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The last years in Europe, the growing penetration of Distributed Generation (DG), (mainly q combination of heat and power (CHP) and renewable), has demonstrated the necessity of facing the impacts and opportunities of new distributed energy resources connected to medium and low voltage grids by means of research projects. The need of demonstration projects on voltage control with DG to increase the...
Microgrids are key elements to integrate renewable and distributed energy resources as well as distributed energy storage systems. In the last years, efforts toward the standardization of these microgrids have been made. In this sense, this paper presents the hierarchical control which consist of three levels: i) the primary control is based on the droop method, including an output impedance virtual...
The emergence of large amounts of distributed energy resources (DER) poses new challenges for the active participation of those units in the control of the grid. In this context, a recent development is the microgrid, which presents a coordinated approach for integrating the DER in the electrical grid. Microgrids are able to operate either connected to the distribution grid or in islanded mode. In...
With more and more distributed energy resources (DERs) being connected to the grid through interface converters, the utility requires the DER generation system to remain grid-connected during voltage sags to ensure the operating stability of the AC power system. These low voltage ride-through requirements also suggest that the DER generation system injects reactive power to support grid voltages....
In this paper, the field tests conducted by the IITREE-LAT to verify the performance of motor-generators are presented. These machines are used as distributed energy resources (DER) in oil fields and different cities across Argentina. On the basis of these tests, the models regarding generator, power-speed control system and voltage control system are presented.
Distributed energy resources such as photovoltaic, fuel cells and micro turbines are emerging into power supply systems. Strategies of grid control integration, to emerge these sources are still lagging behind. These sources require interfacing units to provide the necessary crossing point to the grid. The cores of these interfacing units are power electronics technologies such as inverters (multifunctional...
This paper presents a novel wireless load-sharing control strategy, active droop positioning, for islanding parallel inverters in an ac-distributed system. Normally, the microgrid is intended to operate in islanded mode when the disconnection from the upstream MV network occurs. In this condition, the inverter-interfaced microsources acts as a voltage source, with the magnitude and frequency of the...
Distributed energy resources are increasingly being connected to the utility grid by means of an inverter. The basic information necessary for these inverter-connected distribution units are the frequency and phase angle of the utility grid. The phase angle can be estimated using phase-locked loops (PLLs). Voltage unbalance, harmonics and other kinds of undesirable pertubations are common conditions...
This paper presents optimal design of controllers of the general type of proportional-integrating-derivative (PID) for achieving optimal tracking of a constant or slow-changing set-point. The design method is developed for the first- and second-order plants (with or without zero) in which only an output signal is used for the feedback. A generalization of the proposed method for higher-order plants...
Distributed energy resources (DE) with power electronics (PE) interfaces with the right control are capable of providing reactive power related ancillary services. Voltage regulation in particular has drawn much attention. In this paper the challenges to control multiple DEs to regulate the local voltage in distribution systems is addressed and a decentralized adaptive voltage control method is proposed...
The integration of distributed energy resources (DES) with the distribution network offers a number of technical, environmental, and economical benefits. This paper demonstrates the functions of a series grid interconnection module that integrates distributed generations (DG) and energy storage (ES) for peak load shaving and power quality enhancement. The proposed module uses a voltage source converter...
Efficient and effective use of renewable energy, distributed generation and energy storage can potentially solve global problems such as energy crisis and climate change. A promising solution to interconnecting these distributed energy resources with the grid is the microgrid paradigm. A microgrid may comprise a variety of inverter-interfaced distributed energy resources such as photovoltaic arrays,...
New grid codes requires distributed energy resources to ride through temporary low voltage event and at the same time injecting reactive current into the grid. In microturbine generation system (MTGS) connected to the grid through power electronic converter, during low voltage ride through, its DC-link voltage increases and MTGS converter is overloaded. The paper discussed and highlights the problems...
One solution for increasing the use of renewables is to find new strategies to allow distributed energy resources (DER) connection with the existing power system. A solution which allows a flexible integration of dispersed generation (DG) into energy networks is the use of DC at the user layer. One reason for choosing nowadays the DC technology for electrical energy distribution is the trend in the...
Due to the rapid increase in global energy consumption and the diminishing of fossil fuels, the customer demand for new generation capacities and efficient energy production, delivery and utilization keeps rising. Utilizing distributed generation, renewable energy and energy storage can potentially solve such problems as energy shortage and global warming. A promising structure to interconnect these...
This paper presents a microgrid paradigm with both DC and AC links, which may provide an effective way to integrate a heterogeneous set of small-size distributed energy resources into the existing electric power infrastructure. The collection of aggregated energy resource units at each level represents those distributed resources to the upper level as a single self-regulated entity (as a DC or AC,...
Distributed energy resources (DE) have been widely used in the power systems to supply active power, and most of the present DE resources are operated with limited or without nonactive power capability. This paper shows that with a slight modification in hardware configuration and a small boost in the power ratings, as well as proper implementation of control strategies, a DE system with a power electronics...
The many different islanding detection methods for anti-islanding protection in power system are discussed. Passive, active and remote techniques are reviewed. Most of the ldquoactive methodsrdquo discussed are developed for photovoltaic (PV) as a distributed energy resource. Some recent methods can be use for any type of distributed generation. A final comparison of active islanding detection methods...
This paper proposes a detailed mathematical model and a multi-level control scheme of a three-phase grid-connected photovoltaic (PV) system used as a dispersed generator, including the PV array and the electronic power conditioning (PCS) system, based on the Matlab/Simulink software. The model of the PV array proposed uses theoretical and empirical equations together with data provided by the manufacturer,...
This paper describes an approach to hierarchical integration of DC and AC microgrids containing distributed energy resources (DERs) into the existing electric power distribution infrastructure. Power electronic interfaces and controls permit the aggregated units at each level to represent themselves to a higher level as a single self-controlled entity (DC or AC, load or generator). At the top level...
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