Abstract-Optimum Distributed Generation (DG) placement and sizing is one of the current topics in new restructured power system. Most of the authors have worked out either DG unit placement or shunt capacitor placement as criteria for minimization of power system losses. However in the present paper, both approaches have been combined together to achieve overall minimum power losses and better voltage regulation. Particle Swarm Optimization (PSO) algorithm will be used for simultaneous finding of optimum DG and shunt capacitor bank location and size. The proposed algorithm will be tested on 12-bus, 30-bus, 33-bus and 69-bus radial distribution networks and the results will also be discussed in detail.Index Terms-DG unit placement, shunt capacitor, particle swarm optimization (PSO), distribution system, power losses.

An electrical power system is considered as a critical infrastructure (CI), the epicenter of a nation's economy, security, and health. It is interlinked with other CIs such as gas and water supplies and transportation and communication systems. A failure in the power system will immensely affect the functionality of these CIs. Therefore, enhancing power system resilience is crucially needed to ensure continuous operation of these CIs. One of the possible approaches to improve the resilience in a power system is by integrating microgrids in the power system. Microgrids have proven to have self-healing and resilient capabilities in such extreme events which inflict damage out of the conventional scope of failures. Operational flexibility and controllability make microgrids a viable solution for resilience enhancement. This paper reviews the concept of resilience in power systems and the functions of microgrids in enhancement of resilience. The most current studies in improving power system resilience through microgrids are reviewed by highlighting their advantages and limitations.

Technology advancement in the last few decades allows large penetration of renewable energy resources in the distribution network (DN). The integration of such resources has shown a substantial impact on DN through power loss reduction and improved network reliability. Besides this, the existing protection system has encountered coordination challenges due to the bidirectional power flow, different types and capacity of generation sources, and changes in fault levels due to network operating modes (grid-connected or islanded). Such conditions may cause the relays to malfunction and imperil the effectiveness of the existing protection scheme. Therefore, an efficient and robust protection coordination scheme is imperative to avoid network reliability and stability issues to the grid. This review paper presents a comparative analysis of various protection techniques implemented to alleviate the impact of integrated resources into DN. Moreover, a comparison of classical and modified protection approaches in terms of advantages, shortcomings, and implementation costs is presented. The prime objective of this study is to highlight the prominence of utilizing user-defined programmable relays for modern DNs. Moreover, recommendations are presented by considering the application of user-defined relay characteristics that can be proved as a robust protection scheme to cope with the protection challenges in existing and future power systems developments.INDEX TERMS Distribution networks (DN), microgrids (MG), protection coordination scheme, renewable energy resources (RES), user-defined characteristics (UDC).

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