The invention discloses a commutation failure protection method, and apparatus, computer device and storage medium thereof. The method comprises: collecting three-phase AC currents on a valve-side of a converter, a DC current on a high-voltage side and a DC current on a neutral terminal; selecting a minimum value of an absolute value of the three-phase AC currents on the valve side as an AC characteristic quantity, and selecting a maximum value of the DC current on the high-voltage side and the DC current on the neutral terminal as a DC characteristic quantity; according to the AC characteristic quantity and the DC characteristic quantity, constructing a minimum characteristic quantity; comparing the minimum characteristic quantity with a first preset threshold, and outputting a commutation judgment result; according to the commutation judgment result, constructing a commutation time interval; comparing the commutation time interval with a second preset threshold and a third preset threshold, and outputting a commutation failure protection judgment result to determine whether a commutation failure occurs. The invention uses minimum current sequence characteristics to track a commutation process of a converter valve, and when a commutation failure occurs, it may make timely, accurate and reliable judgment, thereby ensuring safe operation of valve equipment.

A protection circuit for connecting and disconnecting to a DC power source, and a DC operated device including such a protection circuit. The protection circuit has input terminals for receiving power from a DC power source and output terminals for providing power to a DC operated device; a first stage with a voltage measurement circuit coupled between the input terminals; and a second stage following the first stage including a pre-charge control circuit. The protection circuit further includes a digital controller arranged for controlling activating and de-activating a local PSU for supplying power to electronics of the DC operated device. The digital controller is arranged for measuring a voltage of the voltage measurement circuit and de-activating the local PSU when detecting a voltage drop on the first input terminal that exceeds a predetermined threshold dip and/or threshold slope.

Provided are embodiments for a system for performing input power detection. The system includes a first input for a first power source, a second input for a second power source, and a controller that is operably coupled to the first power source and the second power source. The system also includes a first path connecting a first circuit to the first power supply, wherein the first path comprises a first field effect transistor (FET) that is operated to inhibit leakage current flow to the first circuit, and a second path connecting a second circuit to the second power supply, wherein the second path comprises a second FET that is operated to inhibit leakage current flow to the second circuit. Also provided are embodiments for a method for performing input power detection.

In a described example, a circuit includes a synchronization control circuit having a sync input and a sync control output, in which the sync input is coupled to a sync terminal configured to receive an external clock signal. An internal clock generator circuit has a control input and an output. The control input is coupled to the sync control output. An output circuit has first and second signal inputs, a mode control input and a clock output. The first signal input is coupled to the sync input, and the second signal input of the output circuit is coupled to the output of the internal clock generator circuit. The mode control input is coupled to the sync control output, and the clock output adapted to be coupled to a controller.

A low-voltage protection switch unit, such as a motor protection switch, includes: at least an external conductor line, from an external line supply terminal of the low-voltage protection switch unit to an external line load terminal of the low-voltage protection switch unit; a neutral conductor line, from a neutral conductor terminal of the low-voltage protection switch unit to a neutral conductor load terminal of the low-voltage protection switch unit; a mechanical bypass switch arranged in the external conductor line; a semiconductor circuit arrangement connected in parallel with the mechanical bypass switch; an electronic control unit for actuating the mechanical bypass switch and the semiconductor circuit arrangement in a specifiable manner; and a current measurement arrangement connected to the electronic control unit, the current measurement arrangement being arranged at least in the external conductor line. The electronic control unit switches the semiconductor circuit arrangement on/off in a specifiable clocked manner.

There is provided a protection device capable of protecting a load drive system at an appropriate timing according to the temperature of a power semiconductor.

A protection device includes: a capacitor that outputs a voltage according to a charge accumulated by a first current; and a protection circuit that determines whether or not the voltage output by the capacitor exceeds a certain threshold value, generates a second current having a magnitude according to information related to the temperature of a power semiconductor which drives a load, and changes the magnitude of the first current based on the generated second current.

A differential protection method for monitoring a line of a power grid. Current phasor measured values are captured at the ends of the line and transmitted to an evaluation device which is used to form a differential current value with current phasor measured values temporally allocated to one another. Time delay information indicating the time delay between local timers of the measuring devices is used for the temporal allocation of the current phasor measured values captured at different ends, and a fault signal indicating a fault affecting the line is generated if the differential current value exceeds a predefined threshold value. The reliability of the time synchronization is further increased by forming a quotient of the current phasor measured values to form an asymmetry variable, that is used to check a transit time difference of messages transmitted via the communication connection in different directions.

Systems and methods are disclosed for detecting node outages in a mesh network. A tracking node in the mesh network detects a set of signals originating from a tracked node in the mesh network. The set of signals includes beacons or communication messages transmitted by the tracked node. The tracking node determines that a threshold number of the beacon intervals have passed since receiving the most recent signal from the tracked node. The tracking node performs outage validation based on data received from another node in the mesh network and updates the status of the tracked node. Based on the updated status, the tracking node outputs a ping to the tracked node requesting a response to the ping. When the response to the ping is not received from the tracked node, the tracking node transmits an outage alarm message to a next topologically higher layer of the mesh network.

A ground fault circuit interrupter is provided, including a sensor module, a leakage protection module, a self-test module and a tripping module. The sensor module is configured to generate a sensor current according to a detection signal. The leakage protection module is configured to: generate a trip driving signal in a detection stage according to the sensor current; and generate a trip driving signal in a non-detection stage after the self-test module has a fault. The self-test module is configured to generate the detection signal in the detection stage, and determine that the leakage protection module does not have a fault if the leakage protection module generates the trip driving signal. The tripping module is configured to respond to the trip driving signal generated in the non-detection stage to disconnect a load from a power supply circuit, and not respond to the trip driving signal generated in the detection stage.

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.