Abstract: Systems and methods to estimate trapped charge for a controlled automatic reclose of a power line using a ganged switching device are described herein. For example, an intelligent electronic device (IED) may calculate a voltage amount associated with trapped charge of each phase of a power line based on voltage measurements of the power line. The IED may send a signal to close a ganged switching device at a time based at least in part on the trapped charge of each phase of a power line.

Abstract: An intelligent electronic device (IED) may obtain a voltage measurement matrix based on an arrangement of a transformer in a power system. The TED may obtain a delta connection compensating angle based on the location of the circuit breaker and the transformer arrangement. The IED may obtain voltage measurements of the transformer. The TED may determine a residual flux value of the transformer based at least in part on the voltage measurements, the voltage measurement matrix and the delta connection compensating angle. The TED may send a signal to a circuit breaker of the transformer to connect the transformer to the power system based at least in part on the system voltage and residual flux value.

Abstract: Systems and methods to estimate trapped charge for a controlled automatic reclose are described herein. For example, an intelligent electronic device (IED) may calculate an analog amount of trapped charge of each phase of a power line based on voltage measurements of the power line. The IED may close a switching device of each phase at a time corresponding to a point-on-wave associated with the analog amount of trapped charge of the respective phase.

Abstract: The present disclosure illustrates the errors that are encountered when using both single-ended and double-ended normal-mode fault location calculations when a fault occurs in a pole-open condition. The disclosure provides systems and methods for accurately calculating the location of faults that occur during pole-open conditions, including single-ended approaches and double-ended approaches.

Abstract: An intelligent electronic device (IED) may obtain a residual flux of each phase of a transformer. The IED may determine a maximum difference (DIF) signal based on the residual flux and the prospective flux associated with potential close POWs of the corresponding phase. The TED may select a closing POW that results in a minimum DIF signal. The TED may send a signal to close a ganged switching device of the transformer at a time based on the selected closing POW.

Abstract: Systems and methods to estimate trapped charge for a controlled automatic reclose of a power line using a ganged switching device are described herein. For example, an intelligent electronic device (IED) may calculate a voltage amount associated with trapped charge of each phase of a power line based on voltage measurements of the power line. The IED may send a signal to close a ganged switching device at a time based at least in part on the trapped charge of each phase of a power line.

Abstract: Systems and methods to estimate trapped charge for a controlled automatic reclose are described herein. For example, an intelligent electronic device (IED) may calculate an analog amount of trapped charge of each phase of a power line based on voltage measurements of the power line. The IED may close a switching device of each phase at a time corresponding to a point-on-wave associated with the analog amount of trapped charge of the respective phase.

Abstract: The present disclosure illustrates the errors that are encountered when using both single-ended and double-ended normal-mode fault location calculations when a fault occurs in a pole-open condition. The disclosure provides systems and methods for accurately calculating the location of faults that occur during pole-open conditions, including single-ended approaches and double-ended approaches.

Abstract: The present disclosure illustrates the errors that are encountered when using both single-ended and double-ended normal-mode fault location calculations when a fault occurs in a pole-open condition. The disclosure provides systems and methods for accurately calculating the location of faults that occur during pole-open conditions, including single-ended approaches and double-ended approaches.

Abstract: The present disclosure illustrates the errors that are encountered when using both single-ended and double-ended normal-mode fault location calculations when a fault occurs in a pole-open condition. The disclosure provides systems and methods for accurately calculating the location of faults that occur during pole-open conditions, including single-ended approaches and double-ended approaches.

Abstract: A quadrilateral distance module may be used to detect faults in an electrical power system. A resistive coverage of the quadrilateral distance module may be defined by an adaptive resistance blinder. The adaptive resistance blinder may be adapted to certain power system conditions, such as forward load flow and/or reverse load flow. A forward adaptive resistance blinder may be calculated in parallel with a reverse adaptive resistance blinder. The forward adaptive resistance blinder may use a polarizing quantity adapted for forward load flow conditions, and the reverse adaptive resistance blinder may use a polarizing quantity adapted for reverse load flow conditions. Fault detection may be performed by comparing both the forward and reverse adaptive resistance blinders to power system stimulus and detecting a fault when the stimulus satisfy either blinder.

Abstract: A quadrilateral distance module may be used to detect faults in an electrical power system. A resistive coverage of the quadrilateral distance module may be defined by an adaptive resistance blinder. The adaptive resistance blinder may be adapted to certain power system conditions, such as forward load flow and/or reverse load flow. A forward adaptive resistance blinder may be calculated in parallel with a reverse adaptive resistance blinder. The forward adaptive resistance blinder may use a polarizing quantity adapted for forward load flow conditions, and the reverse adaptive resistance blinder may use a polarizing quantity adapted for reverse load flow conditions. Fault detection may be performed by comparing both the forward and reverse adaptive resistance blinders to power system stimulus and detecting a fault when the stimulus satisfy either blinder.

Abstract: A quadrilateral distance module may be used to detect faults in an electrical power system. A resistive coverage of the quadrilateral distance module may be defined by an adaptive resistance blinder. The adaptive resistance blinder may be adapted to certain power system conditions, such as forward load flow and/or reverse load flow. A forward adaptive resistance blinder may be calculated in parallel with a reverse adaptive resistance blinder. The forward adaptive resistance blinder may use a polarizing quantity adapted for forward load flow conditions, and the reverse adaptive resistance blinder may use a polarizing quantity adapted for reverse load flow conditions. Fault detection may be performed by comparing both the forward and reverse adaptive resistance blinders to power system stimulus and detecting a fault when the stimulus satisfy either blinder.

Abstract: A generator winding-to-ground fault detection system is disclosed that includes a signal injection source in electrical communication with a winding of an electric power generator via an injection transformer. The winding may be coupled to ground via a winding-to-ground path and the signal generation source may generate an injection signal capable of being injected to the winding using the injection transformer. The disclosed system may further include a protection module in communication with the signal injection source and the electric power generator configured to receive the injection signal and a signal relating to the current through the winding-to-ground path, and to determine the occurrence of a winding-to-ground fault condition based at least in part on the injection signal and the signal relating to the current through the winding-to-ground path.

Abstract: Independent frequency measurement and tracking of a signal using a measurement interval where the frequency of the signal is measured and a sampling rate is calculated, and a settling interval where the frequency of the signal is not measured. The sampling rate is calculated to correspond with the frequency of the signal and updated only after the calculation of the sampling rate in the measuring interval. The signal may be a signal of an electric power system such as a voltage waveform or a current waveform. The frequency calculation may include determination of a rate of rotation of a positive-sequence phasor of the signal.

Abstract: A system and method for acquiring phasors outside of the frequency tracking range for power protective relays. As the frequency of a power system varies from the rated frequency, phasors calculated from such samples include errors. A frequency tracking range is used to sample the signal waveform at a rate corresponding to the frequency when the frequency is within the frequency tracking range. When the frequency is outside of the frequency tracking range, the signal waveform is sampled at a rate corresponding with the maximum or minimum of the frequency tracking range depending on whether the frequency exceeds or falls below the frequency tracking range. The difference between the frequency and the minimum or maximum of the frequency tracking range is used to correct the measured phasors to result in accurate phasors.

Abstract: A generator winding-to-ground fault detection system is disclosed that includes a signal injection source in electrical communication with a winding of an electric power generator via an injection transformer. The winding may be coupled to ground via a winding-to-ground path and the signal generation source may generate an injection signal capable of being injected to the winding using the injection transformer. The disclosed system may further include a protection module in communication with the signal injection source and the electric power generator configured to receive the injection signal and a signal relating to the current through the winding-to-ground path, and to determine the occurrence of a winding-to-ground fault condition based at least in part on the injection signal and the signal relating to the current through the winding-to-ground path.

Abstract: A quadrilateral distance module may be used to detect faults in an electrical power system. A resistive coverage of the quadrilateral distance module may be defined by an adaptive resistance blinder. The adaptive resistance blinder may be adapted to certain power system conditions, such as forward load flow and/or reverse load flow. A forward adaptive resistance blinder may be calculated in parallel with a reverse adaptive resistance blinder. The forward adaptive resistance blinder may use a polarizing quantity adapted for forward load flow conditions, and the reverse adaptive resistance blinder may use a polarizing quantity adapted for reverse load flow conditions. Fault detection may comprise comparing both the forward and reverse adaptive resistance blinders to power system stimulus and detecting a fault when the stimulus satisfy either blinder.

Abstract: An apparatus and method detects an open condition of a grounding path provided by a rotor grounding brush electrically connecting a rotor body of a rotor to electrical ground. The rotor includes an insulated field winding wrapped around the rotor body and is configured to generate a magnetic field upon receipt of an exciter voltage across lower and upper extremities of the insulated field winding. The method includes applying a square wave voltage signal to a second end of each of a first and a second buffer resistor, where a first end of each of the buffer resistors is operatively connected to respective upper and lower leads of the exciter voltage source, and calculating the total capacitance between the insulated field winding and electrical ground. The total capacitance when compared to a pre-selected capacitance value is determinative of the absence of the grounding path.

Abstract: Independent frequency measurement and tracking of a signal using a measurement interval where the frequency of the signal is measured and a sampling rate is calculated, and a settling interval where the frequency of the signal is not measured. The sampling rate is calculated to correspond with the frequency of the signal and updated only after the calculation of the sampling rate in the measuring interval. The signal may be a signal of an electric power system such as a voltage waveform or a current waveform. The frequency calculation may include determination of a rate of rotation of a positive-sequence phasor of the signal.