There is disclosed a circuit breaker arrangement for interrupting a current flowing through a direct current (DC) transmission line including a semiconductor switching device and a pulse injection circuit configured to inductively inject into the transmission line a pulse current that opposes the current flowing through the transmission line to thereby reduce the current in the transmission line to cause the semiconductor switching device to turn-off to interrupt the path for the current flow through the transmission line.

In a line to line fault detection and protection system, a source end power supply supplies power to a remote load over a transmission line and monitors the dynamic behavior of a transmission line power characteristic. If that dynamic behavior is outside a constraint that is actively imposed on the transmission line dynamic behavior by a load end power conditioning system, a possible line to line fault is recognized. The preferred power characteristic is current and the preferred constraint is a maximum rate of change of current drawn from the transmission line by the load end power conditioning system.

An electronic device includes a monitoring unit that monitors a voltage of a first terminal that receives power supplied from a power supply apparatus, and a control unit that performs control so as to stop the power supply from the power supply apparatus if a voltage variation per unit time of the first terminal is not less than a first predetermined value or the voltage of the first terminal is not less than a second predetermined value.

A method and device for starting direct-current (DC) transmission line protection, and a storage medium. The method includes: determining whether a sudden change of a DC line current at a present moment is greater than a sum of a memory start threshold and a maximum value in sudden changes of the DC line current within a time period preceding the present moment that is multiplied by a preset proportional coefficient, the time period being a time period between a moment preceding the present moment by a first duration and a moment preceding the present moment by a second duration; and starting DC transmission line protection in response to determining that the sudden change of the DC line current at the present moment is greater than the sum.

In a line to line fault detection and protection system, a source end power supply supplies power to a remote load over a transmission line and monitors the dynamic behavior of a transmission line power characteristic. If that dynamic behavior is outside a constraint that is actively imposed on the transmission line dynamic behavior by a load end power conditioning system, a possible line to line fault is recognized. The preferred power characteristic is current and the preferred constraint is a maximum rate of change of current drawn from the transmission line by the load end power conditioning system.

A motor control apparatus for controlling a power supply to an electrical motor (M) connected to an output terminal (3) of the motor control apparatus (1) comprising: an overcurrent protection circuit (1A) having a power switch (5) through which the electrical motor (M) receives an electrical load current (I.sub.L) and having a sensor component (4) connected in series with the power switch (5) and adapted to generate directly a voltage drop (ΔU.sub.4) corresponding to the current rise speed of the electrical load current (I.sub.L) flowing from an input terminal (2) of the motor control apparatus (1) via the sensor component (4) and the power switch (5) to the output terminal (3) and having a driver circuit (6) adapted to detect an occurring overcurrent depending on the voltage drop (ΔU.sub.4) generated by the sensor component (4) and/or depending on a voltage drop (ΔU.sub.5) along the power switch (5) and adapted to switch off said power switch (5) upon detection of an overcurrent within a switch-off period of less than one millisecond; and/or comprising a power supply control circuit (10) having a sensor component (9) adapted to measure at the input terminal (2) a supply voltage notified to a control unit (8) of the motor control apparatus (1) adapted to control an electrical power supplied to the electrical motor (M) depending on an operation mode of the electrical motor (M).

A method and device for starting direct-current (DC) transmission line protection, and a storage medium. The method includes: determining whether a sudden change of a DC line current at a present moment is greater than a sum of a memory start threshold and a maximum value in sudden changes of the DC line current within a time period preceding the present moment that is multiplied by a preset proportional coefficient, the time period being a time period between a moment preceding the present moment by a first duration and a moment preceding the present moment by a second duration; and starting DC transmission line protection in response to determining that the sudden change of the DC line current at the present moment is greater than the sum.

In a method for monitoring a high-voltage DC transmission the following are predefined: an amperage threshold value for an amperage of the high-voltage DC transmission, at least one interval length for time intervals and, for each predefined interval length, a change threshold value for a change in the amperage averaged over time intervals of the interval length. The amperage for each terminal of the high-voltage DC transmission is determined, and a change in the amperage averaged over time intervals of the interval length is determined for each predefined interval length. A DC error is determined if the magnitude of the amperage of at least one terminal is greater than the amperage threshold value or if, for an interval length, the magnitude of the averaged change in the amperage of at least one terminal is greater than the change threshold value predefined for the interval length.

There are provided a device for preventing an entire cabinet from being powered down, a cabinet, and a method for preventing an entire cabinet from being powered down. The device includes a diode and a first protection circuit. An anode of the diode is grounded, a cathode of the diode is connected to an external voltage supplying copper busbar via the first protection circuit, and the diode is connected in parallel with an external node. The first protection circuit is arranged to monitor a current flowing through the diode, and cut off a connection line between the diode and the voltage supplying copper busbar in a case that the current exceeds a preset fusing current threshold.

A power supply system includes a power supply circuit, a sensor of the current flowing through a terminal of the power supply circuit and a protection circuit. The protection circuit includes a differentiator adapted to measure a slope of a current measurement signal and comprises a driving stage. The power supply circuit is configured to receive a disconnection signal and, alternatively, to electrically connect the internal components thereof to its terminal or electrically disconnect the internal components thereof from its terminal, as a function of the value of the disconnection signal.