Schweitzer Engineering Laboratories, Inc.

An intelligent electronic device (IED) of an electric power distribution system includes processing circuitry and a memory that includes instructions. The instructions, when executed by the processing circuitry, are configured to cause the processing circuitry to transmit a first data frame and a second data frame to a switch of the electric power distribution system, determine whether the switch transmits the first data frame and not the second data frame, and establish a media access control security key agreement (MKA) based on a determination of whether the switch transmits the first frame and not the second data frame.

A method of manufacture includes applying an identification pattern over a printed circuit board (PCB), capturing an image of the identification pattern applied to the PCB, associating the image with an additional identification pattern associated with the PCB, and storing the image and the association between the image and the additional identification pattern in a database.

The present disclosure relates to systems and methods to detect a fault in an electric power system. One embodiment may detect a single phase broken conductor in a multi-phase electric power system. An intelligent electronic device (IED) may receive a plurality of measurements over time of a current through an electrical conductor in the electric power system. Based on the measurements of the current, a fault detection subsystem may determine a zero-sequence current, a negative-sequence current, and a positive-sequence current. The fault detection subsystem may determine a ratio of the zero-sequence current, the negative-sequence current, and the positive-sequence current, and may monitor the ratio over time. The fault detection subsystem may identify the broken conductor condition based on the ratio and a fault detection region. A protective action subsystem may implement a protective action based on identification of the broken conductor condition.

Systems, methods, and devices for protecting against spoofing of Global Navigation Satellite System (GNSS) data are provided. An electronic device may include memory and one or more processors that execute instructions to cause operations to identify potential GNSS spoofing. The operations may include obtaining a first distance between a first GNSS receiver and a second GNSS receiver, obtaining first GNSS data indicating a first range measurement between a first GNSS satellite and the first GNSS receiver, obtaining second GNSS data indicating a second range measurement between the first GNSS satellite and the second GNSS receiver, and calculating a first expected range measurement between the second GNSS receiver and the first GNSS satellite based at least in part on the first distance and the first range measurement. Spoofing may be determined to have occurred based on a comparison between the first expected range measurement and the second range measurement.

A system for detecting single-phase ground faults is presented herein. Single-phase ground faults on ungrounded or high-impedance single-grounded three-wire power systems are determined by filtering the currents and voltages components to remove noise, extracting the pure-fault current components, and computing their magnitude. The faulted feeder is determined as the one with the largest zero-sequence pure-fault current. of each phase, and filtering the pure-fault current components to remove noise. The faulted phase is determined as the phase with the largest pure-fault current magnitude compared with the other two phases. The detection may be qualified using the fault zero-sequence voltage magnitude.

This disclosure pertains to systems and methods to detect network errors in a parallel redundant protocol (PRP) network. A node-level redundancy error subsystem of an intelligent electronic device (IED) maintains records (e.g., counts) of information associated with missing duplicate frames expected from node devices on the PRP network via redundant first and second local area networks (LANs). Non-zero counts of missing duplicate frames may be identified as network errors.

Systems and methods for determining a location of a fault in a power delivery system are provided. Such a method may include receiving several single-end traveling wave fault location values and a single-end impedance fault location value based on measurements from a first intelligent electronic device at a local terminal. Based on a relationship between the single-end traveling wave fault location values, the single-end impedance fault location value, a location of the local terminal, and the location of the remote terminal, one of the several single-end traveling wave fault location values may be selected as a fault location value of highest confidence among the several single-end traveling wave fault location values.

A system comprises a first intelligent electronic device (IED) configured to receive simulated electric power delivery system measurements and test configuration settings from a computing device, transmit a signal indicative of instructions to pause normal operation to a plurality of additional IEDs, transmit a signal comprising the simulated electric power delivery system measurements and the test configuration settings to each of the plurality of additional IEDs, transmit a signal indicative of instructions to begin a test procedure according to the simulated electric power delivery system measurements and the test configuration settings to each of the plurality of additional IEDs, receive a signal indicative of test results from each of the plurality of additional IEDs, and transmit a signal indicative of instructions to resume normal operation to the plurality of additional IEDs.

A system for high-impedance differential protection for power systems using a variety of signals from the power system. A fault may be detected using filtered phase current or filtered phase voltage magnitudes from current transformers (CTs) connected in parallel by phase. A fault may be detected using filtered phase voltages and raw phase voltages from the CTs. A fault may be detected using raw phase currents and raw phase voltages from the CTs. A fault may be detected using filtered phase currents and raw phase currents. A fault may be detected using raw phase currents and raw neutral currents. The embodiments herein maintain dependability and security of a differential element even when low-class CTs are used. The embodiments herein may allow users to optimize pickup settings even when low-class CTs are used.

A distance protection element for fault coverage through a transformer that introduces a break in the zero-sequence equivalent network is disclosed herein. Voltage and current signals from a delta (low) side of the transformer are obtained and compensated using wye (high) side neutral current and nominal values. The compensated voltage and current signals are used in a distance protection element to detect faults on the wye (high) side of the transformer. The distance protection element may be implemented in a generator protection device as backup distance protection.