بایگانی برچسب برای: distributed generation (DG)

Benefits of Power Electronic Interfaces[taliem.ir]

Benefits of Power Electronic Interfaces for Distributed Energy Systems

With the increasing use of distributed energy (DE) systems in industry and its technological advancement, it is becoming more important to understand the integration of these systems with the electric power systems. New markets and benefits for DE applications include the ability to provide ancillary services, improve energy efficiency, enhance power system reliability, and allow customer choice. Advanced power electronic (PE) interfaces will allow DE systems to provide increased functionality through improved power quality and voltage/volt–ampere reactive (VAR) support, increase electrical system compatibility by reducing the fault contributions, and flexibility in operations with various other DE sources, while reducing overall interconnection costs. This paper will examine the system integration issues associated with DE systems and show the benefits of using PE interfaces for such applications.
Power Management Strategies for a Microgrid With[taliem.ir]

Power Management Strategies for a Microgrid With Multiple Distributed Generation Units

This paper addresses real and reactive power management strategies of electronically interfaced distributed generation (DG) units in the context of a multiple-DG microgrid system. The emphasis is primarily on electronically interfaced DG (EI-DG) units. DG controls and power management strategies are based on locally measured signals without communications. Based on the reactive power controls adopted, three power management strategies are identified and investigated. These strategies are based on 1) voltage- droop characteristic, 2) voltage regulation, and 3) load reactive power compensation. The real power of each DG unit is controlled based on a frequency-droop characteristic and a complimentary frequency restoration strategy. A systematic approach to develop a small-signal dynamic model of a multiple-DG microgrid, including real and reactive power management strategies, is also presented. The microgrid eigen structure, based on the developed model, is used to 1) investigate the microgrid dynamic behavior, 2) select control parameters of DG units, and 3) incorporate power management strategies in the DG controllers. The model is lso used to investigate sensitivity of the design to changes of parameters and operating point and to ptimize performance of the microgrid system. The results are used to discuss applications of the proposed power management strategies under various microgrid operating conditions.
An Accurate Power Control Strategy for[taliem.ir]

An Accurate Power Control Strategy for Power-Electronics-Interfaced Distributed Generation Units Operating in a Low-Voltage Multibus Microgrid

In this paper, a power control strategy is proposed for a low-voltage microgrid, where the mainly resistive line impedance, the unequal impedance among distributed generation (DG) units, and the microgrid load locations make the conventional frequency and voltage droop method unpractical. The proposed power control strategy contains a virtual inductor at the interfacing inverter output and an accurate power control and sharing algorithm with consideration of both impedance voltage drop effect and DG local load effect. Specifically, the virtual inductance can effectively prevent the coupling between the real and reactive powers by introducing a predominantly inductive impedance even in a lowvoltage network with resistive line impedances. On the other hand, based on the predominantly inductive impedance, the proposed accurate reactive power sharing algorithm functions by estimating the impedance voltage drops and significantly improves the reactive power control and sharing accuracy. Finally, considering the different locations of loads in a multibus microgrid, the reactive power control accuracy is further improved by employing an online estimated reactive power offset to compensate the effects of DG local load power demands. The proposed power control strategy has been tested in simulation and experimentally on a low-voltage microgrid prototype.
Application of Duffing Oscillators for[taliem.ir]

Application of Duffing Oscillators for Passive Islanding Detection of Inverter-Based Distributed Generation Units

Regarding the safety and reliable operation of modern distributed generation (DG) systems, an expert diagnosis apparatus is required to distinguish between different events. One of the crucial requirements in DG safe operation is the “islanding detection.” In this paper, a new passive islanding detection method, based on the application of the Duffing oscillators, is suggested for the first time and tested under different network conditions. The method is designed to detect the changes on point of common coupling frequency by identifying the transformation of the Duffing oscillator from “chaotic state” to “great periodic state” and vice-versa. The simulations results, carried out by MATLAB/Simulink, are used to validate the performance of the proposed method. It is shown that the proposed method has excellent accuracy within a minimum detection time, even with the presence of high noise to signal ratios.
Combined Operation of Unified Power-Quality[taliem.ir]

Combined Operation of Unified Power-Quality Conditioner With Distributed Generation

This paper describes analysis results of a combined operation of the unified power quality conditioner with the distributed generation. The proposed system consists of a series inverter, a shunt inverter, and a distributed generator connected in the dc link through rectifier. The proposed system can compensate voltage sag and swell, voltage interruption, harmonics, and reactive power in both interconnected mode and islanding mode. The performance of proposed system was analyzed using simulations with power system computer aided esign/electromagnetic transients dc analysis program, and experimental results with the hardware prototype. The proposed system can improve the power quality at the point of installation on power distribution systems or industrial power systems.
Application of Duffing Oscillators for[taliem.ir]

Application of Duffing Oscillators for Passive Islanding Detection of Inverter-Based Distributed Generation Units

Regarding the safety and reliable operation of modern distributed generation (DG) systems, an expert diagnosis apparatus is required to distinguish between different events. One of the crucial requirements in DG safe operation is the “islanding detection.” In this paper, a new passive islanding detection method, based on the application of the Duffing oscillators, is suggested for the first time and tested under different network conditions. The method is designed to detect the changes on point of common coupling frequency by identifying the transformation of the Duffing oscillator from “chaotic state” to “great periodic state” and vice-versa. The simulations results, carried out by MATLAB/Simulink, are used to validate the performance of the proposed method. It is shown that the proposed method has excellent accuracy within a minimum detection time, even with the presence of high noise to signal ratios.