Abstract: Switchgear including a sealed tank enclosing electrical components and being filled with a dielectric gas containing CO2. The tank also encloses an activated alumina desiccant that absorbs a limited amount of the CO2. In one non-limiting embodiment, the dielectric gas is a blended CO2—Novec™ 4710 dielectric gas and the activated alumina is in the form of beads enclosed in a bag.

Abstract: A system and method for adaptive impedance protection in a power network. The method includes determining a measured impedance in an upstream interrupting device, determining an impedance set point in the upstream interrupting device, and identifying a predetermined percentage of the impedance set point. The method also includes determining if the measured impedance falls below the predetermined percentage, determining whether a change in a measured current value on the power line is less than a threshold change value in a downstream interrupting device, and sending the determination of whether the change in the measured current value is less than the threshold change value from the downstream interrupting device to the upstream interrupting device. The upstream interrupting device is opened if the measured impedance falls below the predetermined percentage of the impedance set point and the change in the measured current value is less than the threshold change value.

Abstract: A vacuum interrupter including a nominally cylindrical insulator having a first insulator portion and a second insulator portion defining a gap therebetween and a nominally cylindrical vapor shield having a first ring of a plurality of spaced apart bobbles and a second ring of a plurality of spaced apart bobbles. A gap ring including a series of spaced apart cut-out notches facing the vapor shield is positioned within the gap. The plurality of bobbles in the first and second ring of bobbles are configured so that the bobbles in the second ring pass through the cut-out notches in the gap ring and the bobbles in the first ring rest on the gap ring.

Abstract: An underground power distribution network that clears faults using detected traveling waves. The network includes a power source, a feeder receiving power from the power source, and a plurality of series connected switchgear disposed along the feeder. Each switchgear includes at least one current interrupting device for interrupting current on the feeder, at least one current sensor for measuring current on the feeder, and a controller responsive to current measurement signals from the current sensor. A communications link provides communications between the controllers. The current sensors detect traveling waves as a result of a fault on the feeder and the controllers broadcast messages on the communications link identifying whether the controller receives positive polarity or negative polarity traveling waves that identify whether the fault is downstream or upstream of the switchgear so as to determine which current interrupting device will be opened to clear the fault.

Abstract: A system and method for determining when an electronic interrupting device will open in response to detecting overcurrent, where the interrupting device protects a transformer in a power distribution network. The method includes obtaining a time/current through fault protection curve that is defined by a plurality of time/current points for the transformer that identifies when the transformer may experience thermal or mechanical damage in response to a certain current flow over a certain time in the transformer windings, selecting a time multiplier, and determining an operating curve for the interrupting device by multiplying the multiplier and a time portion of each of the plurality of time/current points on the through fault protection curve, where the operating curve identifies when the interrupting device will open in response to a certain current flow over a certain time.

Abstract: A switch assembly including a vacuum interrupter having a fixed contact and a movable contact, an actuator operable to move the movable contact, and a drive rod assembly coupled to the movable contact and the actuator. The drive rod assembly includes a male part and a female part where the male part is inserted into and coupled to the female part. One of the male part or the female part includes a conductor that provides an electrical connection between the male and female parts and one of the male part or the female part includes a locking ring that snap fits into a groove in the other male or female part.

Abstract: A method for preventing unintentional islanding of loop networks when a distributed power source is providing power to the network when network power is lost. The method includes detecting loss of voltage to the network, opening the source side switching device in the transformers nearest both ends of the power line, and detecting that voltage has been restored to the network. Also provided are a system and method for preventing distributed power generation export in a power distribution network during normal operation. The method includes determining the apparent power at the source side of each of the transformers, determining the apparent power at the load side of each of the transformers, comparing the determined apparent powers, and opening the source side and load side switching devices in any transformer where the determined apparent powers are not the same.

Abstract: A method for determining an optimized TCC operating curve for an electronic interrupting device that protects a distribution transformer in a power distribution network, where the TCC operating curve is some optimized predetermined percentage above a TCC curve for normal transformer operation. The method includes providing a TCC transformer curve that identifies an allowed transformer operation current once the transformer magnetics have been stabilized and the transformer is operating normally, and determining a TCC operating curve that is defined by points along the transformer curve plus a predetermined percentage above the transformer curve, where the operating curve identifies a response time for when the electronic interrupting device will open in response to a certain current flow.

Abstract: A switch assembly including an actuator assembly operable to magnetically latch a switch in a closed position, where the actuator assembly includes a cup member coupled to the drive rod opposite to the switch and an opening spring positioned within the cup member and being held in compression when the switch is latched closed, and where the cup member includes a central opening. The switch assembly further includes a scissor link having a first leg and a second leg pivotally attached at a pivot point, where one end of the first and second legs extend into the central opening and are rigidly attached to the cup member and an opposite end of the first and second legs extend through the cover, and where pulling the link away from the actuator assembly breaks the magnetic latch and opens the switch.

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 method for preventing unintentional islanding of loop networks when a distributed power source is providing power to the network when network power is lost. The method includes detecting loss of voltage to the network, opening the source side switching device in the transformers nearest both ends of the power line, and detecting that voltage has been restored to the network. Also provided are a system and method for preventing distributed power generation export in a power distribution network during normal operation. The method includes determining the apparent power at the source side of each of the transformers, determining the apparent power at the load side of each of the transformers, comparing the determined apparent powers, and opening the source side and load side switching devices in any transformer where the determined apparent powers are not the same.

Abstract: A device having a pulse catching function for detecting fault test pulses in an electrical power distribution network in response to a fault. The device includes one or more sensors for measuring current and/or voltage, where the device detects the pulses by loss of voltage followed by identifying one or more of a peak current magnitude of the pulses being greater than a predetermined current value, a pulse duration of the pulses being greater than a predetermined time, a predetermined interval between consecutive pulses and a presence of a pulse/inverse pulse sequence.

Abstract: A system and method for point on wave closing of a switching device, where the close initiation point is selected so that a minor current loop is generated that minimizes the accumulated current during the closing operation. The method includes determining bounce characteristic of contacts in the switching device during the closing operation, identifying available close initiation points on a voltage wave for a voltage across the contacts, selecting one or two of the close initiation points on the voltage wave that minimizes the accumulation of current during the closing operation, and closing the switching device using the selected close initiation point.

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 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 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 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.