A load protection and control apparatus (1) for protecting and controlling an electrical load connected to the load protection and control apparatus (1) comprising an overcurrent protection circuit (1A) having a power switch (5) through which the electrical load 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 load protection and 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 (U) notified to a control unit (8) of the load protection and control apparatus (1) adapted to control an electrical power supplied to the electrical load, wherein each input terminal (2) is configured to establish an electrical connection with a busbar (14) of a busbar system or with a current carrying wire.

A power cutoff device includes a relay unit including a switch having a connecting state to be electrically conductive and a cutoff state to be electrically non-conductive, a cutoff unit connected in series to the switch, a current detector configured to detect an object current flowing through the cutoff unit, and a controller configured to control the relay unit and the cutoff unit. The cutoff unit has a connecting state to be electrically conductive and an irreversible cutoff state to be electrically conductive. The controller is configured to obtain a changing rate of the object current with respect to time. The controller is configured to cause the switch to be in the connecting state and cause the cutoff unit to be in the connecting state if determining that the changing rate is not greater than a changing-rate threshold. The controller is configured to cause the relay unit to be in the cutoff state and cause the cutoff unit to be in the irreversible cutoff state if determining that the changing rate is greater than the changing-rate threshold. This power cutoff device has a small size.

A load control apparatus (1) for controlling a power supply to an electrical load connected to an output terminal (3) of the load control apparatus (1) comprising: an overcurrent protection circuit (1A) having a power switch (5) through which the electrical load 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 load 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 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 (1C) having a sensor component (9) adapted to measure at the input terminal (2) a supply voltage notified to a control unit (8) of the load control apparatus (1) adapted to control an electrical power supplied to the electrical load.

A load protection apparatus for protecting an electrical load connected to an output terminal (3) of the load protection apparatus (1) against overcurrent, said apparatus (1) comprising: an overcurrent protection circuit (1A) having a power switch (5) through which the electrical load receives an electrical load current (I.sub.L) via the output terminal (3) 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 load 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 depending on a voltage drop (ΔU.sub.5) along the power switch (5) adapted to switch off said power switch (5) upon detection of an overcurrent within a switch-off period.

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.

Provided is a method for monitoring DC electrical power. The method including determining a rate of change of the DC electrical power, determining whether the rate of change of the DC electrical power is greater than a predetermined threshold, when the rate of change of the DC electrical power is greater than the predetermined threshold, determining whether the rate of change of the DC electrical power is greater than the predetermined threshold for a predetermined period of time, and when the rate of change of the DC electrical power is greater than the predetermined threshold for the predetermined period of time, sending a signal indicating an interruption in the DC electrical power.

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.

A method for circuit breaker failure (CBF) protection in a power substation is disclosed. The power substation includes a first circuit breaker (CB), a second CB coupled to the first CB, a feeder coupled to the first CB and the second CB, a power plant coupled to the feeder, a first plurality of CBs coupled to the first CB, and a second plurality of CBs coupled to the second CB. The method includes sending a first stage tripping command to the first CB and the second CB to trip the first CB and the second CB responsive to a non-high current tripping command being active for a first period of time, and one of a current condition and an energization condition being satisfied for the first period of time, sending a first second-stage tripping command to the first plurality of CBs to trip the first plurality of CBs responsive to the non-high current tripping command being active for a second period of time, and one of the current condition and the energization condition being satisfied for the second period of time, and sending a second second-stage tripping command to the second plurality of CBs to trip the second plurality of CBs responsive to the non-high current tripping command being active for a third period of time, and one of the current condition and the energization condition being satisfied for the third period of time. The second period of time and the third period of time may be longer than the first period of time.

A system includes a first transistor having a first control input and first and second current terminals. The first current terminal couples to an input voltage node. A second transistor has a second control input and third and fourth current terminals. The third current terminal couples to the second current terminal at a first node. The fourth current terminal couples to an output voltage node. A drive circuit is configured to charge a capacitor maintain the first transistor in an off state responsive to a negative voltage on the input voltage node, and, responsive to a negative voltage on the input voltage node, to cause the charge from the capacitor to be used to turn off the first transistor. The system provides a voltage to a load coupled to the output voltage node.

A power supply circuit includes a power supply line through which DC power input from a first connector to a second connector is supplied to a power supply that generates a power based on the DC power; a waveform output circuit configured to output a voltage waveform sloped when an arc is occurring between the first connector and the second connector; and a control circuit configured to output to the power supply an instruction for turning off the power supply when a slope of the voltage waveform exceeds a threshold.