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The growing demand for electric power and the need for an energy transition that contributes to the reduction of global greenhouse gas emissions have driven the development of various energy generation, storage, and offset technologies. These technologies are known as distributed energy resources. Their integration into distribution power systems not only contributes to improving operating aspects, but also allows supplying electricity to areas that do not have access to large-scale power systems. Therefore, the integration and management of these resources has become a topic of interest, and several studies seek to optimize their impact on technical, economic, and environmental aspects. However, this optimization poses specific challenges related to the type and number of variables related to the operation of a distribution power system. This review article aims to describe the main challenges posed by three-phase AC three-phase distribution power systems under scenarios involving the integration of distributed energy resources. In addition, it presents some approaches proposed by different authors to improve the technical, economic, and environmental aspects of power grids. It can be stated that the strategies presented in the literature fail to consider scenarios that simultaneously integrate different types of technologies and optimize them while following a multi-objective approach and considering three-phase systems in a context of variable generation and demand. Therefore, future work in this field should address these aspects in a holistic manner, taking into account the computation efforts and processing times required by intelligent algorithms.

This study proposes a compact four-port multiple-input multiple-output (MIMO) antenna system to operate within a frequency range of 3.2–5.75 GHz to serve in 5G new radio (NR) sub-6 GHz n77/n78/n79 and 5 GHz WLAN with good impedance matching. To increase the isolation between the MIMO antenna elements with low complexity and cost, the antenna elements are orthogonally oriented to each other with distance spacing of $0.3\lambda _{\text {o}}$ between elements, including electromagnetic bandgap (EBG) structure, defected ground structure (DGS), capacitive elements (CE), and neutralization line (NL). The simulation results show that the measured mutual coupling between the array elements is improved from −20 to −45 dB. The envelope correlation coefficient is enhanced. In addition, the diversity gain, mean effective gain, and total active reflection coefficient are improved simultaneously. The suggested structure has been designed on CST Microwave Studio 2019. The antennas’ overall dimensions for all methods are the same as they approach 46 mm $\times46$ mm $\times1.6$ mm. The measured gain of the proposed designs ranges from 6 to 9 dBi, and the radiation efficiency approaches 90%. The antennas are fabricated and tested, where better experimental results are noticed compared to the simulation results. Our antennas are designed over FR-4 substrate with a noticeable cost reduction. Each antenna element has a dimension of 15 mm $\times23$ mm $\times1.6$ mm. An “EL” slot into the radiating element and two identical stubs coupled to the partial ground are used to improve the impedance matching and radiation characteristics across the bands of interest. The isolation decreases by 22 dB using the EBG method, reaching the value of −65 dB. Meanwhile, the isolation decreases by 19 dB using the DGS method, reaching −60 dB. Due to gaps between adjacent unit cells and the capacitance generated from the dielectric gap between the top metallic patch and ground plane, the EBG method gives the best results. However, in the CE method, capacitances resulting from the four transmission lines in the bottom side of the antennas (parasitic elements) decrease the isolation by 15 dB, reaching −40 dB. NL method makes the isolation to reach the value of −55 dB. Accordingly, the proposed antenna arrays support 5G NR sub-6 GHz n77/n78/n79 and 5 GHz WLAN, where n77 (3.3–4.2 GHz), n78 (3.3–3.80 GHz), and n79 (4.4–5.0 GHz) require a wideband coverage that extends from 3.3 GHz to at least 5.0 GHz.

In recent years, with the increase of distributed generation (DG) penetration rate, the economic operation of microgrid (MG) has been fully developed, but the energy consumption system based on fossil energy has increased the contradiction of the economy, energy and environment. The process of accelerating the development and utilization of renewable energy are a new focus of social concern. This paper first analyzes the basic characteristics and related policies of the distributed power and demand response (DR) in MG, and introduces the evaluation index of the islanded microgrid. Then, established a multi-objective optimization scheduling model considering the operation performance of islanded microgrid. In model, considered the generation cost of microsources, environmental management cost and power supply reliability of MG, and selected different scene analysis and verification. Used the improved particle swarm optimization-exterior point method (IPSO-EPM) to solve the problem. When the constraint condition is included in the objective function, the problem of falling into the local extremum during planning is avoided as much as possible. Finally, an islanded microgrid is taken as an example to verify the rationality of the proposed model and the effectiveness of the algorithm.

Virtual power plant (VPP) interconnects distributed generation (DG) units, microgrids, and energy storage systems (ESSs) of an electrical power system. This article presents a linear programming cost minimization model of VPP for the design and commitments of DG, ESS, and microgrid. Using a set of renewable energy resources, the proposed model creates a reliable, cost-effective, and environmentally friendly distribution system. Accurately, it illustrates the schedule of the VPP to operate autonomously. The proposed model is applied to a set of United States commercial load profiles to determine the investment benefit of implementing DGs in the power system. Analysis of results concerning variation in energy price illustrates feasible solutions. VPP decision-makers can select the best reasonable solution based on their specific project budget for feature electricity generation. Moreover, results show the need for the proposed method in VPP decision making.