energy storage units. During periods of peak renewable energy generation, excess power can be stored in EV batteries, reducing curtailment and maximizing resource efficiency. Second, smart charging infrastructure and vehicle-to-grid (V2G) technology allow EVs to interact with the grid intelligently. Through V2G systems, EVs can supply power back to the grid during high-demand periods, effectively functioning as decentralized energy storage units. This bidirectional energy flow helps stabilize voltage and frequency fluctuations, ultimately improving overall power quality. Furthermore, EVs can facilitate load balancing by enabling charging during off-peak hours, spreading the electricity demand more evenly throughout the day. This approach minimizes the strain on the grid during peak times and enhances system stability. In summary, electric vehicles not only reduce emissions and promote sustainability but also contribute to optimizing power generation, storage, and distribution, leading to a more resilient and higher-quality power supply. In this chapter, the impact of electric vehicles on improving the quality of power in the voltage and frequency sections has been investigated.