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. Interrupter/reclosers after the initial device use a fast close-open event if necessary to arm some switches for proper fault-count opening.

A control system and method for tie point fault interrupter and sectionalizing recloser devices in an electrical grid feeder. The technique enables automated sectionalizing reclosers equipped with three-phase current sensing and single- or three-phase voltage sensing, and able to detect pulse-closing operations, to isolate faults and restore load based on pulse count rather than requiring source re-energization and waiting for loss of voltage timers. The system includes a fault interrupter initiating a pulse-testing sequence upon detecting loss of voltage, where a number of preliminary pulses are used to distinguish transient faults from persistent faults, and pulses are counted by the sectionalizing reclosers to determine which of these devices should open. An alternate configuration is disclosed for reinitializing faults, including the fault interrupter closing if initial pulse testing indicates no fault, and subsequent cycles cause a sectionalizing recloser adjacent the fault to open, allowing the fault interrupter to close and hold.

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.

A control system for and a method of fault isolation and electrical power restoration on an electrical network are provided and comprise: a plurality of electrical power supply facilities connectable to a region of a network, the region comprising a plurality of segments, and each segment being connectable to one or more neighbouring segments by a respective switching device; and the method including the steps of: detecting a fault condition within the region; operating the plurality of switching devices connecting the segments within the region so as to disconnect those segments from one another; performing a reconnection routine for each of a plurality of reconnection zones, being run concurrently.

An electrical installation having a first source of power, such as the utility grid, and a second source of power from an electronic DC-to-AC converter, comprises a smart load center for selecting the source of power independently for each of a number of branch circuits protected by circuit breakers to be the first source or the second source. The smart load center comprises a software-controlled processor for operating the transfer relays that select the first or second source of power for each branch circuit. In the event that a current overload on a branch circuit connected to the DC-to-AC converter causes it to trip before the branch circuit breaker clears the overload, all circuits are transferred to the first power source to trip the fault breaker and then the microprocessor enters a restart sequence to verify that the fault is cleared or else to take other action.

Methods and systems for suppressing arc formation in branch breakers provide a load center that can monitor a branch breaker for indications of arc formation. The load center may include a main breaker that can immediately cut current to the upon receiving an indication of an arc forming in the branch breaker. The indication may be provided by a sensor circuit that sends a trigger signal to the main breaker when arc formation is detected within the branch breaker. The main breaker checks that the trigger signal indicates arc formation, then cuts current to suppress the arc. The main breaker then waits a short period for the branch breaker to clear before restoring current. The wait period is sufficiently short such that devices receiving power from the load center are not adversely affected. To improve cutoff and restoration response times, the main breaker employs a solid-state trip switch.

A method for restoration of a fault isolation in a medium voltage, MV, network having a plurality of feeders and a plurality of normally open, NO, switches possibly in parallel with MV direct current, DC, links is presented. The method is performed in a control device of the MV network. The method includes closing at least two NO switches in parallel with MVDC links of the plurality of NO switches, being connected to a fault isolated feeder of the plurality of feeders of the MV network, and opening the closed at least two NO switches in parallel with MVDC links except one. A control device, a computer program and a computer program product for restoration of a fault isolation in a MV network are also presented.

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.

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.

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.