نتایج جستجو برای: islanding detection
تعداد نتایج: 566438 فیلتر نتایج به سال:
In this paper, at first, the non-detection zones (NDZ) of under/over voltage relay have been determined for constant current inverter based DG and then, an islanding detection method is presented using this relay. In the presented method, the DG direct current reference has a fixed value in normal condition, if the point of common coupling (PCC) voltage changes, Idref is determined as a linear ...
Existing control techniques for DG systems are designed to operate a system either in the connected or disconnected (islanding) mode to the utility; thus not allowing for both modes to be implemented and transitioned between. Existing detection and re-closure algorithms can also be improved upon. Dependent upon the method implemented, detection algorithms can either cause distortions in the out...
The connection of inverters for distributed generation photovoltaic systems to the distribution network creates situations of risk to the loads that are connected to the point of common coupling (PCC) and personals who maintain the power grid. A risk that should be avoided is the supply of electricity, by one or more inverters, to the distribution network after disconnecting the main power grid...
This paper presents a pattern recognition-based scheme for detection of islanding conditions in synchronous- based distributed generation (DG) systems. The main idea behind the proposed scheme is the use of spatial features of system parameters such as the frequency, magnitude of positive sequence voltage, etc. In this study, the system parameters sampled at the point of common coupling (PCC) w...
The islanding methods are classified in terms of the islanding principle and the distributed Generation (DG). Islanding detection techniques are mainly divided into three types for distribution systems: Remote, local and communication based techniques. Passive methods are based on the information available on the DG site at the point of common coupling (PCC) with the utility grid. A new approac...
In recent years, based on the growing importance of clean energy in comparison with conventional energy production from fossil fuels, DG systems are gradually becoming more popular all over the world. These resources solve many problem of system. However, these resources create some other problems too. One of the most problem of DGs is unwanted islanding. This paper addresses reliable passive i...
This study proposes a new islanding detection method for use of grid-interconnected distributed generators (DG). The method is based on two indices: the rate of change of frequency (ROCOF) and the rate of change of voltage (ROCOV). When a DG is grid-interconnected, the ROCOF and ROCOV are lower than the threshold value. In contrast, as an islanding occurs, the ROCOF or ROCOV become much higher ...
Integration of distributed generations (DGs) in power grids is expected to play an essential role in the infrastructure and market of electrical power systems. Microgrids are small energy systems, capable of balancing captive supply and requesting resources to retain stable service within a specific boundary. Microgrids can operate in grid-connected or islanding modes. Effective islanding detec...
The high penetration level of distributed generation (DG) provides numerous potential environmental benefits, such as high reliability, efficiency, and low carbon emissions. However, the effective detection of islanding and rapid DG disconnection is essential to avoid safety problems and equipment damage caused by the island mode operations of DGs. The common islanding protection technology is ...
Islanding is a condition where a part of the distribution system becomes electrically isolated from the remainder of the power system. The islanding detection for distributed generation (DG) units becomes an important issue in power system where the DG installations must be managed and protected during the islanded mode of operation. This paper proposed a new signal processing technique by intr...
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