Abstract: Protection of an electrical generator includes determining a rotor and stator components using rotor and stator electrical signals, calculating a unbalance and/or differential component using the stator and rotor components, and determining a stator or rotor fault based on the unbalance and/or differential component. Further, the faulted phase and/or zone of a stator fault may be determined using the stator positive sequence voltage and negative sequence current.

Abstract: The present disclosure provides systems and methods for generating a system-wide event report for electrical power delivery systems. A monitoring device within the power system may generate a key message upon the occurrence of a predetermined condition. A master IED within the power system may generate and/or transmit a system-wide key message to a plurality of monitoring IEDs within the power system. Digital process bus data, continuously recorded by a plurality of monitoring IEDs within the power system, may be saved locally by each monitoring IED within the power system and retrieved by a master IED within the power system. Alternatively, digital process bus data may be transmitted to a master IED and saved locally. A software and/or hardware module may be used to merge the local reports into a system-wide event report.

Abstract: The present disclosure relates to systems and methods for detecting transient high-torque events associated with rotating machinery in an electric power system. In one embodiment, a relay may comprise an electrical parameters module configured to receive a representation of a voltage and a current at a terminal of rotating machinery in an electric power system. A torque calculation module may be configured to continuously determine a calculated torque value for the rotating machinery using the representation of the voltage and the current at the terminal of the rotating machinery; and to compare each calculated torque value to a threshold. An action module may be configured to generate an alarm when the calculated torque value exceeds the threshold. A log module may be configured to generate a log comprising a peak of the calculated torque value and a time at which the peak torque value occurs.

Abstract: Disclosed herein are a variety of systems and methods related to detection of a cross-country fault in an electrical power system. In one embodiment, a system consistent with the present disclosure may be configured to monitor electrical parameters in the electrical power system. The system may determine when a voltage magnitude of one phase exceeds a first voltage threshold. The one phase that exceeds the first voltage threshold may be identified as an un-faulted phase. The system may further be configured to determine that the voltage magnitude of the un-faulted phase exceeds a second threshold based on a zero-sequence voltage. The system may further be configured to determine that a phase angle between the un-faulted phase and the zero-sequence voltage is within a range. A protective action to clear the cross-country fault condition may be implemented upon identification of a cross-country fault.

Abstract: The present disclosure provides systems and methods for generating a system-wide event report for electrical power delivery systems. A monitoring device within the power system may generate a key message upon the occurrence of a predetermined condition. A master IED within the power system may generate and/or transmit a system-wide key message to a plurality of monitoring IEDs within the power system. Digital process bus data, continuously recorded by a plurality of monitoring IEDs within the power system, may be saved locally by each monitoring IED within the power system and retrieved by a master IED within the power system. Alternatively, digital process bus data may be transmitted to a master IED and saved locally. A software and/or hardware module may be used to merge the local reports into a system-wide event report.

Abstract: Systems and Methods are disclosed for providing measurement data redundancy to intelligent electronic devices (IEDs) in an electric power system, without additional redundant components. In various embodiments, a first measurement device obtains measurement data from a first portion of the electric power delivery system. A second measurement device obtains measurement data from a second portion of the electric power delivery system. A first IED monitors the first portion of the electric power delivery system based on measurement data associated with the first portion of the electric power delivery system, and a second IED monitors the second portion of the electric power delivery system based on measurement data associated with the second portion of the electric power delivery system.

Abstract: The present disclosure pertains to systems and methods for supervising protective elements in electric power systems. In one embodiment, a system may be configured to selectively enable a protective action an electric power system. The system may include a data acquisition subsystem receive a plurality of representations of electrical conditions associated with at least a portion of the electric power delivery system. An incremental quantities module may calculate incremental quantities from the plurality of representations. A protective module may be configured to detect an event, to determine an incremental quantities value during the event, and to determine a time-varying threshold. The incremental quantities value during the event may be compared with the time-varying threshold, and a protective action module may be enabled to implement a protective action when the value of the incremental quantities value during the event exceeds the time-varying threshold.

Abstract: The present disclosure provides systems and methods for validating electric power delivery monitoring systems, including, but not limited to, current transformers (CTs) and voltage potential transformers (PTs). According to various embodiments, a first IED monitors a portion of an electric power delivery system via one or more CTs and/or PTs. A second IED monitors the portion of the electric power delivery system via one or more additional CTs and/or PTs. Each IED may generate an event report, containing measurement data, associated with each respective measurement equipment. A validation module may compare the event reports in order to validate that the IEDs and/or the underlying measurement equipment are functioning correctly. According to various embodiments, the validation module may be configured to align the event reports from two IEDs using an event trigger common to both IEDs.

Abstract: Protection of an electrical generator includes determining a rotor and stator components using rotor and stator electrical signals, calculating a unbalance and/or differential component using the stator and rotor components, and determining a stator or rotor fault based on the unbalance and/or differential component. Further, the faulted phase and/or zone of a stator fault may be determined using the stator positive sequence voltage and negative sequence current.

Abstract: Detection of a fault in an ungrounded electric power distribution system that includes a plurality of feeders and buses is disclosed herein. Embodiments consistent with the present disclosure may monitor an electrical parameter associated with each of a plurality of feeders and buses in the ungrounded electric power distribution system. An incremental change in the monitored electrical parameters may be determined using the monitored electrical parameter. Further, the incremental change may be associated with a first sub-set of the plurality of feeders. Torque values for the feeders may be calculated using a reference quantity from the bus first exhibiting an incremental change above a threshold. A feeder having the largest incremental change in the first sub-set of the plurality of feeders may be identified. A fault may be identified based on the torque and the incremental change.

Abstract: Disclosed herein are systems and methods for leveraging the inherent redundancy of electrical measurement inputs available to microprocessor-based intelligent electronic devices (IEDs). Specifically, an IED may receive a plurality of electrical measurements associated with an electric power delivery system, such as measurements associated with a generator. A first protection module may be configured to detect a first type of electrical disturbance using a first subset of the plurality of electrical measurements. A second protection module may be configured to detect a second type of electrical disturbance using a second subset of the plurality of electrical measurements. A first redundant protection module may be configured to verify the detection of the first type of electrical disturbance using at least a portion of the second subset of the plurality of electrical measurements.

Abstract: Detection of a fault in an ungrounded electric power distribution system that includes a plurality of feeders and buses is disclosed herein. Embodiments consistent with the present disclosure may monitor an electrical parameter associated with each of a plurality of feeders and buses in the ungrounded electric power distribution system. An incremental change in the monitored electrical parameters may be determined using the monitored electrical parameter. Further, the incremental change may be associated with a first sub-set of the plurality of feeders. Torque values for the feeders may be calculated using a reference quantity from the bus first exhibiting an incremental change above a threshold. A feeder having the largest incremental change in the first sub-set of the plurality of feeders may be identified. A fault may be identified based on the torque and the incremental change.

Abstract: A system for controlling and automating an electric power delivery system by executing time coordinated instruction sets to achieve a desired result. A communication master may implement the execution of time coordinated instruction sets in a variety of circumstances. The communication may be embodied as an automation controller in communication with intelligent electronic devices (IEDs). The communication master may also be embodied as an IED that is configured to coordinate the actions of other IEDs. The time coordinated instruction sets may include steps for checking status of power system equipment before executing. The time coordinated instruction sets may include reactionary steps to execute if one of the steps fails. The time coordinated instruction sets may also be implemented based on a condition detected in the electric power delivery system, or may be implemented through high level systems, such as a SCADA system or a wide area control and situational awareness system.

Abstract: Current differential protection is provided for a multi-terminal power apparatus, such as a power transmission line. Currents measured at each of the multiple terminals are used to calculate a differential current and a restraining current, which are then converted into a first equivalent current and a second equivalent current of an equivalent two-terminal power apparatus. In the equivalent two-terminal power apparatus, a differential current derived from the first and second equivalent currents is substantially equal to the differential current of the original multi-terminal power apparatus. Similarly, a restraining current derived from the first and second equivalent currents is substantially equal to the restraining current of the original multi-terminal power apparatus. The first and second equivalent currents may be used in an alpha plane analysis to determine whether or not to trip the multi-terminal power apparatus.

Abstract: A line current differential protection system that uses an external time reference continues providing protection to a power apparatus upon the loss of the external time reference. An external time reference synchronization mode and a channel based synchronization mode may be selectively applied on a per channel basis such that only those channels in the system that are not guaranteed to stay symmetrical use external time reference synchronization.

Abstract: Transformer differential protection is provided by measuring a plurality of currents corresponding to a first set of windings and a second set of windings of a transformer, and compensating the currents based on their respective flows through either the first set of windings or the second set of windings. The compensated currents may be intentionally augmented to compensate for magnetizing inrush and/or stationary overexcitation conditions associated with the transformer. Augmentation based on stationary overexcitation, for example, may be based on either harmonic restraint or an addition of a V/Hz ratio to a restraining signal. A complex current ratio is calculated corresponding to the plurality of compensated currents. The complex current ratio may be based on a two-terminal equivalent power apparatus. Then, an alpha plane analysis is applied to the complex current ratio. Based on the alpha plane analysis, a power apparatus that includes the transformer is selectively tripped.

Abstract: Disclosed herein are systems and methods for leveraging the inherent redundancy of electrical measurement inputs available to microprocessor-based intelligent electronic devices (IEDs). Specifically, an IED may receive a plurality of electrical measurements associated with an electric power delivery system, such as measurements associated with a generator. A first protection module may be configured to detect a first type of electrical disturbance using a first subset of the plurality of electrical measurements. A second protection module may be configured to detect a second type of electrical disturbance using a second subset of the plurality of electrical measurements. A first redundant protection module may be configured to verify the detection of the first type of electrical disturbance using at least a portion of the second subset of the plurality of electrical measurements.

Abstract: A system for controlling and automating an electric power delivery system by executing time coordinated instruction sets to achieve a desired result. A communication master may implement the execution of time coordinated instruction sets in a variety of circumstances. The communication may be embodied as an automation controller in communication with intelligent electronic devices (IEDs). The communication master may also be embodied as an IED that is configured to coordinate the actions of other IEDs. The time coordinated instruction sets may include steps for checking status of power system equipment before executing. The time coordinated instruction sets may include reactionary steps to execute if one of the steps fails. The time coordinated instruction sets may also be implemented based on a condition detected in the electric power delivery system, or may be implemented through high level systems, such as a SCADA system or a wide area control and situational awareness system.

Abstract: A power system may comprise two or more transformers operating in parallel. A voltage differential may exist between the transformers, which may create a circulating current in the power system. The system voltage of the power system may be modified by performing a tap change operation on one or more of the transformers. The tap change operation may be configured to minimize the circulating current. The circulating current may be minimized by determining the bias between the transformers using an angular difference between the transformer currents. The angular difference may be calculated using time-aligned measurement data. A tap change operation configured to modify the system voltage, while minimizing circulating current, may be determined using the transformer bias.

Abstract: Current differential protection with charging current compensation is provided for a power apparatus, such as a power transmission line. Individual terminals dynamically determine their respective contributions, if any, to the charging current compensation value as availability of one or more voltage sources dynamically changes within the power apparatus. Respective terminals calculate local contributions to a charging current compensation value based on local voltage measurements. A loss of a voltage source is handled by adjusting multipliers for the remaining compensation points to reflect the total charging current. A local contribution is suppressed when the local voltage source is no longer available. After applying the local contributions, an alpha plane analysis may be used to determine when to trip the power apparatus.