George J. Cokkinides

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This paper presents the application of the virtual test bed for visualization and animation of protective relaying problems. The development of protective relaying animation and visualization objects as well as the interfacing with the virtual test bed is described. Two examples of protective relaying animation are presented: (a) modified mho relays and (b)(More)
In a deregulated environment, independent generators and utility generators may or may not participate in the load-frequency control of the system. For the purpose of evaluating the performance of such a system, a flexible method has been developed and implemented. The method assumes that load frequency control is performed by an ISO based on parameters(More)
GPS-synchronized equipment (PMUs) is in general higher precision equipment as compared to typical SCADA systems. Conceptually, PMU data are time tagged with accuracy of better than 1 microsecond and magnitude accuracy that is better than 0.1%. This potential performance is not achieved in an actual field installation due to errors from instrumentation(More)
The objectives of smart grid and grid modernization are to increase automation and seamlessly integrate data, models, protection, optimization and control of the power grid. This effort is affected by technological advances. One such technology is the numerical relay which has increased its domination to the point that today has almost completely displaced(More)
A new tool for computing and visualizing the operation of power system components and systems is presented. One component of the tool is a time domain simulator that operates in the background within a multitasking environment. Visualization and animation objects can retrieve data in real time from the time domain simulator and display a detailed picture of(More)
The SuperCalibrator concept was introduced to take advantage of the characteristics of GPS-synchronized equipment (PMUs). Specifically, GPS-synchronized equipment has the capacity to provide precise phase measurements (to 0.01 degrees accuracy) and relatively good quality magnitude measurements (up to 0.1% accuracy). However in a practical environment this(More)
Reliable real time system " visibility " depends on a reliable and accurate state estimator. Present experience with state estimators indicates that its reliability is below expectations (an average of 5% non-convergent cases). The causes of this poor performance have been identified in earlier work by the authors and alternative robust state estimators(More)