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1. A New Harmonic-based Protection structure for Meshed Microgrids

   https://doi.org/10.1109/PESGM.2018.8585807  

   Beheshtaein, Siavash; Cuzner, Rob; Savaghebi, Mehdi; Guerrero, Josep M. (August 2018, 2018 IEEE Power & Energy Society General Meeting (PESGM))

   This paper presents a novel harmonic-based overcurrent relay which detects and isolates three-phase faults in a meshed microgrid. The harmonic signals are generated by two Distributed Generators (DGs) which each of them communicate with its adjacent DG. In the first step, a set of features are extracted from DG output signal and then fed to a Support Vector Machine (SVM) to detect occurrence of fault. Once the fault is detected, based on minimum voltage measured by DG, two closest DGs will recognize and these two DGs inject two distinct harmonics to activate harmonic-based relays. As each set of relays located at either beginning or end of each section is activated by current with specific frequency, these relays behave like directional relays without using voltage transformers. As a result, the proposed method is cost-effective solution. The optimum Time Dial Settings (TDSs) of these relays are obtained by solving a coordination problem with Particle Swarm Optimization (PSO) algorithm. Real-time results are taken by OPAL-RT to show the effectiveness of the proposed method for two different locations of fault in a meshed microgrid. 

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2. Fault location in microgrids: a communication‐based high‐frequency impedance approach

   https://doi.org/10.1049/iet-gtd.2018.5166  

   Beheshtaein, Siavash; Cuzner, Robert; Savaghebi, Mehdi; Golestan, Saeed; Guerrero, Josep_M (February 2019, IET Generation, Transmission & Distribution)

   This paper proposes a novel method to locate faults in an AC‐meshed microgrid. To this end, a set of features is first extracted and selected from the measured signals and fed to a Support Vector Machine (SVM) to detect the occurrence of fault. Then, the Distributed Generator (DG) with the lowest amount of fundamental voltage, which is the closest one to the fault, injects an appropriate voltage/current harmonic. As the faulted section has the lowest impedance value from the Point of Common Coupling of the DG, the harmonic current of the corresponding line has the highest value. Based on this fact, the first candidate DG sends a notification signal to the second candidate DG, in which the fault occurs between them. Finally, the impedances in the injected frequency are measured from these two DGs and fed into a multi‐class SVM to locate the faulted line. The proposed method has the ability to locate faults for islanded and grid‐connected microgrids with variable configurations. Real‐time simulation results are taken by OPAL‐RT to show the effectiveness of the proposed method in the meshed microgrid. 

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3. Coordination of Protection and Ride-through Settings for Islanded Facility Microgrids

   https://doi.org/10.1109/ECCE47101.2021.9595450  

   Vygoder, Mark; Banihashemi, Farzad; Gudex, Jacob; Cuzner, Robert M; Oriti, Giovanna (October 2021, 2021 IEEE Energy Conversion Congress and Exposition (ECCE))

   Proliferation of power electronics and distributed energy resources (DERs) into the electrical power system (EPS) enables improvements to the network’s resilience against sudden-inception short circuit electrical faults through redundant electrical pathways in meshed configurations and multiple possible distributed generation locations. However, successful operation of fault detection, isolation, and recovery in islanded mode is challenging as protection coordination must include not only the distribution equipment, but also the DERs. Assessment of resilience for candidate EPS architectures against short circuit faults must be performed to understand the trade-offs between network resilience and complexity. This paper proposes a design process, which can be used towards assessing microgrid resilience, by coordinating protection and ride-through settings to maximize the recoverability of a meshed islanded AC microgrid. The design process is demonstrated through a case-study. 

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4. Protecting Inverter-Based Resources: Transformer Configuration Impacts and Incremental Focused Directional Protection Enhancements

   Hasan, Abu_Shouaib; Fan, Rui (March 2025, IEEE GreenTech Conference)

   Inverter-based resources (IBRs) exhibit distinct short-circuit characteristics that challenge traditional protective relays designed for systems dominated by synchronous generators. While research often focuses on IBRs’ positive-sequence currents during faults, their zero- and negative-sequence responses under unsymmetrical faults remain underexplored. Factors such as transformer configurations and grounding methods further complicate the design of protection schemes relying on these sequence components. This paper enhances the understanding of IBR short-circuit behavior during both symmetrical and unsymmetrical faults and investigates the impact of various transformer configurations on these behaviors. We highlight the limitations of traditional protective relays in safeguarding IBRs due to their constrained fault current levels, minimal negative-sequence components, and, in many cases, the absence of zero-sequence currents. To address these challenges, a novel incremental focused directional protection scheme is introduced. This approach offers enhanced fault detection capabilities under the complex conditions posed by high renewable energy penetration and diverse transformer configurations. The proposed method provides a robust solution for ensuring reliable protection in modern power systems with high integration of IBRs, contributing to improved grid stability and resilience. 

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5. Solar energy management as an Internet of Things (IoT) application

   https://doi.org/10.1109/IISA.2017.8316460  

   Spanias, Andreas S. (August 2017, 2017 IEEE 8th International Conference on Information, Intelligence, Systems & Applications (IISA))

   Photovoltaic (PV) array analytics and control have become necessary for remote solar farms and for intelligent fault detection and power optimization. The management of a PV array requires auxiliary electronics that are attached to each solar panel. A collaborative industry-university-government project was established to create a smart monitoring device (SMD) and establish associated algorithms and software for fault detection and solar array management. First generation smart monitoring devices (SMDs) were built in Japan. At the same time, Arizona State University initiated research in algorithms and software to monitor and control individual solar panels. Second generation SMDs were developed later and included sensors for monitoring voltage, current, temperature, and irradiance at each individual panel. The latest SMDs include a radio and relays which allow modifying solar array connection topologies. With each panel equipped with such a sophisticated SMD, solar panels in a PV array behave essentially as nodes in an Internet of Things (IoT) type of topology. This solar energy IoT system is currently programmable and can: a) provide mobile analytics, b) enable solar farm control, c) detect and remedy faults, d) optimize power under different shading conditions, and e) reduce inverter transients. A series of federal and industry grants sponsored research on statistical signal analysis, communications, and optimization of this system. A Cyber-Physical project, whose aim is to improve solar array efficiency and robustness using new machine learning and imaging methods, was launched recently 

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