Abstract: Protection of shunt capacitor banks in electric power delivery systems using protection settings determined by the protection device or an independent system using capacitor bank arrangement data is described herein. Capacitor bank arrangement data may be entered into an intelligent electronic device (IED). The IED may determine protection settings for the capacitor bank arrangement and for fail-open and fail-short scenarios using the arrangement data. The protection settings may be loaded into a protection element, which applies protection using signals from the power system. Upon detection of an unbalance condition, the IED may effect a protective action by opening a circuit breaker to disconnect the capacitor bank from the power system.

Abstract: Protection of an electric power delivery system using a traveling wave overcurrent element is disclosed herein. A maximum traveling wave mode among the alpha and beta modes is selected and compared with a traveling wave overcurrent threshold to determine a traveling wave overcurrent. Traveling wave overcurrent protection may be enabled depending on a termination status of the protected electric power delivery system. When a remote terminal is terminated on high surge impedance, a local protection system may use local traveling wave current quantities to determine a traveling wave overcurrent, and the traveling wave overcurrent may be used for line protection. Systems for detecting a termination status use local and remote current quantities.

Abstract: Distance protection for electric power delivery systems that include an unconventional source is disclosed herein using apparent impedance independent of memory and cross-phase polarizing. The apparent impedance may be compared with an offset distance operating characteristic. Fault direction is determined by using zero-sequence ground directional logic for phase-to-ground faults. For phase-to-phase faults, fault direction is determined using weak-infeed directional logic. Fault direction may further use incremental quantity directional principles. The distance protection may further determine a faulted loop using voltage logic. The distance protection may select between traditional distance protection and the methods described herein based on the current feeding the fault.

Abstract: Distance protection for electric power delivery systems that include an unconventional source is disclosed herein using apparent impedance independent of memory and cross-phase polarizing. The apparent impedance may be compared with an offset distance operating characteristic. Fault direction is determined by using zero-sequence ground directional logic for phase-to-ground faults. For phase-to-phase faults, fault direction is determined using weak-infeed directional logic. Fault direction may further use incremental quantity directional principles. The distance protection may further determine a faulted loop using voltage logic. The distance protection may select between traditional distance protection and the methods described herein based on the current feeding the fault.

Abstract: Protection of an electric power delivery system using a traveling wave overcurrent element is disclosed herein. A maximum traveling wave mode among the alpha and beta modes is selected and compared with a traveling wave overcurrent threshold to determine a traveling wave overcurrent. Traveling wave overcurrent protection may be enabled depending on a termination status of the protected electric power delivery system. When a remote terminal is terminated on high surge impedance, a local protection system may use local traveling wave current quantities to determine a traveling wave overcurrent, and the traveling wave overcurrent may be used for line protection. Systems for detecting a termination status use local and remote current quantities.

Abstract: Phase selection for traveling wave fault detection systems is disclosed herein. Intelligent electronic devices (IEDs) may be used to monitor and protect electric power delivery systems by detecting and acting upon traveling waves. A phase of the electric power delivery system may be selected based on the relative polarity of the traveling waves detected. The amplitude and/or polarity of the selected phase may be compared with the amplitudes and/or polarities of the other phases to determine a fault condition. For instance, the IED may determine a single-phase-to-ground fault based on the relative polarities and magnitudes of the detected traveling waves, send a protective action to the identified faulted phase, and/or continue to monitor the system for a continuation of the event or identification of a different event, such as a three-phase fault, using incremental quantities.

Abstract: The present disclosure relates to determining locations of low-energy events on power lines. For example, an IED may receiving an input signal indicating a local electrical condition of a power line. The IED may detect traveling waves on the power line based on the local electrical condition. The IED may detect traveling waves on the power line based on the local and remote electrical conditions. The IED may determine that the traveling waves are associated with a low-energy event. The IED may determine the location of the low-energy event on the power line based at least in part on the traveling waves.

Abstract: Distance protection for electric power systems disclosed herein uses an operating signal and a sequence polarizing signal made up of a supervised sequence current and a supervised sequence voltage. The polarizing signal may be determined based on the fault type and may be weighted toward sequence currents or sequence voltages depending on the power system conditions. For phase-to-ground faults, the sequence currents may include negative-sequence and zero-sequence currents. For phase-to-phase faults, the sequence currents may include negative-sequence currents. The current portion of the sequence polarizing signal may be weighted based on detection of insufficient negative-sequence current magnitude, standing unbalance, current transformer saturation, open pole, three-phase fault, and the like. The distance elements described herein provides improved protection during real-world power system conditions and changes.

Abstract: Distance protection for electric power systems disclosed herein uses an operating signal and a sequence polarizing signal made up of a supervised sequence current and a supervised sequence voltage. The polarizing signal may be determined based on the fault type and may be weighted toward sequence currents or sequence voltages depending on the power system conditions. For phase-to-ground faults, the sequence currents may include negative-sequence and zero-sequence currents. For phase-to-phase faults, the sequence currents may include negative-sequence currents. The current portion of the sequence polarizing signal may be weighted based on detection of insufficient negative-sequence current magnitude, standing unbalance, current transformer saturation, open pole, three-phase fault, and the like. The distance elements described herein provides improved protection during real-world power system conditions and changes.

Abstract: Disclosed herein are systems and methods for estimating a period and frequency of a waveform. In one embodiment a system may comprise an input configured to receive a signal comprising a representation of the waveform. A period determination subsystem may calculate an estimated period of the signal based on a period determination function. An estimated period adjustment subsystem may determine an adjustment to the estimated period based on a result of the period determination function. A quality indicator subsystem configured to evaluate a measurement quality indictor function based on the estimated period, and to selectively update the period of the waveform based on the measurement quality indicator. A control action subsystem configured to implement a control action based on the period of the waveform.

Abstract: The present disclosure pertains to systems and methods for monitoring traveling waves in an electric power system. In various embodiments, a data acquisition subsystem may acquire electric power system signals. A traveling wave detection subsystem may detect two or more traveling waves based on the electric power system signals and determine a location of an event triggering the traveling waves. A traveling wave security subsystem may selectively generate a restraining signal based on the location of the event as within a blocking zone. A protection action subsystem may implement a protective action when the location is outside of a blocking zone. In various embodiments, a protective action will not be implemented for traveling waves launched from known locations of switching devices operating normally. Further, protective actions may be restrained if a magnitude of a traveling wave differs from an expected value based on a pre-fault voltage.

Abstract: The present disclosure pertains to systems and methods for detecting traveling waves in electric power delivery systems. In one embodiment, a system comprises a capacitance-coupled voltage transformer (CCVT) in electrical communication with the electric power delivery system, the CCVT comprising a stack of capacitors and an electrical contact to a first ground connection. Electrical signals from accessible portions of the CCVT are used to detect traveling waves. Current and/or voltage signals may be used. In various embodiments, a single current may be used. The traveling waves may be used to detect a fault on the electric power delivery system.

Abstract: An electric power delivery system may be protected upon occurrence of a fault condition by the systems and methods disclosed herein by detecting the fault condition and signaling a protective action before the overcurrent condition reaches the protective equipment. The protective action may be an opening of a circuit breaker or engagement of a fault current limiter. The overcurrent condition may be a non-steady-state condition. The fault may be detected using traveling wave or incremental quantity techniques.

Abstract: The present disclosure pertains to systems and methods for analyzing traveling waves in an electric power delivery system. In one embodiment, a system may comprise a traveling wave identification subsystem to receive electric power system signals and identify a plurality of incident, reflected, and transmitted traveling waves. A first traveling wave may be selected from the incident and transmitted traveling waves, and a first distortion may be determined. A second traveling wave subsequent to the first traveling wave, may selected from the incident traveling waves and a second distortion may be determined. A traveling wave analysis subsystem may compare the first distortion and the second distortion and determine whether the first distortion is consistent with the second distortion. A protective action subsystem may implement a protective action based on a first determination that the first distortion is consistent with the second distortion.

Abstract: The present disclosure pertains to systems and methods to detect faults in electric power delivery systems. In one embodiment, a data acquisition system may acquire a plurality of electric power delivery system signals from an electric power transmission line. A traveling wave system may detect a traveling wave based on the plurality of electric power delivery system signals received from the data acquisition system. The traveling wave may be analyzed using a first mode to determine a first mode arrival time and using a second mode to determine a second mode arrival time. A time difference between the first mode arrival time and the second mode arrival time may be determined. A fault location system may estimate or confirm a location of the fault based on the time difference. A protection action module may implement a protective action based on the location of the fault.

Abstract: Polarizing signals for electric power system directional overcurrent and distance protection are disclosed herein. The polarizing signal may be determined using a power system tracking signal, generated using a synchronous reference frame to track to a pre-fault voltage, and maintained using a phase-locked loop. The power system tracking signal may be used for a time after a voltage signal is lost, after which a self-polarizing signal may be used. Where voltage signals are not available, a current may be used to generate the polarizing signal.

Abstract: Variable window filtered power system signals for electric power system monitoring and protection operations of an electric power system are provided herein. Upon detection of a power system disturbance, the filter window is decreased after a predetermined resize delay such that pre-disturbance samples are not included in the new window. As additional samples are obtained, the filter window grows to include new samples until the window reaches an initial filter window length. Gain and group delay correction factors accounting for window size and signal frequency are approximated.

Abstract: The present disclosure pertains to systems and methods for detecting traveling waves in electric power delivery systems. In one embodiment, a system comprises a capacitance-coupled voltage transformer (CCVT) in electrical communication with the electric power delivery system, the CCVT comprising a stack of capacitors and an electrical contact to a first ground connection. Electrical signals from accessible portions of the CCVT are used to detect traveling waves. Current and/or voltage signals may be used. In various embodiments, a single current may be used. The traveling waves may be used to detect a fault on the electric power delivery system.

Abstract: Fault-type identification using composite signals composed from symmetrical component voltages and currents is described herein. Angular differences between negative-sequence composite signals and zero-sequence composite signals are used to determine a single-line-to-ground fault, and the faulted phase. Angular differences between positive sequence voltage and negative-sequence composite signals are used to determine a multiple-line-to-ground fault, and the faulted phases. Negative-sequence composite signals and zero-sequence composite signals are calculated using combinations of negative-sequence currents and voltages and zero-sequence voltages and currents, respectively.

Abstract: The present disclosure pertains to systems and methods for detecting faults in an electric power delivery system. In one embodiment, system may include a data acquisition subsystem configured to receive a plurality of representations of electrical conditions. The system may also include an incremental quantities subsystem configured to calculate an incremental current quantity and an incremental voltage quantity based on the plurality of representations. A fault detection subsystem may be configured to determine a fault type based on the incremental current quantity and the incremental voltage quantity, to select an applicable loop quantity, and to declare a fault based on the applicable loop quantity, the incremental voltage quantity, and the incremental current quantity. A protective action subsystem may implement a protective action based on the declaration of the fault.