Abstract: A grounding switch for grounding a high voltage cable in underground switchgear. The switch includes a solid insulation housing and a fixed electrode extending into one end of the housing and being encapsulated in the solid insulation housing. The switch also includes a ground electrode positioned at an opposite end of the housing from the fixed electrode, an air gap formed in the solid insulation housing between the fixed electrode and the ground electrode, and a movable electrode slidable positionable within the air gap to electrically connect and disconnect the fixed electrode to and from the ground electrode. An annular shielding electrode having a ridge is electrically coupled to the fixed electrode proximate the air gap, and shapes an electric field generated by the fixed electrode to be mostly confined within the solid insulation housing.

Abstract: A support bracket assembly for supporting a pair of bushing well interrupter devices provided within a transformer enclosure that encloses a transformer. The support bracket assembly includes a mounting bracket assembly rigidly secured to a parking stand on the enclosure and including a plurality of mounting bosses. The support bracket assembly further includes support brackets, a first adjustable link secured to one of the mounting bosses on the mounting assembly and a mounting boss on a support bracket, a second adjustable link secured to another one of the mounting bosses on the mounting assembly and a mounting bosses on a support bracket, and a third adjustable link secured to mounting bosses on two support bracket, where the first, second and third adjustable links form a triangular configuration.

Abstract: A system and method for determining an open or closed position of a magnetically actuated vacuum interrupter. The method includes applying a voltage signal of a known voltage to the actuator over a predetermined period and determining a change in current over time during the period when the voltage signal is applied to the actuator using an output of a Rogowski coil. The method also includes calculating the inductance using the voltage and the change in current over time at a predetermined time during the period and using the calculated inductance to determine whether the actuator and thus the vacuum interrupter are in the open or closed position.

Abstract: An actuation assembly that is part of and operates to open and close a cut-out mounted switching device. The actuation assembly includes components that cause the switching device to be released from an upper coupling assembly when the actuation assembly opens the switching device and causes the switching device to be closed when the switching device is dropping out of the coupling assembly.

Abstract: A system and method for operating a vacuum interrupter in a self-resetting interrupter. The method includes detecting fault current, opening the vacuum interrupter a first time using power harvested from the current transformer when the fault current is detected, and storing a polarity of the detected fault current when the vacuum interrupter is opened. The method then determines a close time to close the vacuum interrupter so that the current has the same polarity that was stored when the vacuum interrupter was opened and that actuation of closing the vacuum interrupter ends at a current zero crossing, closes the vacuum interrupter at the close time, and opens the vacuum interrupter a second time after the vacuum interrupter is closed using power harvested from the current transformer.

Abstract: A system and method for identifying an earth fault in a resonant grounded medium voltage network that employs a REFCL compensation system. The method derives a zero-sequence real power from a phase voltage to ground on each phase and a current on each phase and aligns the zero-sequence real power in time with a magnitude of a zero-sequence voltage provided by the REFCL compensation system. The method determines when the zero-sequence real power and the zero-sequence voltage exceed predetermined thresholds. The method delays the magnitude of the zero-sequence voltage for a predetermined period of time when the zero-sequence voltage exceeds the threshold and determines that the fault is occurring when both the time aligned zero-sequence real power exceeds the threshold and the magnitude of the zero-sequence voltage exceeds the threshold for the predetermined period of time at the same time.

Abstract: A dropout recloser is capable of in accordance with its operating programming after a predetermined number of fault interrupting operations, e.g., 1, 2, 3 or more but typically 3, to drop out of a cutout and hang freely in a hinge contact of the cutout providing sectionalization with an observable visible gap. The recloser includes fault interrupting and reclosing components, a drop out mechanism and a controller. The drop out mechanism may include a bi-stable actuator to affect fault interrupting operation and dropout operation. The device may include motion limiting structures. The recloser may have a number of operating modes or sequences.

Abstract: A system and method for calibrating a capacitor voltage sensor that measures voltage on a power line coupled through a switch to a primary coil of a transformer. The method includes measuring a control voltage on a secondary coil of the transformer and measuring voltage on the capacitor sensor when the switch is known to be closed. The method identifies a calibration factor that when multiplied by the measured voltage on the capacitor sensor when the switch is closed makes the measured voltage on the capacitor sensor substantially equal to the control voltage. The method subsequently measures voltage on the capacitor sensor when the switch is open or closed during operation of the transformer, and multiplies the subsequently measured voltage on the capacitor sensor when the switch is open or closed by the calibration factor to obtain a measured voltage.

Abstract: A system and method for controlling an operation of devices in a power distribution network. The method determines that there is a power loss in the network as a result of a fault and one or more teams is not receiving power and performs a switching process in switching devices to prevent fault current from flowing to the fault. The method initiates a power restoration process to control the open and closed status of switching devices to isolate the fault and performs the power restoration process by the leader device in a division that the fault is occurring that includes opening and closing switching devices so that power is provided to all of the teams except the team that the fault is in. The method reconfigures the divisions based on which switching devices are now open and selects new leader devices based on the reconfiguration of the divisions.

Abstract: An electrical device including a first cylindrical capacitor, a first terminal electrically coupled to one end of the first capacitor, a first electrical line electrically coupled to the first terminal and a first annular conductive end shield formed over the first terminal and being electrically coupled to the first terminal and the one end of the first capacitor, where the first end shield has a greater diameter than the diameter of the first capacitor. The device also includes a second cylindrical capacitor, a second terminal electrically coupled to one end of the second capacitor, a second electrical line electrically coupled to the second terminal and a second annular conductive end shield formed over the second terminal and being electrically coupled to the second terminal and the one end of the second capacitor, where the second end shield has a greater diameter than the diameter of the second capacitor.

Abstract: A system and method for determining if a fault condition exists in an electrical network. The method includes determining that a fault protection device has been opened and monitoring a voltage angle of a voltage waveform across a vacuum gap switching arrangement if the fault protection device is open, where the vacuum gap switching arrangement includes at least one vacuum gap switching element. The method also includes triggering a breakdown of a vacuum gap in the at least one vacuum gap switching element when the voltage angle corresponds to a predetermined switching angle to enable a temporary current flow through the vacuum gap switching arrangement, measuring the current flow through the vacuum gap switching arrangement, and determining whether the fault condition exists based at least in part on the measured current flow.

Abstract: A switching device for controlling power flow on a power line. The device includes a current sensor for measuring primary current on the line, a first voltage sensor for measuring primary voltage on the line at one side of the switching device, and a second voltage sensor for measuring primary voltage on the line at another side of the switching device. An ADC converts measurement signals from the current sensor and the voltage sensors to digital signals, and a PMU calculates magnitude and phase angle synchrophasor data using the current and voltage measurement digital signals and calibration data.

Abstract: A power restoration system comprising a feeder, a plurality of power sources available to provide power to the feeder, a plurality of normally closed reclosing devices electrically coupled along the feeder, at least one normally open recloser electrically coupled to the feeder, and a plurality of normally closed switches electrically coupled along the feeder between each adjacent pairs of normally closed reclosing devices. Each switch is assigned a position code having a value for each of the plurality of power sources that determines when the switch will open in response to the fault current and which power source the switch is currently receiving power from, where timing control between the reclosing devices and the switches allows the switch to be selectively opened to isolate the fault within a single feeder section between each pair of adjacent switches or between each switch and a reclosing device.

Abstract: A system and method for generating phasors having a phase angle and magnitude from a sinusoidal power signal, and using the phasors to generate a frequency and RoCoF of the power signal. The system and method provide improvements over known systems and methods by correcting the frequency of sensor signals, providing a simplified phasor correction equation, reducing errors in a non-recursive DFT algorithm, improving frequency estimation by spacing out DFTs, correcting the sampling rate, providing linear interpolation of frequency and/or providing a variable DFT window length.

Abstract: A power restoration system for restoring power to feeder segments in response to a fault. The system includes a reclosing device having a switch and one or more sensors for measuring current and/or voltage on the feeder, where the reclosing device performs a pulse testing process to determine circuit fault conditions. The system also includes a plurality of switching devices electrically coupled along the feeder, where each switching device includes a section switch and one or more sensors for measuring current and/or voltage on the at least one feeder. In one embodiment, each switching device recognizes predetermined pulse codes having a sequence of pulses, where the reclosing device uses the pulse testing process to generate and selectively transmit defined pulse codes on the feeder that selectively cause the section switches to change states between an open state and a closed state depending on the code.

Abstract: A transformer assembly including a transformer that is part of an underground residential power distribution circuit and that provides fault isolation and restoration. The transformer assembly includes an enclosure enclosing a primary winding and a secondary winding. The transformer assembly also includes first and second switching devices mounted to a panel of the enclosure, where each switching device includes an outer housing, a transformer interface electrically coupled to the primary winding, a connector interface electrically coupled to a first connector and a vacuum interrupter having a fixed contact and a movable contact. The fixed contact is electrically coupled to the connector interface or the transformer interface and the movable terminal is electrically coupled to the other connector interface or the transformer interface.

Abstract: A system and method for allowing islanding in an underground power distribution network when power is lost to the network. The network includes transformers having source side and load side switching devices and servicing a transformer section. The method includes detecting loss of voltage to the network, opening the source side and the load side switching devices in all of the transformers and allowing distributed power generation sources in the sections serviced by the transformers to provide power to the section. The method also includes closing one or both of the source side switching device and the load side switching device of a transformer that services a section that has power generation sources providing excess power, and closing a source side switching device or a load side switching device in an adjacent transformer to the transformer section providing excess power to provide power to the adjacent section.

Abstract: A center post assembly for eliminating sagging of a roof panel in a cabinet, where doors of the cabinet latch to the post assembly. The post assembly includes a base portion and a post portion, where one of the base portion or the post portion includes a plurality of slots and the other one of the base portion or the slot portion includes a plurality of threaded studs. The base portion further includes a first bracket and a jackscrew threaded into a threaded opening in the first bracket and the post portion further includes a second bracket, where the jackscrew engages the second bracket so that rotation of the jackscrew causes the second bracket to move relative to the first bracket so that the studs slide in the slots and increase the length of the post assembly to remove the sag.

Abstract: A current transformer assembly for harvesting power from a primary conductor, such as a power line, for operating electronics, where the assembly is secured to the conductor while the conductor is connected. The assembly includes a current transformer having a transformer structure with a central opening that accepts the primary conductor and a spindle member for accepting a current transformer magnetic tape operating as the core of the current transformer. The assembly also includes a tape carrier secured to the structure on which the transformer tape is wound, and a winding device operable to unwind the transformer tape from the tape carrier and wind the tape onto the spindle member.

Abstract: A switch assembly including a switch and an interface physically coupled to the switch and configured to be physically coupled to an electrical component, such as a transformer. The switch assembly also includes an interface having electrical hardware electrically coupled to the switch and configured to be electrically coupled to the component. The switch assembly further includes a surge arrester having an insulation member, a grounding jacket formed over a portion of the insulation member and a conductor extending through the insulation member and being electrically coupled to the hardware and the grounding jacket. The interface further includes a releasable connector that is electrically coupled to the conductor and allows the surge arrester to be disconnected from the interface.