In recent years, the subject of wide-area synchronized measurements has gained a significant amount of attention from the power system researchers. All of this started with the introduction of the Phasor Measurement Unit (PMU), which added a new perspective in the field of wide-area measurement systems (WAMS). With the ever evolving technologies over the years and the need for a more cost effective solution for synchronized frequency measurements, the Frequency Monitoring Network (FNET) was developed and introduced by the Power IT laboratory at Virginia Tech. The FNET is comprised of many Frequency Disturbance Recorders (FDR) geographically distributed throughout the United States. The FDR is a dedicated data acquisition device deployed at the distribution level, which allows for a lower cost and easily deployable WAMS solution. With Internet connectivity and GPS timing synchronization, the FDR provides high accuracy frequency, voltage magnitude and voltage angle data to the remote servers. Although the current FDR design is up to the standard in terms of the measurement accuracy and portability, it is of interest to further the research into alternative architectures and leverage the ever advancing technologies in high speed computing. One of the purposes of this dissertation is to present novel design options for a new generation of FDR hardware design. These design options will allow for more flexibility and to lower reliance on some vendor specific components. More importantly, the designs seek to allow for more computation processing capabilities so that more accurate frequency and angle measurements may be obtained. Besides the fact that the accuracy of frequency and angle measurement is highly dependent on the hardware and the algorithm, much can be said about the role of timing synchronization and its effects on accurate measurements. Most importantly, the accuracy of the frequency and angle estimation is highly dependent on the sampling time of local voltage angles. The challenges to accurate synchronized sampling are two folds. One challenge has to do with the inherent fallbacks of the GPS receiver, which is relatively high cost and limited in availability when the satellite signal is degraded. The other challenge is related to the timing inaccuracies of the sampling pulses, which is attributed to the remainder that results from the imperfect division of the processor counter. This dissertation addresses these issues by introducing the implementation of the high sensitivity (indoor) GPS and network timing synchronization, which aims to increase the availability of frequency measurements in locations that would not have been possible before. Furthermore, a high accuracy timing measurement system is introduced to characterize the accuracy and stability of the conventional crystal oscillator. To this end, a new method is introduced in close association with some prior work in generating accurate sampling time for FDR. Finally, a new method is introduced for modeling the FDR based on the sampling time measurements and some results are presented in order to motivate for more research in this area. / Ph. D.

This dissertation studied new transmission line fault diagnosis approaches using new technologies and proposed a scheme to apply those techniques in preventing and mitigating cascading blackouts. The new fault diagnosis approaches are based on two time-domain techniques: neural network based, and synchronized sampling based. For a neural network based fault diagnosis approach, a specially designed fuzzy Adaptive Resonance Theory (ART) neural network algorithm was used. Several ap- plication issues were solved by coordinating multiple neural networks and improving the feature extraction method. A new boundary protection scheme was designed by using a wavelet transform and fuzzy ART neural network. By extracting the fault gen- erated high frequency signal, the new scheme can solve the difficulty of the traditional method to differentiate the internal faults from the external using one end transmis- sion line data only. The fault diagnosis based on synchronized sampling utilizes the Global Positioning System of satellites to synchronize data samples from the two ends of the transmission line. The effort has been made to extend the fault location scheme to a complete fault detection, classification and location scheme. Without an extra data requirement, the new approach enhances the functions of fault diagnosis and improves the performance. Two fault diagnosis techniques using neural network and synchronized sampling are combined as an integrated real time fault analysis tool to be used as a reference of traditional protective relay. They work with an event analysis tool based on event tree analysis (ETA) in a proposed local relay monitoring tool. An interactive monitoring and control scheme for preventing and mitigating cascading blackouts is proposed. The local relay monitoring tool was coordinated with the system-wide monitoring and control tool to enable a better understanding of the system disturbances. Case studies were presented to demonstrate the proposed scheme. An improved simulation software using MATLAB and EMTP/ATP was devel- oped to study the proposed fault diagnosis techniques. Comprehensive performance studies were implemented and the test results validated the enhanced performance of the proposed approaches over the traditional fault diagnosis performed by the transmission line distance relay.