A power switch controller includes a condition detector, a zero crossing detector, a retimer, and a driver. The condition detector detects a change in a sense signal towards a first or second condition. The zero crossing detector detects zero crossings in an AC powerline signal. The power switch controller drives a latching relay that connects a load to powerlines. The power switch controller activates or deactivates the latching relay based on the sensed condition, and retimes activation and deactivation pulses to align the relay contact opening and closing times to coincide with the AC powerline zero crossings, compensating for contact travel times. The activation and deactivation pulses have a duration of max 20 ms, and an amplitude of at least 110% of the maximum sustainable voltage for the relay coil(s). A power-on reset deactivates the relay, aligned with a second AC zero crossing.

A power switch controller includes a condition detector, a zero crossing detector, a retimer, and a driver. The condition detector detects a change in a sense signal towards a first or second condition. The zero crossing detector detects zero crossings in an AC powerline signal. The power switch controller drives a latching relay that connects a load to powerlines. The power switch controller activates or deactivates the latching relay based on the sensed condition, and retimes activation and deactivation pulses to align the relay contact opening and closing times to coincide with the AC powerline zero crossings, compensating for contact travel times. The activation and deactivation pulses have a duration of max 20 ms, and an amplitude of at least 110% of the maximum sustainable voltage for the relay coil(s). A power-on reset deactivates the relay, aligned with a second AC zero crossing.

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.

In aspects, the present invention provides a method for controlled energizing of a transformer (150) being connected to a first electrical subsystem (110) through a first circuit breaker (140). The method comprises acquiring electrical current waveform in a first phase of the transformer during a closing operation of the first circuit breaker at an instance for switching determined by a controller (130), determining a first peak (310) in the current in the first phase within a first predetermined time window (Tpw), calculating a first correction factor for adjusting the instance for switching in the first phase, and adjusting the instance for switching based on the calculated first correction factor for performing a next controlled energization at the adjusted instance of switching in the first phase.

In aspects, the present invention provides a method for controlled energizing of a transformer (150) being connected to a first electrical subsystem (110) through a first circuit breaker (140). The method comprises acquiring electrical current waveform in a first phase of the transformer during a closing operation of the first circuit breaker at an instance for switching determined by a controller (130), determining a first peak (310) in the current in the first phase within a first predetermined time window (Tpw), calculating a first correction factor for adjusting the instance for switching in the first phase, and adjusting the instance for switching based on the calculated first correction factor for performing a next controlled energization at the adjusted instance of switching in the first phase.

A control system may include a processor that may receive a first dataset associated with power properties of a rotating load device coupled to a relay device. The processor may also determine frequency properties based on the power properties and determine a switching profile to control moving a first armature of three armatures in the relay device based on the frequency properties. The switching profile is configured to control movement of the first armature between a first position and a second position, and wherein the switching profile comprises a firing angle for moving the first armature with respect to an electrical waveform, a second armature, and a third armature. The processor may then control a current provided to a relay coil of the relay device based on the switching profile, such that the relay coil causes the first armature to move.

A control system may include a processor that may receive a first dataset associated with power properties of a rotating load device coupled to a relay device. The processor may also determine frequency properties based on the power properties and determine a switching profile to control moving a first armature of three armatures in the relay device based on the frequency properties. The switching profile is configured to control movement of the first armature between a first position and a second position, and wherein the switching profile comprises a firing angle for moving the first armature with respect to an electrical waveform, a second armature, and a third armature. The processor may then control a current provided to a relay coil of the relay device based on the switching profile, such that the relay coil causes the first armature to move.

A load control device may control power delivered to an electrical load from an AC power source. The load control device may include a controllably conductive device adapted to be coupled in series electrical connection between the AC power source and the electrical load, a zero-cross detect circuit configured to generate a zero-cross signal representative of the zero-crossings of an AC voltage. The zero-cross signal may be characterized by pulses occurring in time with the zero-crossings of the AC voltage. The load control device may include a control circuit operatively coupled to the controllably conductive device and the zero cross detect circuit. The control circuit may be configured to identify a rising-edge time and a falling-edge time of one of the pulses of the zero-cross signal, and may control a conductive state of the controllably conductive device based on the rising-edge time and the falling-edge time of the pulse.

A load control device may control power delivered to an electrical load from an AC power source. The load control device may include a controllably conductive device adapted to be coupled in series electrical connection between the AC power source and the electrical load, a zero-cross detect circuit configured to generate a zero-cross signal representative of the zero-crossings of an AC voltage. The zero-cross signal may be characterized by pulses occurring in time with the zero-crossings of the AC voltage. The load control device may include a control circuit operatively coupled to the controllably conductive device and the zero cross detect circuit. The control circuit may be configured to identify a rising-edge time and a falling-edge time of one of the pulses of the zero-cross signal, and may control a conductive state of the controllably conductive device based on the rising-edge time and the falling-edge time of the pulse.

Systems and methods for contact erosion mitigation are provided. To perform contact erosion mitigation, an order of opening/closing poles and/or contact relays of particular poles is altered, resulting in a sharing of potential arcing conditions amongst the poles/contact relays of these poles.