Abstract: A system and method to authenticate users on a computing system using a free text behavioral biometric method by recording on the computer system a dataset for each user to be authenticated to create a user profile for each user to be authenticated, each data set comprising a plurality of free-text keystrokes entered by a respective user on a computer that is part of the computing system, and storing each user profile in the memory, subsequently collecting the keystrokes of a user to be authenticated as the user enters text on a keyboard connected to the computing system, creating a plurality of graphs based on the collection of keystrokes entered by the user and calculating n instance based tail area density (ITAD) metric, and then combining the ITAD metric for each graph duration into a single similarity score.

Abstract: The present disclosure relates to systems and methods tracking an alternating current frequency in an electric power system. In one embodiment, a system may include a waveform receiving subsystem to receive a representation of a current waveform. A sampling subsystem may sample the representation of a current waveform at a first estimated frequency and generate a sampled representation of the current waveform. A filtered and sampled representation of the current waveform may be generated using a filter subsystem. A period subsystem may determine an estimated period of the filtered and sampled representation of the current waveform. A frequency determination subsystem may determine a second estimated frequency based on the estimated period. The second estimated frequency may then be used by the sampling subsystem in a subsequent iteration to sample a subsequent representation of the current waveform.

Abstract: Disclosed herein are systems for determining a broken conductor condition in a multiple-phase electric power delivery system. It has been observed that broken conductors pose a safety concern when occurring in the presence of people or vulnerable environmental conditions. Broken conductor conditions disclosed herein may be used to detect and trip the phase with the broken conductor, thus reducing or even eliminating the safety risk. Further, a distance to the opening may be determined.

Abstract: Systems and methods including improving availability of protection of an electric power delivery system even upon unavailability of power system signals. Such protection relays may provide protection using signals from the power system and provide the signals to an integrator or another device. Upon unavailability of power system signals to a protection relay, the integrator sends substitute power system signals may be provided to the protection relay. The protection relay may continue to provide protection using the substitute power system signals.

Abstract: Systems and methods including improving availability of protection of an electric power delivery system even upon unavailability of power system signals. Such protection relays may provide protection using signals from the power system and provide the signals to an integrator or another device. Upon unavailability of power system signals to a protection relay, the integrator sends substitute power system signals may be provided to the protection relay. The protection relay may continue to provide protection using the substitute power system signals.

Abstract: Disclosed herein are systems for determining a broken conductor condition in a multiple-phase electric power delivery system. It has been observed that broken conductors pose a safety concern when occurring in the presence of people or vulnerable environmental conditions. Broken conductor conditions disclosed herein may be used to detect and trip the phase with the broken conductor, thus reducing or even eliminating the safety risk. Further, a distance to the opening may be determined.

Abstract: Systems and methods are presented for detecting high-impedance faults (HIFs) in an electric power delivery system using a plurality of coordinated high-impedance fault detection systems. In certain embodiments, a method for HIFs may include receiving first and second current representations associated with first and second locations of the electric power delivery system respectively. Based on at least one of the first and second current representations, the occurrence of an HIF may be determined. A relative location of the HIF may be determined based on a relative amount of interharmonic content associated with an HIF included in the first and second current representations, and a protective action may be taken based on the determined relative location.

Abstract: Systems and methods are presented for detecting high-impedance faults (HIFs) in an electric power delivery system using a plurality of coordinated high-impedance fault detection systems. In certain embodiments, a method for HIFs may include receiving first and second current representations associated with first and second locations of the electric power delivery system respectively. Based on at least one of the first and second current representations, the occurrence of an HIF may be determined. A relative location of the HIF may be determined based on a relative amount of interharmonic content associated with an HIF included in the first and second current representations, and a protective action may be taken based on the determined relative location.

Abstract: The system and methods monitor odd harmonics within a power distribution system quantity using a special digital filter. A normal level of odd harmonics for the monitored quantity is established. Over predetermined time periods, the odd harmonics within the power distribution quantity are compared to the normal level, and a determination of whether a high-impedance fault is present in the monitored power distribution system is made.

Abstract: The apparatus and methods calculate a plurality of sum of differences for a power distribution system quantity with a sum of difference filter, provide a set of predetermined blocking conditions, provide a trending and memory with an output, generate a set threshold with an adaptive tuning algorithm; establish a reference based upon the plurality of power distribution quantities differences from the one-cycle difference filter and the set threshold, calculate a ratio of the difference between the plurality of sum of differences from the sum of difference filter and the reference, memorize a time and form a trend output if the ratio of the difference exceeds the set threshold, and determine the existence of a high-impedance fault with decision logic based on the trend output and the set of predetermined blocking conditions.

Abstract: A system and method for accomplishing power swing blocking and unstable power swing tripping schemes during disturbances of electrical networks is disclosed. The disclosed system and method eliminates the requirement of stability studies. The no-setting scheme utilizes the swing center voltage of the electrical network to carry out its functions.

Abstract: The system and methods monitor odd harmonics within a power distribution system quantity using a special digital filter. A normal level of odd harmonics for the monitored quantity is established. Over predetermined time periods, the odd harmonics within the power distribution quantity are compared to the normal level, and a determination of whether a high-impedance fault is present in the monitored power distribution system is made.

Abstract: The apparatus and methods calculate a plurality of sum of differences for a power distribution system quantity with a sum of difference filter, provide a set of predetermined blocking conditions, provide a trending and memory with an output, generate a set threshold with an adaptive tuning algorithm; establish a reference based upon the plurality of power distribution quantities differences from the one-cycle difference filter and the set threshold, calculate a ratio of the difference between the plurality of sum of differences from the sum of difference filter and the reference, memorize a time and form a trend output if the ratio of the difference exceeds the set threshold, and determine the existence of a high-impedance fault with decision logic based on the trend output and the set of predetermined blocking conditions.

Abstract: A system for maintaining fault-type selection during an out-of-step condition is provided comprising an element for calculating the element reach M; an element for fault type selection; an element for out-of-step detection and blocking; and an element for distinguishing between single-phase-to-ground faults and double-phase-to-ground faults. Single-phase-to-ground faults are distinguished from double-phase-to-ground faults through either a derivative or integration element.

Abstract: A system and method for accomplishing power swing blocking and unstable power swing tripping schemes during disturbances of electrical networks is disclosed. The disclosed system and method eliminates the requirement of stability studies. The no-setting scheme utilizes the swing center voltage of the electrical network to carry out its functions.

Abstract: The apparatus detects an out-of-step condition following the clearing of an external multi-phase fault in a protective relay. The apparatus includes a circuit which detects the presence of an external multi-phase fault on the power line and a timing circuit for readying an out-of-step logic detection circuit in the protective relay if the external fault remains for a pre-selected period of time. An out-of-step condition is declared and a signal blocking operation of selected distance elements in the protective relay is produced if the positive sequence impedance on the line remains inside an outer protection zone boundary in the impedance plane for a selected period of time, wherein the out-of-step blocking signal continues as long as the positive sequence impedance remains inside the second boundary.

Abstract: A system for detecting ground faults in a compensated electric power distribution network includes the determination of zero sequence voltage (V0) and zero sequence current (I0) on a power line and calculating the zero sequence conductance (G0) therefrom. The operation of the conductance calculation circuit occurs only under selected power line conditions involving minimum values of zero sequence voltage, zero sequence current and positive sequence voltage, to ensure the accuracy of a fault direction determination. The conductance values are processed on an adaptive basis in which the difference between the most recent conductance value and a conductance value from a selected previous point in time is determined and then compared against threshold values to make forward and reverse fault declarations.

Abstract: At least two different time constants are used to produce the polarizing memory reference voltage which in turn is used in a protective relay for power transmission lines. For most conditions, a relative short time constant of 1.75 cycles is used, while under other specific conditions, determined automatically, a longer time constant of 15.75 cycles is used.

Abstract: An out-of-step blocking circuit is established with two additional zones in the impedance plane, with the circuit determining the time that the positive sequence impedance takes to move between the two zones. The distance elements for selected zones of protection for the relay are blocked if the impedance moves between the two zones at a rate less than a first threshold. However, a trip signal results if the rate of change is greater than the first threshold but less than a second threshold, indicating an unstable swing. Further, an inner blinder zone is established in the impedance plane within the additional two zones of protection. If the positive sequence impedance entering that zone does not move from that zone within a certain time during an otherwise out-of-step condition, the blocking signals are terminated.

Abstract: The voltage and current conditions on a power transmission line are monitored to determine the coincidence of a low voltage condition and a lack of a high current condition. The coincidence of those two conditions is indicative of a CCVT transient, and the tripping action from zone 1 distance elements is delayed for a period of 1.375 cycles. The tripping delay is supervised by a fault impedance determination, which, if a threshold is exceeded, the remaining portion of the time delay is eliminated, so that a trip is allowed if the time delay period has not expired.