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 capacitive voltage sensor that has particular application to be molded into an insulating body of a switch. The voltage sensor includes an annular electrode assembly having a grounded electrode including an inner ring and an outer ring defining a space therebetween, and a sensing electrode positioned in the space and being substantially surrounded by the inner and outer rings. The body is formed around the electrode assembly and a cylindrical center conductor extends through the electrode assembly. Capacitive coupling is provided between the sensing electrode and the center conductor by one or more openings in the inner ring, such as a single round hole, a slot or a plurality of symmetrically disposed round holes or slots. The inner and outer rings can be attached at one end so that the grounded electrode is a single piece or the rings can be separate rings electrically coupled together by conductive screws.

Abstract: A communication-based permissive protection method for protecting an electrical power distribution network from a fault. The network includes a power source, an electrical line and a plurality of fault interrupters, where the fault interrupters are operable to prevent current flow in response to the fault. The method includes detecting the fault by each fault interrupter that is between the fault and the power source, and sending a drop of voltage message from each fault interrupter that doesn't detect the fault, but does detect a drop of voltage as a result of the fault to its immediate upstream fault interrupter. The method opens the fault interrupter that both detects the fault and receives a drop of voltage message from all of the fault interrupters immediately downstream of that fault interrupter.

Abstract: A method for fault location and isolation in a power distribution network, where the network includes a plurality of switching devices provided along a feeder, and at least one of the switching devices does not have voltage sensing capabilities. The method includes detecting an overcurrent event in the network from the fault and interrupting the overcurrent event by opening and then immediately locking out or subsequently reclosing and testing the fault. A count value is increased in each switching device that detected the overcurrent event. A message is sent from each of the switching devices that detected the overcurrent event and then detected the loss of voltage upstream to an upstream neighbor switching device. Current measurements in the messages, measured current by the devices and the counts values in the devices determine what devices are opened to isolate the fault.

Abstract: A system and method for quickly detecting fault current on a power line in an electrical power distribution network. A switch assembly includes a detecting circuit for quickly detecting the fault current on the power line. The circuit includes a Rogowski coil wrapped around the power line that provides an output measurement signal that is proportional to a change in the current flow on the line, and a passive integrator responsive to the output measurement signal from the Rogowski coil that integrates the output measurement signal over time. The circuit also includes an amplifier responsive to and amplifying the integrated output measurement signal and a microcontroller responsive to the amplified output measurement signal that calculates the current flow on the line using the amplified output measurement signal. A current transformer harvests energy from the power line to power the circuit when the fault current is occurring.

Abstract: A system and method for fault location and isolation in an electrical power distribution network, where the network includes a plurality of switching devices provided along a feeder. The method includes detecting an overcurrent event in the network from the fault and interrupting the overcurrent event by opening and then immediately locking out or subsequently reclosing and testing the fault. A count value is increased in each switching device that detected the overcurrent event. A count and current (C&I) message is sent from each of the switching devices that detected the overcurrent event and then detected the loss of voltage upstream to an upstream neighbor switching device. Current measurements in the C&I messages, measured current by the devices and the counts values in the devices determine what devices are opened to isolate the fault.

Abstract: A switch assembly including a switch and a high impedance element used for energy harvesting purposes that are connected to a power line at one end and assembly electronics at an opposite end, where in one non-limiting embodiment the switch assembly has particular application for use in connection with a vacuum interrupter. The high impedance element has higher impedance than the switch so that current flows through the switch from the power line when the switch is closed and through the high impedance element from the power line when the switch is open, where power from the high impedance element can power a switch closing device, such as a solenoid actuator. The high impedance element can be a resistive element, a capacitive element or a combination of a resistive and capacitive element.

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 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 fault detection system that includes a recloser configured to perform a reclosing operation in response to detecting overcurrent, where the recloser includes a communications device for receiving communications signals. The system also includes a transformer having an outer can, a sensor mounted to the can and extending into the can for measuring pressure therein, where the sensor includes a mechanical indicator that extends when overpressure is detected. The transformer further includes a radio mounted to the can and coupled to the sensor, where the radio includes a switch coupled to the mechanical indicator and a transmitter. When the mechanical indicator extends in response to detecting overpressure in the can it causes the switch to close which causes the transmitter to send a signal that is received by the communications device, which prevents the recloser from reclosing.

Abstract: A fault detection system that that prevents a recloser from reclosing if a fault is determined to be internal to a transformer, where the recloser is configured to perform a reclosing operation in response to detecting overcurrent. The recloser includes a sensor, such as a light sensor, directed towards the transformer and detecting a fault event. If the recloser detects overcurrent, but the sensor does not detect the fault event, it is assumed that the fault is internal to the transformer and the recloser is prevented from reclosing.

Abstract: A method for performing a low energy pulse testing in a power distribution network that causes contacts to close and then open in about one fundamental frequency cycle of current flow time and close on a voltage waveform that produces symmetrical fault current. The method includes energizing a magnetic actuator to move the actuator against the bias of a spring to move a movable contact towards a fixed contact. The method also includes de-energizing the actuator when the movable contact makes contact with the fixed contact so as to allow the spring to move the movable contact away from the fixed contact so that the amount of time that the current conducts is about one fundamental frequency cycle of the current, where energizing the magnetic actuator occurs when an applied voltage on the switch assembly is at a peak of the voltage wave so that the current is symmetric.

Abstract: A control system and method for sectionalizing switches and pulse-testing interrupter/reclosers in a distribution grid feeder which enables fault location, isolation and service restoration without requiring an external communications infrastructure to pass information between the switches. The method includes switches entering an armed state when they experience a high fault current during an initial fault event. Then, when the interrupter/recloser runs its test pulse sequence, any armed switch counts all test pulses as fault pulses, while non-armed switches count the test pulses as load pulses. Switches open to isolate the fault based on threshold values of fault pulse count and load pulse count. When an initially active interrupter/recloser completes its test pulse sequence, another interrupter/recloser begins its sequence, and all switches reconfigure their threshold values based on the new interrupter/recloser.

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 fault protection system for providing protection from fault current for components and devices on a lateral line proximate to a distribution transformer in a power distribution network. The system includes a single-phase recloser having a vacuum interrupter that is controlled by a controller. In one embodiment, the recloser has an insulating body that is molded in combination with an insulating body of a bushing that is connected to the distribution transformer. In this embodiment, the controller can be powered by a current transformer within the recloser. In another embodiment, the recloser is mounted to a utility pole separate from the distribution transformer, where the controller is powered by the low voltage side of the transformer and the current transformer is eliminated. An isolated power supply is provided between the transformer and the controller to provide voltage isolation.

Abstract: A system and method for restoring power in a power distribution network. The network includes at least two power sources, at least one feeder and a plurality of switching devices positioned along the at least one feeder and being in communications with each other. The method determines that one or more of network sections is not receiving power, and determining a plurality of possible power restoration solutions that identify what sections each of the power sources that are available to provide power can provide power to based on a power capacity of the sources and a load requirement of the sections. The method applies predetermined selection criteria to the plurality of possible solutions to determine which of the possible solutions will be used as an actual solution, and selectively switches the switching devices between open and closed states to apply the actual solution.

Abstract: A switch assembly including a switch and a high impedance element used for energy harvesting purposes that are connected to a power line and assembly electronics. The high impedance element has higher impedance than the switch so that current flows through the switch from the power line when the switch is closed and through the high impedance element from the power line when the switch is open. The switch assembly also includes a current sensing device, such as a current sensing resistor, electrically coupled in series with the high impedance element and the electronics. By measuring the current flow using the current sensing device, it is possible to infer the voltage across the high impedance element since its impedance is known. This voltage can be used to provide point on wave closing of the switch and to determine the line voltage magnitude.

Abstract: A system and method for restoring power in a closed-loop power distribution network. The network includes at least two power sources, at least one feeder and a plurality of switching devices positioned along the at least one feeder and being in communications with each other. The method performs a radial restoration process for restoring power and then determines that at least one of the sections is not receiving power after the radial restoration process has been performed. The method estimates power flow through each switching device and determines an available power capacity from each switching device. The method then determines if the unpowered sections can be powered by any of their neighbor and non-neighbor devices. The method virtually closes the switching devices to power the unpowered sections and updates the estimation of power flow through each switching device and determination of available power capacity from each switching device.

Abstract: A duct assembly for covering electrical connections between electrical equipment enclosures having a gap therebetween. The duct assembly includes a first frame configured to be mounted to one of the enclosures, where the first frame includes a flange mounted to the enclosure and a flange to which a gasket is secured that extends all of the way around the first frame. The duct assembly also includes a second frame configured to be mounted to the other enclosure, where the second frame includes a flange mounted to the enclosure and a flange to which a gasket is secured that extends all of the way around the second frame. The duct assembly further includes a duct that compresses and is coupled only to the gaskets that enclose each end of the gap.

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.