A method of clearing a fault in a high voltage DC electrical network, including power converters interconnected by a DC power transmission, comprising: detecting a fault in the DC power transmission and reconfiguring each power converter to a fault blocking mode drinving the DC fault current towards zero; locating the fault and isolating a faulty portion from a healthy remaining portion; reconfiguring one of the power converters designated as a re-energising power converter from the fault blocking to re-energise the healthy remaining portion; and detecting a rise in the voltage level in the healthy remaining portion above a threshold level and reconfiguring the remaining power converter connected with the healthy remaining portion from the fault blocking to the normal power transmission.

A circuit breaker distribution system is configured to provide selective coordination. The system comprises a solid-state switch disposed as a main or upstream breaker and a switch with an over current protection disposed as a branch or downstream breaker. The microcontroller to: allow repeated pulses of current through to the branch or downstream breaker in an event of an overload or short circuit, choose a maximum current limit for the solid-state switch as a “chop level” such that the chop level is chosen higher than a rated current of the solid-state circuit breaker but low enough that the solid-state switch is not damaged from repeated pulses over a period of time needed to switch OFF the branch or downstream breaker and add a pulse interval after the current chops to zero but before the solid-state circuit breaker returns to an ON state for a next pulse to begin.

A circuit breaker distribution system is configured to provide selective coordination. The system comprises a solid-state switch disposed as a main or upstream breaker and a switch with an over current protection disposed as a branch or downstream breaker. The solid-state switch comprises a microcontroller including a processor and a memory, and computer-readable logic code stored in the memory which, when executed by the processor, causes the microcontroller to: allow repeated pulses of current through to the branch or downstream breaker in an event of an overload or short circuit, and choose a maximum current limit for the solid-state switch as a “chop level” such that the chop level is chosen higher than a rated current of the solid-state circuit breaker but low enough that the solid-state switch is not damaged from repeated pulses over a period of time needed to switch OFF the branch or downstream breaker.

Methods, systems, and computer readable mediums for protecting and controlling a microgrid with a dynamic boundary are disclosed. One method includes detecting a fault in a microgrid that includes a dynamic point-of-common-coupling (PCC), in response to determining that the microgrid is operating in a grid-connected mode, isolating the fault by tripping a microgrid side smart switch and a grid side smart switch that are located immediately adjacent to the fault, initiating the reclosing of the grid side smart switch, and initiating the reclosing for the microgrid side smart switch via resynchronization if the grid side smart switch is successfully reclosed, and in response to determining that the microgrid is operating in an islanded mode, isolating the fault by tripping a microgrid side smart switch that is located immediately adjacent to the fault, and initiating the reclosing of the microgrid side smart switch.

Output circuit devices for use in electric power systems may include a first output subsystem for transmitting a first signal output via an output port to a component of the electric power system, an input subsystem for receiving and monitoring the first signal output transmitted by the first output subsystem, and a second output subsystem for transmitting another signal output to the component of the electric power system. The second output subsystem is to transmit the signal output in response to an indication from the input subsystem. Intelligent electronic devices (IEDs) and associated methods may include one or more output circuit devices.

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.

The present disclosure provides a system-level protection system and method for sub/super-synchronous resonance/oscillation. The system includes a centralized protection coordinator arranged in a control center and a plurality of distributed protection relays arranged in a plurality of transformer substations or wind farms. Each distributed protection relay is configured to acquire a sub/super-synchronous impedance of the wind farm. The centralized protection coordinator is configured to acquire the sub/super-synchronous impedances measured by the plurality of distributed protection relays, to obtain a sub/super-synchronous aggregate impedance of the system according to a preset circuit topology and the sub/super-synchronous impedances, and to generate a system-level protection signal when the sub/super-synchronous aggregate impedance does not meet a stable condition. Each distributed protection relay is further configured to initiate a system-level protection according to the system-level protection signal.

An electronic device for series connection on a power supply line includes a plurality of switches and a control unit configured to perform the following steps: operating error detection means during operation of the device in a first mode; operating the device in a second mode in response to an erroneous power state being detected by the error detection means during operation of the device in the first mode; operating the error detection means during operation of the device in the second mode in order to determine an error location associated with the erroneous power state detected by the error detection means during operation of the device in the first mode.

A protection device, externally connectable to an existing circuit breaker with zone selective interlock functionality, enables a circuit breaker to implement directional zone selective interlock. The protection device includes a first input port and a first output port connectable to a circuit breaker, and second and third ports for connecting to a protection device of another circuit breaker and for transmitting interlock signals via an input bus and an output bus inside the EDP. A control unit is configured to enable one of the second and third ports as a second input port and the other as a second output port according to the direction of current currently flowing through the circuit breaker; and configured to forward an interlock signal from the first input port to the output bus and to forward an interlock signal on the input bus received from the second input port to the first output port.

A systems and methods for monitoring an electrical power distribution grid including a plurality of sensor devices forming a sensor wireless network are disclosed. Each sensor device monitors and measures attributes of line current for an associated electrical power distribution line at a selected location. A sensor device detects a fault on the branch of the power grid, determines if the one of the plurality of sensors is at a tail end, sends a fault detected message to an adjacent upstream sensor, or otherwise sends a sleep command to an adjacent downstream sensor from the tail end sensor to disable transmission.