A self-powered current sensor is described. The self-powered current sensor including an electrical signal input configured to receive a current signal. Further, the self-powered current sensor includes a power circuit configured to generate a power voltage from an electrical signal. The self-powered current sensor also includes a variable resistor configured to set a value corresponding to one or more indicators on the electrical sensor and an amplifier coupled with a variable resistor and a power circuit. And, the self-powered current sensor includes an alarm coupled with an amplifier, an alarm configured to activate based on a value set by said variable resistor.

In some examples, a device includes a memory configured to store a pre-warning threshold level for a parameter of a power switch. The device also includes a logic circuit configured to receive a signal from a controller and set the pre-warning threshold level in response to receiving the signal from the controller. The logic circuit is also configured to determine that a magnitude of the parameter of the power switch does not satisfy the pre-warning threshold level. The logic circuit is further configured to output an alert to the controller in response to determining that the magnitude of the parameter does not satisfy the pre-warning threshold level.

An overcurrent protection device is for protecting a load arranged in a DC grid. The load is coupled to a supply busbar, which is connectable to a supply potential of the DC grid, in the DC grid via the overcurrent protection device. The overcurrent protection device is designed to ascertain a current trigger value based upon a detected value of a current flowing through the overcurrent protection device and a trigger characteristic which is assigned to the load and is based on the current; compare the current trigger value with a threshold, and either trigger the overcurrent protection device or not, based upon the result of the comparison. The current is taken into consideration together with a first or a second factor in the trigger characteristic based upon the current direction.

A device or system for use with an electric power system is provided. The electric power system has a first bus, a second bus, a third bus, a first line between the first and second buses, and a second line between the third bus and one of the first and second buses. The device or system is operative to determine, responsive to at least one trip event, one or several updated impedances of an equivalent model across a line.

A relay control apparatus according to an embodiment of the present disclosure includes: a relay disposed on a main path between a battery cell and a pack terminal and for electrically connecting or disconnecting the main path according to an operation state of the relay; and a comparator for receiving a comparison voltage from the main path and outputting a result signal to the relay based on a difference between a reference voltage and the comparison voltage, the relay is receives the result signal and controls the operation state of the relay to a turn-on state or a turn-off state according to the magnitude of the received result signal.

A method for characterizing power quality events in an electrical system includes deriving electrical measurement data for at least one first virtual meter in an electrical system from (a) electrical measurement data from or derived from energy-related signals captured by at least one first IED in the electrical system, and (b) electrical measurement data from or derived from energy-related signals captured by at least one second IED in the electrical system. In embodiments, the at least one first IED is installed at a first metering point in the electrical system, the at least one second IED is installed at a second metering point in the electrical system, and the at least one first virtual meter is derived or located at a third metering point in the electrical system. The derived electrical measurement data may be used to generate or update a dynamic tolerance curve associated with the third metering point.

A control system and methods for a digital circuit breaker are provided. The system comprises a digital circuit breaker, an electric trace heater electrically connected to the digital circuit breaker, a temperature sensor, and a controller device in communication with the digital circuit breaker and the electric trace heater. The controller device includes a processor in communication with the temperature sensor, and the processor is configured to receive a temperature value from the temperature sensor, construct a time-current curve for the digital circuit breaker based on the temperature value, and transmit data representative of the time-current curve to the digital circuit breaker.

An eFuse for use in high voltage applications is disclosed. In one embodiment, an apparatus includes a solid-state switch having source and drain terminals connected to switch a load current from a high voltage source through a high voltage load. The apparatus also includes a sense circuit that senses a voltage between the switch source and drain terminals and turns off the switch when the voltage exceeds a selected voltage level.

A DC-overcurrent detector includes: at least one electric line passing the detector from a source terminal of the detector to a load terminal of the detector; at least one first sensor for monitoring an electric current in the at least one electric line and outputting a current measurement signal; at least one current flow direction sensor for distinguishing a current flow direction of the electric current in the at least one electric line between a first direction from the source terminal to the load terminal and a second direction from the load terminal to the source terminal, and outputting a current flow direction signal; a comparator unit for comparing an actual value of the current measurement signal with a threshold criterion, and outputting a trigger signal at a trigger output if a value of the current measurement signal reaches the threshold criterion; and a threshold criterion unit.

An electric switch includes a thermal tripping unit which, when a thermal budget acting on it is exceeded, trips and switches off the electric switch. In an embodiment, the tripping unit includes an adjustment module which, as a function of an accessory connected to the electric switch, uses an actuating element to set a tripping element of the thermal tripping unit such that the heat effect of the accessory is compensated for in the event of tripping.