Abstract: A sensing device incudes: a housing including an electrical interface and a surface, the surface defining a first connection interface and a second connection interface, the first connection interface configured to connect the housing to a bushing, the second connection interface configured to connect the housing to a separate electrical device, the electrical interface being configured to electrically connect to an electrical conductor of the electrical device; a capacitive voltage sensor including a plurality of capacitors, at least one of the plurality of capacitors being in a first portion of the housing, the at least one capacitor in the first portion of the housing and at least one other capacitor of the plurality of capacitors arranged relative to each other to form a capacitive divider; and a current sensor in a second portion of the housing.

Abstract: Techniques for detecting an inrush current in a power transformer in are disclosed. For example, the presence of an inrush current on a current path in a power transformer may be determined by receiving a signal from a Rogowski coil positioned on a current path of a power transformer, the signal corresponding to a current flowing in the current path; sampling the received signal to produce samples of the received signal; and analyzing the samples of the received signal relative to at least two criteria to determine whether an inrush current is present. When an inrush current is present, operation of a protective relay is blocked.

Abstract: Techniques for detecting an inrush current in a power transformer in are disclosed. For example, the presence of an inrush current on a current path in a power transformer may be determined by receiving a signal from a Rogowski coil positioned on a current path of a power transformer, the signal corresponding to a current flowing in the current path; sampling the received signal to produce samples of the received signal; and analyzing the samples of the received signal relative to at least two criteria to determine whether an inrush current is present. When an inrush current is present, operation of a protective relay is blocked.

Abstract: A method, device, and system for mitigating the effect of a power spike on a protective device. The device can receive an input signal and determine whether the input signal exceeds a threshold value. If so, the device simultaneously starts an initial time period and starts a latch time period, where the latch time period is greater than the initial time period. During the initial time period, the device replaces the input signal with a set value signal. After the initial time period ends and during the remainder of the latch time period, the device prevents the input signal from being replaced by the set value signal. If, during the remainder of the latch time period, the input signal exceeds the threshold value, a trip signal may be generated by a protective device.

Abstract: A method, device, and system for mitigating the effect of a power spike on a protective device. The device can receive an input signal and determine whether the input signal exceeds a threshold value. If so, the device simultaneously starts an initial time period and starts a latch time period, where the latch time period is greater than the initial time period. During the initial time period, the device replaces the input signal with a set value signal. After the initial time period ends and during the remainder of the latch time period, the device prevents the input signal from being replaced by the set value signal. If, during the remainder of the latch time period, the input signal exceeds the threshold value, a trip signal may be generated by a protective device.

Abstract: A method, device, and system for detecting a fault for a protective device. The device can receive an input signal and detect a power spike in the input signal. If a power spike is detected in the input signal, the device simultaneously disables the trip mechanism for one or more protective devices and starts a time period. During the remainder of the time period, the device compares the input signal and the threshold value. If, during the remainder of the time period, the input signal exceeds the threshold value, and if the fault originates within a region between the multiple sensing devices, then the trip mechanism for each protective device is again enabled.

Abstract: An apparatus includes at least one Rogowski coil and a processor. The at least one Rogowski coil is positioned within an electrical power distribution network to detect a first traveling wave current caused by a fault on an electrical power transmission line of the network, generate a first signal indicative of detection of the first traveling wave, detect a second traveling wave current caused by the fault on the transmission line, and generate a second signal indicative of detection of the second traveling wave. The processor is adapted to receive the first signal and the second signal and to determine, based on the first signal and the second signal, where on the transmission line the fault occurred.

Abstract: An apparatus includes at least one Rogowski coil and a processor. The at least one Rogowski coil is positioned within an electrical power distribution network to detect a first traveling wave current caused by a fault on an electrical power transmission line of the network, generate a first signal indicative of detection of the first traveling wave, detect a second traveling wave current caused by the fault on the transmission line, and generate a second signal indicative of detection of the second traveling wave. The processor is adapted to receive the first signal and the second signal and to determine, based on the first signal and the second signal, where on the transmission line the fault occurred.

Abstract: An apparatus includes at least one Rogowski coil and a processor. The at least one Rogowski coil is positioned within an electrical power distribution network to detect a first traveling wave current caused by a fault on an electrical power transmission line of the network, generate a first signal indicative of detection of the first traveling wave, detect a second traveling wave current caused by the fault on the transmission line, and generate a second signal indicative of detection of the second traveling wave. The processor is adapted to receive the first signal and the second signal and to determine, based on the first signal and the second signal, where on the transmission line the fault occurred.

Abstract: Relay devices, systems and methods for obtaining an accurate representation of a current monitored with a Rogowski coil, without integration of the Rogowski coil output voltage signal in the time domain.

Abstract: A Rogowski coil assembly includes a first Rogowski coil that surrounds a conductor and generates a first voltage output signal. A second Rogowski coil also surrounds the conductor. The second Rogowski coil generates a second voltage output signal. A relay device communicates with the first and second Rogowski coils and processes the first and second voltage output signals. For example, the relay device can process the voltage output signals to calculate an amount of noise in the first and second output voltage signals and/or to minimize the amount of noise in the first and second output voltage signals.

Abstract: A differential protection system for power transformers using Rogowski coils as current sensors can support an inrush current detection method based on sensing lows in the derivative of the sensed current. Effective detection of power transformer inrush conditions can enable blocking of a protection relay during inrush where the differential current may exceed a differential threshold value indicative of a fault without the presence of an actual fault. The outputs of the Rogowski coils, being proportional to the first time derivative of the sensed current, may be useful in the inrush detection method. Also, with reduced saturation concerns, the Rogowski coil protection system may employ a single slope response with increased sensitivity. A discrete time sampling technique for identifying low di/dt portions within the sensed current also may be useful in detecting power transformer inrush conditions.

Abstract: Relay devices, systems and methods for obtaining an accurate representation of a current monitored with a Rogowski coil, without integration of the Rogowski coil output voltage signal in the time domain.

Abstract: Relay devices, systems and methods for obtaining an accurate representation of a current monitored with a Rogowski coil, without integration of the Rogowski coil output voltage signal in the time domain.

Abstract: An apparatus includes at least one Rogowski coil and a processor. The at least one Rogowski coil is positioned within an electrical power distribution network to detect a first traveling wave current caused by a fault on an electrical power transmission line of the network, generate a first signal indicative of detection of the first traveling wave, detect a second traveling wave current caused by the fault on the transmission line, and generate a second signal indicative of detection of the second traveling wave. The processor is adapted to receive the first signal and the second signal and to determine, based on the first signal and the second signal, where on the transmission line the fault occurred.

Abstract: A Rogowski coil assembly includes a first Rogowski coil that surrounds a conductor and generates a first voltage output signal. A second Rogowski coil also surrounds the conductor. The second Rogowski coil generates a second voltage output signal. A relay device communicates with the first and second Rogowski coils and processes the first and second voltage output signals. For example, the relay device can process the voltage output signals to calculate an amount of noise in the first and second output voltage signals and/or to minimize the amount of noise in the first and second output voltage signals.

Abstract: Shielded Rogowski coil systems having separate interface cables and methods for eliminating and monitoring noise in signal transmissions over the cables. An embodiment of a Rogowksi coil system includes a first Rogowski coil surrounding a conductor and generating a first voltage output signal, and a second Rogowski coil surrounding the conductor and generating a second voltage signal, wherein the first voltage output signal and the second voltage output signal are processed to address noise components in the output signals. An exemplary method of eliminating and monitoring current with a Rogowski coil includes providing first and second Rogowski coils, connecting an interface conductor to each coil, obtaining distinct voltage outputs from each coil, and applying a noise effect algorithm to the voltage outputs.

Abstract: A differential protection system for power transformers using Rogowski coils as current sensors can support an inrush current detection method based on sensing lows in the derivative of the sensed current. Effective detection of power transformer inrush conditions can enable blocking of a protection relay during inrush where the differential current may exceed a differential threshold value indicative of a fault without the presence of an actual fault. The outputs of the Rogowski coils, being proportional to the first time derivative of the sensed current, may be useful in the inrush detection method. Also, with reduced saturation concerns, the Rogowski coil protection system may employ a single slope response with increased sensitivity. A discrete time sampling technique for identifying low di/dt portions within the sensed current also may be useful in detecting power transformer inrush conditions.

Abstract: A split Rogowski coil assembly having distinct coil loops formed on printed circuit boards that are not joined to one another.

Abstract: An apparatus includes at least one Rogowski coil and a processor. The at least one Rogowski coil is positioned within an electrical power distribution network to detect a first traveling wave current caused by a fault on an electrical power transmission line of the network, generate a first signal indicative of detection of the first traveling wave, detect a second traveling wave current caused by the fault on the transmission line, and generate a second signal indicative of detection of the second traveling wave. The processor is adapted to receive the first signal and the second signal and to determine, based on the first signal and the second signal, where on the transmission line the fault occurred.