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The goal of this paper is to design a protection system capable of detecting, isolating and locating high and low impedance ground faults in a DC multi-terminal system using a Digital Signal Processing (DSP) based control unit. Due to low current fluctuations during faults, it becomes difficult to detect high impedance faults using conventional methods. In order to locate faults, the DC ring bus will be divided into different zones and an algorithm will be developed to monitor currents in each zone. The proposed method has been tested through examples and is seen to be cost effective and easy to implement.Index Terms-DC microgrid, Ground fault impedance.

Solar power received on the surface of any object on the earth could be considered as the power absorbed in the entire volume of that object and hence measured in Watts per unit volume. In this paper, effectiveness of measuring power and energy per unit volume and the impact of height in system efficiency is analyzed. Variations in solar radiation intensity based on the angles of the Sun during the day and the year is briefly reviewed.It is shown how the wide ranges of these variations can affect efficiency of a solar power generating system and its energy delivery. Module of Irradiance and Collectivity Factors are introduced as parameters to estimate power/energy entering a volume and the efficiency of the system. Cost efficiency of the system is discussed considering all high cost items such as land, collector equipment and the supporting structure. A solar powertracking concept is analyzed and shown how it would significantly increase the efficiency of the system. Feasibility of tracker in solar power generation is studied based on Tracking factor as defined here.

Application of Distributed Generation (DG) to supply the demand of a diverse customer base has been gaining popularity. Various DG technologies are being integrated into power systems to provide alternatives to energy sources or to improve reliability. In this paper, the effects of DG on system protection have been identified. Changes in system fault duties and associated concerns are presented. Commonly raised issues of Relay De-sensitization, UnintentionalIslanding, Series Resonance, and Ferroresonance are identified, and some methods of their detection are discussed and analyzed. Documented examples of actual cases are presented. Efficient recommendations to protect the distribution feeders against these conditions are proposed.

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