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Our industry moves energy at the speed of light, at the flick of a switch. A transmission line transporting 1500 megawatts delivers the equivalent of 250 pounds of coal per second, already converted into a convenient form of energy. For decades, we considered time in seconds or cycles: such as fuse curves and breaker clearing times. About three decades ago, our thinking moved into milliseconds because...
Today's relays are predominantly based on phasors, and as such, they incur a delay associated with the full-cycle observation window required for accurate phasor estimation. Considerable improvement in speed is possible by using information in the transients of voltages and currents. We review a number of protection techniques, including directional elements, direct tripping underreaching elements,...
Faults on overhead transmission lines cause transients that travel at the speed of light and propagate along the power line as traveling waves (TWs). This paper provides an overview of TWs and TW fault locators. It explains the physics, reviews the theory of TWs, explains the foundations of various types of TW fault locators, and provides an in-depth discussion on a number of TW fault locating implementation...
The IEEE PSRC System Protection Subcommittee Working Group C14 has produced a report that describes practical applications of synchrophasors in protection applications. The report begins with the history of synchrophasors and then goes into issues to consider in their application. Some existing applications are described and then future applications that have been considered or are in development...
Traditionally, microprocessor-based relays incorporate a secondary current transformer to convert the 5 A or 1 A input current to a lower level for input to an analog-to-digital (A/D) converter as part of the input processing. The limits of this input circuit are well known, and relay designers take them into account when determining operating characteristics. A Rogowski coil produces an output based...
Ethernet-based local area networks (LANs) have become an indispensable tool that promises to revolutionize power system communications. Recent advances in Ethernet-based technology have taken this industry from shared 10 Mbps LAN segments to switched 100 Mbps LANs followed by 1 Gbps backbones for metropolitan area networks (MANs) and more recently 10 Gbps Ethernet technology for use in wide-area networks...
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