a b s t r a c tIn this paper, a real-time tool to detect transmission line relay mis-operation is implemented. The tool uses time-synchronized measurements obtained from both ends of the line during disturbances. The proposed fault analysis tool comes into the picture only after the protective device has operated and tripped the line. The proposed methodology is able not only to detect, classify, and locate transmission line faults, but also to accurately confirm whether the line was tripped due to a mis-operation of protective relays. The analysis report includes either detailed description of the fault type and location or detection of relay mis-operation. As such, it can be a source of very useful information to support the system restoration. The focus of the paper is on the implementation requirements that allow practical application of the methodology, which is illustrated using the field data obtained the real power system. Testing and validation is done using the field data recorded by digital fault recorders and protective relays. The test data included several hundreds of event records corresponding to both relay mis-operations and actual faults. The discussion of results addresses various challenges encountered during the implementation and validation of the presented methodology.
A reliable islanding detection method is one of the most important function of a well designed inverter based distributed generation (DG) system. Active islanding detection methods have negligible non-detection zone, but they bring some power quality issues to the network. In this paper an islanding detection method which addresses constant current inverter based DGs is introduced. It has both high power quality and low non-detection zone. The method makes a positive feedback between reference current of the constant current controller and the rms voltage of inverter terminal in a way that it could detect islanding in the proper time, while providing constant current appropriately. The efficiency of the method is proved using simulations based on PSCAD/EMTDC.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.