Introduction Of Distributed Generation Research Articles

Protective Relaying Coordination in Power Systems Comprising Renewable Sources: Challenges and Future Insights

This article provides a comprehensive review of optimal relay coordination (ORC) in distribution networks (DNs) that include distributed generators (DGs). The integration of DGs into DNs has become a real challenge for power system protection, as the power flow changes from unidirectional to bidirectional, which complicates the relay settings. The introduction of DGs in DNs requires changes and modifications in the protective schemes to maintain proper operation, reliability, stability, and security of the system. This paper focuses on the impacts of DGs penetration into DNs, including the effects on protective scheme coordination. Various expressions for characterizing the overcurrent (OC) coordination problem, as well as related solution attempts, are discussed. Several optimization strategies and techniques are suggested by scientists to deal with coordination optimization problems aiming to achieve less computation time and better accuracy. All these efforts ultimately aim to define optimal relay settings to achieve ORC by generating the optimal setting of cascading relative OC relays. This comprehensive review provides a broad overview of the contributions of scholars in recent publications in this field, with more than 210 articles reviewed and analyzed. It is a valuable resource for other researchers in the same field who aim to tackle ORC problems in their future endeavors.

Optimal Multi-Objective Placement and Sizing of Distributed Generation in Distribution System: A Comprehensive Review

For over a decade, distributed generations (DGs) have sufficiently convinced the researchers that they are the economic and environment-friendly solution that can be integrated with the centralized generations. The optimal planning of distributed generations requires the appropriate location and sizing and their corresponding control with various power network types to obtain the best of the technical, economical, commercial, and regulatory objectives. Most of these objectives are conflicting in nature and require multi-objective solutions. Therefore, this paper brings a comprehensive literature review and a critical analysis of the state of the art of the optimal multi-objective planning of DG installation in the power network with different objective functions and their constraints. The paper considers the adoption of optimization techniques for distributed generation planning in radial distribution systems from different power system performance viewpoints; it considers the use of different DG types, distribution models, DG variables, and mathematical formulations; and it considers the participation of different countries in the stated DG placement and sizing problem. Moreover, the summary of the literature review and critical analysis of this article helps the researchers and engineers to explore the research gap and to find the future recommendations for the robust optimal planning of the DGs working with various objectives and algorithms. The paper considers the adoption of uncertainties on the load and generation side, the introduction of DGs with energy storage backups, and the testing of DG placement and sizing on large and complex distribution networks.

A Comprehensive Review of Protection Schemes for Distributed Generation

Due to the increasing demand of energy and the need for nonconventional energy sources, distributed generation (DG) has come into play. The trend of unidirectional power flow has been gradually shifting. With new technology comes new challenges, the introduction of DG into the conventional power system brings various challenges; one of the major challenges is system protection under DG sources. These sources pose a significant challenge due to bidirectional flows from DGs as well as lower fault current contribution from inverter interfaced DGs. This paper reviews existing protection schemes that have been suggested for active distribution networks. Most of these protection strategies apply only to smaller distribution systems implying that they may need to be extended to larger systems with a much higher penetration of distributed generation. In the end, a potential protection scheme has also been recommended as a future work.

Study on Optimal Mode of Distributed Generation Accessing to Distribution Network

The distributed generation(DG) location, capacity and its influence to distribution network is an important research subject of smart grid. According to the typical daily load curve change rule in distribution network, selecting two operation modes of weighted largest load and weighted least load, taking the minimum of reverse flow times and network loss for the target, combined with the type of DG and operation characteristics , confirming optimal accessing points and optimal capacity of DG. Through the comparative study, the rational introduction of DG improves the voltage level of distribution network and reduces the network loss.

Dynamic Voltage Restorer Cost Reduction in the Distributed Generation Environment

The deregulation trend stimulates engineers to reconfigure the electric system's structure and to establish new concepts for coordination among existing and new electric equipment. Recently, distributed generation (DG) has been introduced as a local power source for both electric utilities and customers. This article presents the positive and revolutionary impact of the existing DG in assisting the dynamic voltage restorer (DVR) in mitigating severe transient problems such as different types of voltage sags. It also consummates the union of two power devices, the DG and DVR, which have never interacted together in a power system before. With the introduction of DG into the system, the DVR's rating and cost are reduced. Digital simulation results are demonstrated to show the substantial impact of DG in stabilizing the system voltage profile and reducing the DVR rating. A brief cost analysis is introduced to emphasize the constructive impact of DG in reducing the DVR costs.