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Pullman, WA, United States

Schweitzer Engineering Laboratories, Inc. designs, manufactures, and supports products and services ranging from generator and transmission protection to distribution automation and control systems. Founded in 1982 by Edmund O. Schweitzer III, SEL shipped the world's first digital protective relay. Presently, the company designs and manufactures embedded system products for protecting, monitoring, control, and metering of electric power systems. E. O. Schweitzer Manufacturing, a manufacturer of fault indicators and sensors started by Edmund O. Schweitzer, Jr. in 1949, became a division of SEL in 2005. Wikipedia.


Minteer T.,Schweitzer Engineering Laboratories
IEEE Transactions on Dielectrics and Electrical Insulation | Year: 2014

Maxwell's stress equation for electrostatics identifies a tensile stress in the direction of the electric field and a pressure normal to this direction. For an isolated, spherically symmetric static charge distribution, Maxwell's stress equation is manipulated using a variant of Stokes' Theorem. The recast stress equation eliminates the stress normal to the electric field and establishes a stress only aligned with the electric field. For two separated, spherically symmetric static charge distributions, Maxwell's stress equation is also manipulated using a variant of Stokes' Theorem. The recast stress equation develops a line stress that only exists on the straight path between the two charge distributions. The analysis and manipulation of Maxwell's stress equation provides some insight into electrostatic stresses and establishes additional tools for the electrical engineer when analyzing electrostatic system stresses. © 2014 IEEE.


Patent
Schweitzer Engineering Laboratories | Date: 2015-05-07

An method for automatically testing an arc flash detection system by periodically or continually transmitting electro-optical (EO) radiation through one or more transmission cables electro-optically coupled to respective EO radiation collectors. A test EO signal may pass through the EO radiation collector to be received by an EO sensor. An attenuation of the EO signal may be determined by comparing the intensity of the transmitted EO signal to an intensity of the received EO signal. A self-test failure may be detected if the attenuation exceeds a threshold. EO signals may be transmitted according to a particular pattern (e.g., a coded signal) to allow an arc flash detection system to distinguish the test EO radiation from EO radiation indicative of an arc flash event.


Patent
Schweitzer Engineering Laboratories | Date: 2014-04-29

A system for resiliently monitoring an electric power delivery system may include a plurality of server intelligent electronic devices (IEDs) configured to monitor and/or control the electric power delivery system. Each server IED may be communicatively coupled to a client control system by a plurality of communication paths. If a communication path fails, communication may continue along another path. In an embodiment, the client control system may include dual primary client controllers that continually request information from the server IEDs using multiple of the communication paths. The client controllers may request information from each other if the information is not received from the server IEDs, for example, due to a communication failure. In an embodiment, the client control system and server IEDs may be communicatively coupled in a loop topology, and each direction around the loop may be a distinct communication path.


The present disclosure pertains to systems and methods for detecting faults in an electric power delivery system. In one embodiment, a system may include a data acquisition subsystem configured to receive a plurality of representations of electrical conditions. The system may also include a traveling wave differential subsystem configured to determine an operating quantity based on the plurality of representations of electrical conditions. The traveling wave differential subsystem may also determine a restraint quantity based on the plurality of representations of electrical conditions. The traveling wave differential subsystem may detect a traveling wave generated by the fault based on the plurality of representations. A fault detector subsystem may be configured to declare a fault based on a comparison of the operating quantity and the restraint quantity. A protective action subsystem may implement a protective action based on the declaration of the fault.


The present disclosure pertains to systems and methods for detecting faults in an electric power delivery system. In one embodiment, system may include a data acquisition subsystem configured to receive a plurality of representations of electrical conditions. The system may also include an incremental quantities subsystem configured to calculate an incremental current quantity and an incremental voltage quantity based on the plurality of representations. A fault detection subsystem may be configured to determine a fault type based on the incremental current quantity and the incremental voltage quantity, to select an applicable loop quantity, and to declare a fault based on the applicable loop quantity, the incremental voltage quantity, and the incremental current quantity. A protective action subsystem may implement a protective action based on the declaration of the fault.

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