Schweitzer Engineering Laboratories, Inc.

Aep Transmission Holding Company, LLC

Yanfeng Gong

Armando Guzman-Casillas

Mangapathirao Venkata Mynam

Normann Fischer

Kanchanrao Gangadhar Dase

Richard M Edge

Gandhali P Juvekar

Yiyan Xue

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.

Single phase broken conductor detection

A method and a system are used to monitor electrical measurements of a power system during a period of time. The system calculates and analyzes incremental quantities based on the electrical measurements of the power system. The incremental quantities are used to identify a conductor breaking fault in the power system. Instructions are sent out to activate certain actions (e.g., protective actions) based on the identified fault and the type of fault. The system operates continuously to provide real-time monitoring and fault identification.

Single-ended broken conductor detection logic using incremental quantities

Relay devices and methods of use for detecting and reacting to subsynchronous oscillation events in electrical energy generation and transmission systems, such as but not limited to, subsynchronous control interactions between wind-turbine generators and series-compensated transmission lines.

Subsynchronous oscillation relay

Fault location on a non-homogeneous electric power line that includes a plurality of sections by determining a section in which negative-sequence voltage magnitude profiles calculated from each terminal of the power line intersect. The fault location may determine the faulted section and determine the location of the fault within the faulted section. To determine the fault location, the negative-sequence voltage magnitude profiles may be calculated from measurements taken at each terminal of the power line and compared to determine a point where the profiles intersect. The profiles may be calculated using power line properties and measurements from each terminal.

Fault location in a non-homogeneous electric power line

Disclosed herein are systems and methods for identifying a fault type in an electric power delivery system using an angle difference between a total zero-sequence current and a total negative-sequence current and a comparison of phase-to-phase currents against a threshold. The angle difference falls into one of a number of predetermined angle difference sectors. Each sector is associated with a phase-to-ground fault type and a phase-to-phase-to-ground fault type or two phase-to-phase-to-ground fault types. The phase-to-phase current(s) of the indicated phase-to-phase-to-ground fault type(s) associated with the sector are compared with a threshold to determine which of the fault types of the sector is the actual fault type. The threshold may be a multiple of a maximum phase-to-phase current.

Fault-type identification for electric power delivery systems

Accurately calculating location of a phase-to-phase fault even on a branched, non-homogenous, radial electric power distribution system. The calculation includes determining a calculated reactance to the fault without using positive-sequence current measurements, and uses the line parameters to determine locations on the system that match the calculated reactance to the fault. The calculation may further include a determination of faulted phase and eliminate fault location possibilities based on absence of the faulted phase at those locations.

Fault location in electric power delivery systems

Accurately calculating location of a fault even on a branched, non-homogenous, radial electric power distribution system. The calculation includes determining a calculated reactance or impedance to the fault, and uses the line parameters to determine locations on the system that match the calculated reactance to the fault. The calculation may further include a determination of faulted phase and eliminate fault location possibilities based on absence of the faulted phase at those locations. The calculation may further use data reported from line monitors such as faulted circuit indicators (FCIs).

A power system oscillation detection device is provided for use in an electric power system. A plurality of sample signals are acquired from the electrical power system via a plurality of intelligent electronic devices (IEDs) in communication with the power system. The power system oscillation detection device includes a real-time modal analysis module, a real-time mode identification module, and real-time decision and control logic. The real-time modal analysis module calculates modes of at least one of the signals, each mode including mode information. The real-time mode identification module together with the real-time decision and control logic determines, from the mode information, whether there is an undesirable oscillation in the electric power system and activates a remedial action.

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Pullman, WA, United States of America

Yanfeng Gong