1,721,080 research outputs found
A diagnostic method for microgrids and distributed generation based on the parameter state estimate
No full textSelective overcurrent protection for large MV installations
No full textThe coordination of protection systems may prove very difficult at large installations, especially
when many circuits are present and several hierarchical levels must be satisfied, involving both protection
devices and automatic control systems. In this context, protection selectivity plays an important role as
concerns the continuity level of power supply and the general power quality of the whole electrical system.
The issue was investigated at an important underground laboratory of the Italian National Institute for Nuclear
Physics (INFN). A preliminary analysis was performed paying special attention to the phenomenon of inrush
currents, which was investigated also through laboratory tests consisting of a sequence of energizations of a
power transformer. In order to replicate the behavior of a large installation, a digital simulator was
implemented. Moreover, in this paper a case study is reported where this same simulator was used to analyze a
portion of the plant under investigation, assuming as reference a number of significant scenarios involving
both normal operating conditions and fault contingencies. The results of the experimental tests, the simulation
analysis and possible strategies for a selective protection plan are finally examined and compared, with an aim
to supply suggestions to correctly protect very large, sensitive electrical installations
Analisi del guasto a terra in reti MT a neutro isolato esercite a due livelli di tensione
No full textComputer relaying for smart grid protection
No full textIn order to improve reliability and availability in upcoming smart grids, a number of effective
actions based on new digital protection systems are suggested. The functions of new generation digital
protections are presented and discussed, and operating solutions in designing smart grid protection plans are
illustrated. As a matter of fact, smart grids are crucial, complex systems that must ensure a very high quality
of the electric power delivered. In order to increase the distribution system reliability, also protection backup
systems are identified and discussed. The main digital functions investigated are overcurrent code,
directional overcurrent code and undervoltage code. Considerations on the selectivity plan and apparatus
setting are also made. Finally, comments and suggestions are reported about the reconfiguration and
restoration of the power system after a fault clearance
SmartGrids and distributed generation: the future electricity networks of the European Union
No full text
A filtering procedure based on least squares and Kalman algorithm for parameter estimate in distance protection
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