A method for controlling a power distribution network includes receiving, by an electronic processor, a fault indication associated with a fault in the power distribution network from a first isolation device of a plurality of isolation devices. The processor identifies a first subset of a plurality of phases associated with the fault indication and a second subset of the plurality of phases not associated with the fault indication. The first and second subsets each include at least one member. The processor identifies an upstream isolation device upstream of the fault. The processor identifies a downstream isolation device downstream of the fault. The processor sends an open command to the downstream isolation device for each phase in the first subset. Responsive to the first isolation device not being the upstream isolation device, the processor sends a close command to the first isolation device for each phase in the first subset.

A system for controlling a power distribution network providing power using a plurality of phases comprises an electronic processor and memory storing instructions that, when executed by the electronic processor, cause the system to receive a loss of voltage fault indication associated with a fault in the power distribution network. The electronic processor identifies a first subset of the plurality of phases associated with the loss of voltage fault indication and a second subset of the plurality of phases not associated with the loss of voltage fault indication. The first and second subsets each include at least one member. The electronic processor identifies a downstream isolation device downstream of the fault. The electronic processor sends an open command to the downstream isolation device for each phase in the first subset. The electronic processor sends a close command to a tie-in isolation device downstream of the downstream isolation device.

A system for controlling a power distribution network providing power using a plurality of phases comprises an electronic processor and memory storing instructions that, when executed by the electronic processor, cause the system to receive a loss of voltage fault indication associated with a fault in the power distribution network. The electronic processor identifies a first subset of the plurality of phases associated with the loss of voltage fault indication and a second subset of the plurality of phases not associated with the loss of voltage fault indication. The first and second subsets each include at least one member. The electronic processor identifies a downstream isolation device downstream of the fault. The electronic processor sends an open command to the downstream isolation device for each phase in the first subset. The electronic processor sends a close command to a tie-in isolation device downstream of the downstream isolation device.

A method of protection can be used in response to a fault in a multi-terminal power transmission system that includes a first transmission line section connecting a first terminal to a transmission line junction, a second transmission line section connecting a second terminal to the transmission line junction and a third transmission line section connecting a third terminal to the transmission line junction. The fault being located in one of the first, second or third transmission line sections. The section having the fault can be determined based on a number of calculations and other factors and a switching device can be controlled according to the identification of the section having the fault.

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 sectionalizing switches and a source interrupter/recloser in a feeder, or portion of the distribution grid, which enables fault location, isolation and service restoration without requiring a communications infrastructure and communications equipment at the switches. The method includes each switch adaptively configuring fault-count, load-count and voltage-count thresholds upon which the switch should open. The thresholds for each switch are based on the switch's proximity to the active feeder source, which requires a determination of which source is powering the feeder at a particular time. Five different methods are disclosed to determine which source is active. When a fault is detected, the source interrupter/recloser opens and then begins a pulse testing or reclosing sequence, where the switches open to isolate the fault when reaching their fault-count or voltage-count threshold. When the fault is isolated, the source recloses to restore power to unaffected portions of the feeder.

Even when one power conversion device among a plurality of power conversion devices connected in parallel experiences a short circuit, the other power conversion devices having experienced no short circuit can be promptly restarted. Each power conversion device includes: a short circuit occurrence determination unit configured to determine, on the basis of a current value at an output terminal, whether or not a short circuit has occurred; a short circuit elimination determination unit configured to determine, on the basis of a current value and a voltage value at the output terminal, whether or not the short circuit has been eliminated; and a current interruption unit configured to, on the basis of determination by the short circuit occurrence determination unit and determination by the short circuit elimination determination unit, interrupt current that flows from a power conversion unit to the output terminal or cancel the interruption.

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.

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.

Disclosed are a self-power relay and a method for preventing a malfunction thereof. The self-power relay comprises: a self-power generation unit for autonomously generating a driving power by performing conversion into a preconfigured driving power level by using, as a source power, a system power of a transmission/distribution line or power system; and a relay operation unit, for measuring the amount of a system power of a transmission/distribution line or power system, blocking a system power transmitted to a load when a failure occurs, and monitoring a change in a source power of the self-power generation unit in real time, so as to stop a relay operation of the self-power generation unit and a relay operation of the relay operation unit itself when abnormality occurs, wherein a malfunction can be prevented by checking an unstable state of a source current and voltage for generation of a self driving power.