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Summary The power grid constructed with electric power router (EPR) will have the ability of flexibly controlling the voltage and power flow on each line of the grid, which will be helpful to maximize the integration of the renewable distributed generation to the grid. Most of the current methods for transmitting energy depend on storage unit or large scale calculation, which are relatively difficult. To avoid these disadvantages, this paper proposed a two‐step routing strategy based on the improved shortest path method for DC power grid with EPRs. The improved shortest path method combines Shortest Path Faster Algorithm (SPFA) with depth first search (DFS) algorithm, which could handle the negative weights and the negative cycle issue in the graph of the power flow paths. The increase of the transmission line power loss and the EPR's power loss are taken as the weight for the path search method to evaluate the cost of the path. Applying the proposed method to each power demand and supply finally helps to obtain the current distribution of the whole grid. By analysis of typical scenarios, compared with the power flow distribution of traditional DC power grid, the one produced by the proposed strategy could improve the power transmission capability as well as reduce the maximum voltage drop in the network. Besides, this strategy introduces less power loss, than many other ways do, in power routing. The effectiveness of the rioting strategy is related to the configuration of the network. [ABSTRACT FROM AUTHOR]

Summary: Nowadays, increasing nonlinear loads as well as distributed generation (DG) sources, which are some of these types, not only cause a wide range of voltage fluctuations, but also make it difficult to control the DG sources to produce proper output. Hence, it is necessary to use an approach that evaluates and tracks the voltage fluctuations, and also to have an output with optimal accuracy and smoothness that is suitable for control of DG sources. This paper presents a Teager energy operator (TEO)‐based approach to track and detect the voltage fluctuations in distribution networks in the presence of the inverter‐based DG and nonlinear load that eliminates as much as possible distortion and unwanted signals from the voltage flicker signal. This hybrid algorithm is able to track accurate the amplitude variations of voltage disturbances in industrial systems. To attain this aim, a suitable combination of the TEO and a relevant filter set is adopted. Simulations for a mathematical fluctuation waveform and the grid‐connected inverter‐based DG using the proposed method are conducted and results are compared with each other to evaluate their performance. Simulation results for different voltage fluctuations validate that the new approach is accurate and smooth in tracking the voltage fluctuations. [ABSTRACT FROM AUTHOR]

This paper presents an application of the chaotic artificial bee colony (CABC) algorithm to identify the optimal location and sizing of the distributed generation (DG) units in order to improve the voltage stability margin in the radial distribution system. Artificial bee colony algorithm is an optimization algorithm based on the intelligent foraging behavior of honey bee swarm. To improve the searching ability of an artificial bee colony algorithm, chaos theory is united with artificial bee colony, called the CABC algorithm. The various impact indices are used to evaluate the multi-objective performance index aimed to identify the optimal location and sizing of combined real and reactive power-based DGs on the distribution systems. The presence of DG in the distribution system has been potential to improve voltage stability of the system. The effect of DG on the weakest bus is analyzed by constructing the PV curve. The effectiveness of the proposed method is tested on 38-node and 69-node radial distribution systems. [ABSTRACT FROM AUTHOR]

This paper proposes a new active islanding detection scheme based on the harmonic impedance measured from distorted current and voltage waveforms. Such distortions are due to periodical short-time phase-to-phase short circuits, caused by firing a thyristor placed between two phases at the distributed generator terminals. Distributed generator islanding is identified by analyzing the change of harmonic impedance. The method was validated by simulation and experimental tests. The results show that the method is effective and robust. Moreover, it was observed that the proposed method is hardly impacted by the interaction among different signals, and its influence on power quality is negligible. Copyright © 2016 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Summary: The increase in the levels of penetration of distributed generation (DG) and the introduction of smart grid functionalities like network reconfiguration to the distribution network have made its fault current levels unpredictable and complicated the design of its protection. This paper studies the use of distribution grid code requirements, which regulate the fault response of DGs, to control the fault current levels in the network. The paper proposes an algorithm to follow when choosing the grid code requirements for DG dynamic voltage support that would allow for the continued use of traditional protection setups with sufficient speed and reliability; this would help avoid the need for more complicated schemes that heavily rely on an external communication layer that might negatively impact the reliability of the system. A motivating example is used to show that depending on the network configuration different voltage support requirements might be needed. By studying all possible configurations, a common range of requirements can be identified. The paper also considers changing the requirements progressively, such that requirements set for DGs currently connected can be different than those added in the future. This is demonstrated with a second case study where DGs are added in three phases. The results show that DGs added in later phases would need to be subject to stricter requirements than those connected in the initial phase. [ABSTRACT FROM AUTHOR]

In this paper, a new and efficient hybrid optimization algorithm is proposed for optimal placement and sizing of the distributed generations (DGs). Bus voltage profile improvement, line flow capacity, and active and reactive power loss minimization are considered as multi-objectives to optimize under-distribution load enhancement. The addition of multi-DGs to the distribution system, which is already having DGs, is studied under increased load demand. Renewable energy resources such as wind, solar, fuel cell, and micro turbines are considered in power system modeling for finding the optimal placement and sizing. Current injection-based distribution load is considered in DGs modeling in power systems. Active and reactive losses and voltage profiles are studied for all combinations of DGs. To optimize the objective function, a new optimization technique called shuffled bat algorithm is proposed. The proposed methodology is tested on 38-bus and 69-bus radial distribution systems with 100% and 120% of base load conditions to demonstrate its performance and effectiveness. Results show that the planned methodology is superior to existing strategies in terms of multi-objectives considered. Copyright © 2015 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

SUMMARY This paper proposes a new approach to distribution system named Three-wire Network (3-NET). Considering the integration of different distributed generation (DG) technologies as well as the diversity of loads, the idea of 3-NET is splitting a single power network into three qualitatively different networks: (i) a high quality direct current (DC) network; (ii) a conventional alternating current (AC) network; and (iii) a low quality DC network. By this configuration, the multi-stage conversion of energy from DG sources can be reduced, whereas loads can be supplied with different power quality and reliability levels as desired. In order to evaluate the potential benefits of 3-NET, the operational strategy is formulated in a market model; the reliability performance is investigated using Monte Carlo simulation and quantified in terms of interruption costs. In the case study, the proposed 3-NET is considered for integrating a certain amount of DG into a specific distribution system and then compared with another system approach: hybrid AC-DC microgrid. The simulation shows that although the operation costs can be slightly higher, the 3-NET shows a great improvement in reliability performance in comparison with the hybrid microgrid. Copyright © 2013 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Summary: A new microgrid architecture suitable for rural electrification of remote hamlets is proposed. The proposed architecture utilizes a new system design that caters both energy as well as the water needs of the community. An intuitive Solar Photovoltaic (SPV) arrangement using a changeover switch is introduced to meet both lighting and water pumping requirements. Before implementation, a feasibility study is made for proposed Mid‐way architecture using MATLAB/Simulink and the results are compared with existing architectures. The computed results indicate that the proposed architecture achieves the lowest voltage drop of 1.7 V and an energy loss of 4.2 Wh compared to other architectures. Further, to validate the system effectiveness an economic analysis is also performed in a practical viewpoint. To demonstrate the prophecy of the proposed architecture, the DC microgrid system is practically installed at Gundichattanahalli village, Karnataka. Besides, an efficient energy management system (EMS) on IoT platform for remote monitoring and control is also integrated with Mid‐way architecture. Both simulation and real time system implementation ascertains system suitability for electrification of remote village or hamlets and its sustainable development. [ABSTRACT FROM AUTHOR]

Summary: Determining the penetration level of the distributed generation (DG) is an effective tool to site and size DGs in distribution networks. A multiobjective function of optimizing the DG penetration level, subject to constraints including short circuit capacity, voltage limits, transformer capacity, reverse power flow, and congestion of lines, is introduced to minimize the real and reactive losses and to ensure the voltage stability considering the variations of loads, different locations and power factors of DGs, and statistical nature of DG powers especially renewable energy resources. This optimization is performed based on a combined probabilistic modeling of the chronological behavior of wind speed, solar irradiance, and load with different types. The dynamical behavior of the compensators and on‐load tap changers is modeled by optimization subfunctions. An improved bee algorithm is used through conducting searches in the neighboring areas based on a new nonlinear function for a higher fitness and coherency speed. [ABSTRACT FROM AUTHOR]