In a method for protecting lines, in which a reactor device for reactive power compensation is provided on an electrical line, a resonant current is measured on the line side of the reactor device by a first measuring device after an opening of a circuit breaker. A voltage is measured by a second measuring device after the opening of the circuit breaker. A current in the reactor device is calculated by an evaluation device on a basis of the measured voltage, and the calculated current is subtracted from the measured resonant current by the evaluation device in order to obtain a corrected current.

Described herein are improvements for a power system by operating the power system using updated performance characteristics for a protection device. In one example, a method includes operating the power system based on a first operational curve for a first protection device of the one or more protection devices. The first operational curve indicates conditions upon which the first protection device will trip. The method also provides obtaining trip information describing conditions that cause the first protection device to trip at each of one or more trip occurrences during operation of the power system. The method further provides adjusting the first operational curve to generate an adjusted first operational curve that reflects the trip information and operating the power system based on the adjusted first operational curve.

It is disclosed a motor thermal protection device and operation method thereof. The motor thermal protection device utilizes a power supply of a motor for power supplying and comprises: a capacitor timing circuit, configured to time after the motor is powered off; a power-off time determining unit, configured to perform a reading operation of reading an output voltage of the capacitor timing circuit after the motor is powered on, and determine a power-off time from when the motor is powered off to when the motor is powered on according to the output voltage; and a heat accumulation calculating unit, configured to calculate a remaining heat accumulation when the motor is powered on according to the power-off time and a heat accumulation when the motor is powered off.

A method for identifying type of a grid automatically and an inverter device thereof are provided. The inverter device comprises a power line L1, a power line L2, a neutral line N and a ground line electrically connectable to a first power line, a second power line, a neutral line and a ground line of the grid, respectively. The method comprises: sampling at least two of voltages between L1 and L2, between L1 to N and between L2 to N when the two neutral lines are connected, and identifying the type of the grid based on the sampling result; and sampling the voltage between L1 and L2 when the two neutral lines are not connected, sampling at least one of a voltage between L1 and GND and between L2 and GND with cooperation of a grid-connected switching unit, and identifying the type of the grid based on the sampling results.

A circuit may include an electronic switch that has a load current path coupled between an output node and a supply node and that is configured to connect or disconnect the output node and the supply node in accordance with a drive signal. Further, the circuit includes a monitoring circuit that is configured to receive a current sense signal, which represents the load current passing through the load current path, and that is further configured to determine a protection signal based on the current sense signal, a state of the monitoring circuit, and at least one wire parameter. The wire parameter characterizes a wire that is—during operation—connected to the output node, and the protection signal is indicative of whether to disconnect the output node from supply node. Further, the circuit includes a protection circuit connected to the monitoring circuit.

The control apparatus includes an electrical signal detection unit, a control unit, a contactor, a first execution unit, a protection unit, and a second execution unit. The electrical signal detection unit detects an electrical signal on a loop, and send the electrical signal to the control unit. The control unit generates a control signal, and send the control signal to the first execution unit. The contactor is connected to the loop. The first execution unit controls the contactor to be closed or opened, where when the contactor is closed, the loop is connected, and when the contactor is opened, the loop is disconnected. The protection unit detects a current value on the loop when the contactor is closed, where an opening instruction is sent to the second execution unit when the current value reaches a trip threshold. The second execution unit opens the contactor when receiving the opening instruction.

An arc detection system for an aircraft high voltage and direct current electrical circuit which includes a sensor sensing high-frequency magnetic fields created by current pulses, a signal conditioning block, a database including a time threshold, status signals of events occurring in aircraft normal operation procedures, a processing unit configured to calculate a statistical dispersion of the high-frequency magnetic fields of the current pulses of the signals measured by the sensor, calculate a threshold under no-arc conditions as a function of the previous measured signals, check if the signals measured by the sensor are above the threshold under no arc-conditions during the time threshold, if positive, check if any status signal of events due to normal operation procedures has been activated, and if negative, activate the operation of an electrical protection.

A circuit protective system. The system includes an output controlling enablement of a transistor and an input sensing an operational parameter associated with the transistor. The system also includes detection circuitry providing an event fault indicator if the operational parameter violates a condition. The system also includes protective circuitry disabling the transistor in response to the event fault indicator and subsequently selectively applying an enabling bias to the transistor; the enabling bias is selected from at least two different bias levels and in response to a number of event fault indications from the detection circuitry.

A circuit breaker for an electric load includes first and second terminals; a number of first separable contacts each electrically connected between one of the first terminals and one of the second terminals; a first mechanism to open, close or trip open the first contacts; a number of second separable contacts each electrically connected in series with a corresponding one of the first contacts; a second mechanism to open or close the second contacts; a processor to cause the second mechanism to open or close the second contacts, annunciate through one of the second terminals a power circuit electrical parameter for the electric load, receive from a number of the second terminals a confirmation from or on behalf of the electric load to cause the second mechanism to close the second contacts, and determine a fault state operatively associated with current flowing through the second contacts.

Compliant electrical circuit protection devices are described for use in hazardous environments without presenting ignition risks for potentially explosive environmental conditions. Sensing features and systems may evaluate wiring limits and user selected settings for compatibility, detect loose connections and operating parameters to ensure safe operation of the device, and to intelligently diagnose and manage issues of concern for the circuit protection devices as well as the larger electrical power system.