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 guiding pull ring member for guiding a unit top contact in a switch assembly into a mounting contact. The guide ring member includes a mounting ring defined in a first plane, a grasping ring coupled to one side of the mounting ring and being defined in a second plane perpendicular to the first plane, and a V-shaped guide piece coupled to the mounting ring at a side opposite from the grasping ring and extending perpendicular to the first plane. The guiding pull ring member has particular application for a solenoid operated vacuum interrupter recloser switch mounted to a utility pole.

Abstract: A snap-in link that provides a snap-in connection between two devices. The link includes an elongated portion and first and second flexible arms coupled to the elongated portion at one end and having a first snap-in slot at an opposite end. The flexible arms include an outer side, an inner side, a plurality of stress-concentration indentations formed in the outer side and a plurality of stress-concentration indentations formed in the inner side, where a nub is formed in each of the indentations along the outer side and the flexible arms define a slot therebetween.

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: 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 system and method for determining the optimal time to perform a pulse test to determine the presence of a fault after a switch opens to clear the fault to prevent generator instability. The method includes detecting the fault, opening a switch to clear the fault, determining an optimal time for performing the pulse test for determining the continued presence of the fault based on predetermined system data and parameters after the switch is opened so as to prevent the pulse test from occurring too early that could cause generator instability, and performing the pulse test at the optimal time to determine if the fault is still present. Determining the optimal time can use available system data and information, such as a priori knowledge or real-time behaviour. If the fault is not present, then the method determines a desired time to perform a reclose operation.

Abstract: Described are curve shapes that may be implemented in a transformer protector that provide enhanced fault protection. A transformer protector curve rating structure relates response curves to the transformer size and simplifies selection of response curves implemented within a transformer protector and associated transformer.

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 control system and method for a group of interconnected feeders which enables fault location, isolation and service restoration without requiring each switch to have topology knowledge of devices in adjacent feeders. The method defines, for each switch, connectivity and X/Y directional information about its neighboring switches and propagates this information throughout each feeder. A leader device is also determined for each feeder. Information about topology of adjacent feeders is not needed by all devices. Only normally-open tie switches which define a boundary between two adjacent feeders have knowledge of the devices in both feeders. Switches which open during fault isolation automatically find open tie switches in a direction opposite the fault, and request service restoration downstream of the fault by providing power from an adjacent feeder. Leader devices ensure an overload condition is not created before initiating opening and closing operations of switches downstream of the fault.

Abstract: A reclosing fault protection device detects a partial bypass state. Upon detecting the partial bypass state, the fault protection device implements a ground trip delay operating state. The ground trip delay operating state provides a delayed ground trip response characteristic.

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 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 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 transformer fault detection, where the transformer includes a primary winding coupled to a medium voltage power line and a secondary winding providing a stepped down voltage of the medium voltage. The detection system includes a switching device, where the switching device includes a first voltage measuring device for measuring the voltage on the primary winding, a controller for processing measured voltages and a transceiver for receiving and transmitting messages. The detection system also includes a second voltage measuring device for measuring the stepped down voltage on the secondary winding, where the second voltage measuring device includes a transmitter for transmitting the measured step down voltage to the switching device. The controller uses the measured voltages to calculate a transformer turns ratio (TTR) of the transformer to determine whether a transformer fault.

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 maintaining electrical stability of a high-voltage transmission power system in response to a fault. The method includes detecting the fault, opening a switch to clear the fault, performing a first pulse test for a predetermined duration of time to determine if the fault is still present, preventing a reclosing operation from occurring if the pulse test indicates that the fault is still present, and allowing the reclosing operation to occur if the first pulse test indicates that the fault is not present. One or more subsequent pulse tests can be performed if the first pulse test is inclusive about the persistence of the fault, where the reclosing operation is prevented from occurring if the pulse tests indicate that the fault is still present and the reclosing operation is allowed if the pulse tests indicate that the fault is no longer present.

Abstract: A switch assembly that is part of a transformer in an underground residential power distribution circuit and that provides fault isolation and restoration. The switch assembly includes first and second switching devices each having an outer housing, a transformer interface electrically coupled to the transformer, a connector interface electrically coupled to a first connector and a first vacuum interrupter having a fixed contact and a movable contact, where the fixed contact is electrically coupled to the connector interface and the movable contact is electrically coupled to the transformer interface. A control board controls the first and second switching devices, where the control board is responsive to voltage signals from capacitors in the first and second switching devices.

Abstract: A switching device that is part of a transformer in an underground residential power distribution circuit and provides fault isolation and restoration. The switching device includes a transformer interface for coupling the device to the transformer and a connector interface for coupling the device to a connector. The device also includes a vacuum interrupter having a fixed terminal and a movable terminal, where the fixed terminal is electrically coupled to the connector interface and the movable terminal is electrically coupled to the transformer interface. A control rod is coupled to the movable terminal, an actuator assembly is coupled to the control rod and is operable to move the control rod to open and close the vacuum interrupter. A capacitor is electrically coupled to the fixed terminal, and provides an interface for power line communications signals, voltage sensing, help determine power flow direction and help determine the distance to a fault.

Abstract: A mounting bracket for securing a control unit that controls a bushing well interrupter device provided within a transformer enclosure associated with an underground loop circuit. The mounting bracket includes a support portion configured to hold the control unit and a mounting portion coupled to the mounting portion, where the mounting portion including a hook portion configured to hook onto one terminal in the enclosure and a notch portion configured to rest against another terminal in the enclosure.

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.