A method for controlled switching of a circuit breaker is described. The method includes initiating operation of the circuit breaker at an initiation time derivable from an initiation time function by calculating a value of the initiation time function with respect to a command instant. The initiation time function is a sum of the command instant and a command delay time. The initiation time function depends on a first parameter and a second parameter. At least one of: the partial derivative of the initiation time function with respect to the first parameter is dependent on the second parameter or the partial derivative of the initiation time function with respect to the second parameter is dependent on the first parameter. Further, a system for controlled switching according to the method and a circuit breaker including the system are described.

A circuit breaking apparatus comprises a circuit breaker, a motor drive system, and a controller. The circuit breaker is electrically connectable to a power line. The motor drive system is mechanically coupled to the circuit breaker and configured to operate the circuit breaker such as to perform a movement including at least an opening movement from a closed position to an open position, thereby electrically interrupting the power line. The controller includes a model of at least one of the motor drive system and the circuit breaker.

The controller is configured to receive reference travel curve information of the movement; generate actuator information from the reference travel curve information based on the model; and output the actuator information.

A method may include receiving a command to move one or more armatures configured to move between a first position that electrically couples one or more first movable contacts to one or more second contacts and a second position that electrically uncouples the one or more first movable contacts from the one or more second contacts. The method may also include determining an operating frequency of the system, dynamically determining an open-before-zero target point associated with the operating frequency, and transmitting a command to the switching device to move the one or more armatures from the first position to the second position at the open-before-zero target point to normalize the arc energy over the operating frequency range.

A monitoring system includes a frame, a fixed contact, a moveable contact, a drive mechanism, and a linkage mechanism, wherein the fixed contact is fixed in position with respect to the frame, and wherein the linkage mechanism is coupled to the drive and the moveable contact, and wherein activation of the drive is configured to move the linkage mechanism such that the moveable contact is moved towards or away from the fixed contact, and wherein the monitoring system comprises a sensor system having a position sensor and a processor, the position sensor configured to be positioned with respect to the frame and the linkage mechanism such that lateral movement of a part of the linkage mechanism generates at least one displacement signal; and the processor configured to convert the at least one displacement signal to a displacement movement of the moveable contact toward or away from the fixed contact.

The present invention discloses a system for limiting a peak current of short-circuit current, which comprises a first a first high-frequency branch configured to provide a first high-frequency current to a first switch (1SKa) of a first phase branch of a three-phase AC when the first phase branch occurs a short-circuit, wherein the first high-frequency current is configured to cause a zero-crossing point of a short-circuit current to appear before a zero-crossing point of the three-phase AC; a second high-frequency branch configured to provide a second high-frequency current to a second switch (1SKc) of a second phase branch of the three-phase AC when the second phase branch occurs a short-circuit, wherein the second high-frequency current is configured to cause a zero-crossing point of a short-circuit current to appear before a zero-crossing point of the three-phase AC, a third phase branch of the three-phase AC connected in parallel with the first phase branch and the second phase branch and configured to always supply power. The present invention superimposes the high-frequency current on the original short-circuit current of the switch, thereby the total time from the arc generation to extinction at the zero-crossing point and then to the judgement by the control system is shorter than the time that the short-circuit current peak appears. Therefore, it can effectively lower the damage of the short-circuit current peak to the dynamic stability of the switch and lower the impact on system equipment.

A system for limiting a peak current of short-circuit current comprises a first high-frequency branch configured to provide a first high-frequency current to a first switch (1SKa) of a first phase branch of a three-phase AC when the first phase branch occurs a short-circuit; a second high-frequency branch configured to provide a second high-frequency current to a second switch (1SKc) of a second phase branch of the three-phase AC when the second phase branch occurs a short-circuit; and a third phase branch of the three-phase AC connected in parallel with the first phase branch and the second phase branch and configured to always supply power.

A contactor apparatus and method for operating the contactor apparatus can include a contactor assembly with a contactor coil operably coupled to a contactor switch. One or more sensors can be provided in the contactor assembly adapted to measure one or more aspects of the contactor assembly. Based upon the measured aspects, a controller can initiate operation of the contactor switch to effectively toggle the contactor switch at a zero-crossing point along an alternating current waveform.

A circuit breaker comprises a solid-state bidirectional switch, a switch control circuit, current and voltage sensors, and a processor. The solid-state bidirectional switch is connected between a line input terminal and a load output terminal of the circuit breaker, and configured to be placed in a switched-on state and a switched-off state. The switch control circuit control operation of the bidirectional switch. The current sensor is configured to sense a magnitude of current flowing in an electrical path between the line input and load output terminals and generate a current sense signal. The voltage sensor is configured to sense a magnitude of voltage on the electrical path and generate a voltage sense signal. The processor is configured to process the current and voltage sense signals to determine operational status information of the circuit breaker, a fault event, and power usage information of a load connected to the load output terminal.

An electric device comprises a first and second voltage sensor, a current sensor, an actuator and a controller. The first voltage sensor senses a first voltage at a first contact of a switch inside the electric device and generates a first voltage signal indicating the first voltage, the first contact of the switch coupled to a source line. The second voltage sensor senses a second voltage at a second contact of the switch and generates a second voltage signal indicating the second voltage, the second contact is coupled to a reactive component. The current sensor senses a current at the second contact of the switch and generates an output signal indicating the current. The controller is coupled to the voltage sensors, the current sensor and the actuator and causes, based on at least one of the voltage and current signals, the actuator to actuate one of the contacts to execute switching at a predetermined point of the first voltage.

The present invention provides a method of determining an electrical operating time of a circuit breaker (140) in a multiphase electrical system having a subsystem (160) at an electric potential resulting from electrical characteristics of electrical components within the subsystem. The method comprises monitoring (145) the voltage of the subsystem in the first phase, determining a first rate of change from the monitored voltage in the first phase, detecting at least one instance of switching based on the first rate of change, determining an electrical operating time of the circuit breaker based on the detected at least one instance of switching and an instance at which a command for switching was provided to the circuit breaker.