Abstract: A system and method for providing fault isolation in a power distribution network. The network includes a power line, a recloser coupled to the power line and a plurality of switching devices coupled to the power line downstream of the recloser, where each switching device is capable of detecting fault current in response to the fault and detecting presence of voltage. In one non-limiting embodiment, the method includes detecting overcurrent, loss of voltage and return of voltage by the switching devices and includes sequentially opening and closing switching devices from the recloser to a switching device immediately upstream of the fault in response to detecting overcurrent, loss of voltage and return of voltage.

Abstract: A system and method for isolating a fault in a power distribution network. The network includes a power line, a plurality of transformers electrically coupled to and positioned along the power line, and a recloser coupled to the power line. Each transformer has a unique address identifying the transformer and includes a source side switching device at an upstream side of the transformer and a load side switching device at a downstream side of the transformer. The method includes learning the address by each transformer of its immediate neighbor transformers, detecting overcurrent by some of the switching devices as a result of the fault, detecting loss of voltage by some of the switching devices and sending clear to close messages to selectively open and close certain ones of the switching devices using the transformer addresses to limit the number of switching devices that are operated and to isolate the fault.

Abstract: A switch assembly that includes a cutout mounted fault interrupting switching device and ice shields that block ice build-up on the assembly that may otherwise impede a dropout operation of the switching device. The switching device includes a switch, an upper electrical contact and a lower electrical contact. The switch assembly includes an upper coupling assembly configured to releasably engage the upper electrical contact and a lower coupling assembly configured to engage the lower electrical contact in a pivoting engagement, where the switching device is operable to pivot relative to the lower coupling assembly when the upper electrical contact is released from the upper coupling assembly. The switch assembly further includes an upper ice shield coupled to and formed over the upper coupling assembly and a lower ice shield coupled to and formed over the lower coupling assembly.

Abstract: A series Z-source circuit breaker including a semiconductor switch that breaks source power being provided to a load in response to overcurrent. An electromechanical switch is electrically coupled in parallel with the semiconductor switch, a first capacitor is electrically coupled to an output side of the semiconductor switch, a second capacitor is electrically coupled in parallel with the semiconductor switch, and a delay circuit is electrically coupled in series with the first capacitor. The semiconductor switch is in an open position and the electromechanical switch is in a closed position when overcurrent is not present. Upon detection of overcurrent the semiconductor switch is closed, the electromechanical switch is opened and the delay circuit is controlled to delay when reverse bias current is provided from the first capacitor to the semiconductor switch to prevent source power from being provided to the load to give the electromechanical switch time to open.

Abstract: An electrical power network employing fault location, isolation and system restoration. The system includes a plurality of switching devices electrically coupled along a power line downstream of a fault interrupting device. The switching devices each have current and voltage sensing capability and the capability to provide pulse tests for detecting fault presence. The fault interrupting device performs reclosing operations, and when the plurality of switching devices detect fault presence a predetermined number of times in coordination with reclosing operations performed by the fault interrupting device and detect loss of voltage, each switching device opens. The fault interrupting device closes when the switching devices open, and the switching devices sequentially pulse test and close from a furthest upstream switching device when detecting return of voltage and no fault presence until a switching device closest to the fault pulse tests and detects fault presence and locks open.

Abstract: A system and method for providing fault protection and coordination between fault interrupting devices in a power distribution network. The method includes assigning a coordination number to each device depending on where the device is in the network and what other fault interrupting devices are downstream of the device, where the assigned coordination number to the device is equal to the largest coordination number of any downstream device plus one. The method further includes calculating a TCC curve for the devices having the lowest coordination number based on a TCC curve of a fuse-like device downstream of the device and tolerances of the device. The method then sequentially calculates a TCC curve for the devices having the next lowest coordination number based on the TCC curves of the devices having a lower coordination number and tolerances of the device until all of the devices have a TCC curve.

Abstract: An energy harvesting circuit for harvesting energy from a medium voltage power line. The energy harvesting circuit includes an input capacitor electrically coupled to the power line and storing power therefrom, and a flyback converter including a primary coil and a secondary coil. The harvesting circuit further includes a switching circuit electrically coupled in series with the primary coil and being operable to electrically connect and disconnect the input capacitor to and from the primary coil, where the switching circuit includes an input voltage regulation feedback circuit for regulating an input voltage provided to the switching circuit from the input capacitor. The harvesting circuit also includes an output capacitor electrically coupled to the secondary coil and the actuator, where the output capacitor is charged by the secondary coil when the switching circuit is closed to provide power to an actuator to close a vacuum interrupter.

Abstract: A method for identifying a location of a fault in an electrical power distribution network that includes identifying an impedance of an electrical line between each pair of adjacent utility poles, measuring a voltage and a current of the power signal at a switching device during the fault, and estimating a voltage at each of the utility poles downstream of the switching device using the impedance of the electrical line between the utility poles and the measured voltage and current during the fault. The method calculates a reactive power value at each of the utility poles using the estimated voltages, where calculating a reactive power value includes compensating for distributed loads along the electrical line that consume reactive power during the fault, and determines the location of the fault based on where the reactive power goes to zero along the electrical line.

Abstract: A system and method for estimating fault current using a sliding observation window that is shorter than one cycle. The method may also include providing a pickup level that defines a current threshold for opening a switch in response to detecting the fault current; estimating the fault current from current measurement signals; accumulating time from a reset zero position during the time that the estimation of the fault current is greater than the pickup level; subtracting time from the accumulated time during the time that the estimation of the fault current is less than the pickup level after time has been accumulated from when the estimation of the fault current is greater than the pickup level; detecting the fault current if the accumulated time reaches a predetermined accumulation time; and opening the switch if the fault current is detected.

Abstract: An actuator assembly including a first actuator having a first magnetically actuated plunger and a first latching plate, where the first plunger is operable to be magnetically latched to the first latching plate. The actuator assembly further includes a second actuator coupled to and axially aligned with the first actuator. The second actuator includes a second magnetically actuated plunger, a second latching plate, a sleeve positioned within and extending from the second plunger and being rigidly secured to the first plunger, and a tolerance spring wrapped around the sleeve. The second plunger is operable to be magnetically latched to the second latching plate, where latching of the second plunger causes the tolerance spring to compress and provide additional latching force of the first plunger to the first latching plate.

Abstract: A triggered vacuum gap (TVG) device that has application as a closing switch for synchronized closing in distribution and transmission power systems. The TVG device controllably sustains a current arc in the device through initial current zeros created by power system transients and, thereby, prevents premature interruption of the closing operation. The TVG device includes main electrodes defining a vacuum gap therebetween and a triggering electrode providing a triggering gap between one main electrode and the triggering electrode. The TVG device also includes a triggering circuit having a high voltage impulse source that supplies a fast rising impulse voltage to the one main electrode and the triggering electrode for creation of a plasma to provide an initial breakdown of the triggering gap and a low voltage unidirectional current source that supplies current to the one main electrode and the triggering electrode once the first triggering gap breakdown has occurred.

Abstract: An insulator that has particular application for enclosing a switching device, such as a vacuum interrupter. The insulator includes a body having a top portion and a bottom portion, and a plurality of ring-shaped sheds extending from the body between the top portion and the bottom portion. The sheds are asymmetrical in an axial direction such that an axial dimension of the sheds at one side towards the front of the switching device is shorter than an axial dimension of the sheds at an opposite side towards the rear of the switching device. The axial dimension of the sheds uniformly increases from the one side to the opposite side.

Abstract: A vacuum interrupter including a vacuum bottle, a fixed contact extending through one end of the vacuum bottle and a movable contact positioned within the vacuum bottle relative to the fixed contact so that a gap is defined between the fixed contact and the movable contact when the vacuum interrupter is open and the fixed contact and the movable contact are in contact with each other when the vacuum interrupter is closed. An insulated drive rod is rigidly coupled to the movable contact opposite to the fixed contact and a circular flexible conductor is coupled to the movable contact and flexes when the movable contact is moved by the drive rod. The flexible conductor can be, for example, a laminate structure including a plurality of stacked conductive laminates each having a plurality of spirals separated by gaps or a linear spring trampoline conductor.

Abstract: Switchgear with an insulated enclosure with interconnection bushings secured to an exterior of the enclosure to provide an electrical connection from conductors to components disposed within the enclosure. A mounting stand is provided that is adapted to be secured to a pad. Existing electrical conductors extend from the pad. The mounting stand includes mounting members. The enclosure includes mounting points. The mounting members are formed with a plurality of mounting locations, and the mounting points are aligned to a mounting location such that the bushings are sufficiently aligned with the conductors to allow interconnection using standard connectors.

Abstract: A method for identifying a location of a fault in an electrical power distribution network that includes identifying an impedance of an electrical line between each pair of adjacent utility poles, measuring a voltage and a current of the power signal at a switching device during the fault, and estimating a voltage at each of the utility poles downstream of the switching device using the impedance of the electrical line between the utility poles and the measured voltage and current during the fault. The method calculates a reactive power value at each of the utility poles using the estimated voltages, where calculating a reactive power value includes compensating for distributed loads along the electrical line that consume reactive power during the fault, and determines the location of the fault based on where the reactive power goes to zero along the electrical line.

Abstract: A system and method for determining a squelch level for each transformer in a series of transformers connected to a power line that communicate with each other through PLC. The method includes selectively transmitting a PLC test message by each transformer on the power line both upstream and downstream of the transmitting transformer to determine that the transmitting transformer can communicate with other transformers; responding to the PLC test message that is received by each transformer to identify the transformers that can communicate with the transmitting transformer; measuring the RSSI of the PLC messages that each transformer receives; recording the strongest RSSI in each transformer of the PLC messages that are received by the transformer; and setting the squelch level for each transformer as a predetermined reduction of the recorded RSSI in each transformer.

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 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: 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.