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.

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.

A method may include receiving a command to move one or more armatures of a switching device from a first position that electrically couples a first contact to a second contact to a second position that electrically uncouples the first contact from the second contact. The method may also include selecting a current zero-crossing point along an electric waveform indicative of a change in current through the first contact and the second contact as a synchronization point, determining a predicted current zero-crossing point by adding a period measurement associated with a previously detected current zero-crossing point or a previously detected line-to-line crossing point in the electric waveform to the synchronization point, and transmitting a command to the switching device to move the armatures from the first position to the second position before or at the predicted current zero-crossing point.

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.

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.

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.

A method, device and computer readable medium are provided for determining the closing time of a circuit breaker. In an embodiment, the method includes: sampling a voltage signal of a target phase in the three-phase voltage signal of the circuit breaker; determining a first time period according to a voltage value of the sampled voltage signal, a voltage signal in the first time period including a voltage jump point of the voltage value; finding a voltage jump point of a voltage value in the first time period according to a change in the voltage value of the voltage signal in the first time period; and determining the closing time of a target phase of the circuit breaker according to the found sampling time of the voltage jump point.

A method for synchronizing opening of a circuit breaker is presented. The circuit breaker is arranged to interrupt a current to an inductive load. The method is performed in a control device (2) and comprises measuring (S100) a reference signal as a function of time for a circuit breaker (1) connected to an inductive load (5), obtaining (S110) an indication of a power factor of the inductive load through the circuit breaker, determining (S120) an arcing time for opening of the circuit breaker, the arcing time being dependent on the obtained indication of a power factor, predicting (S130) a zero crossing of a current through the circuit breaker based on the measured reference signal, and providing (S140) contact separation of a contact pair of the circuit breaker at a point of time before the predicted zero crossing, the point of time being determined by the determined arcing time and the predicted zero crossing. A control device, a circuit breaker arrangement, and a computer program for synchronizing opening of a circuit breaker are also presented.

The present disclosure provides a high voltage and high current switch with zero-phase waiting and a control method. The switch includes two or more switching units connected in series, each of the switch unit modules includes a main switch circuit, an auxiliary switch circuit, a voltage-equalizing power supply circuit unit, a switch control and communication circuit unit, and a current transformer; and the auxiliary switch circuit and the voltage-equalizing power supply circuit unit are connected in parallel between two ends of the main switch circuit, and the current transformer is connected to the main switch circuit; an output of the current transformer is connected to the voltage-equalizing power supply circuit unit which supplies power to the switch control and communication circuit unit, and the switch control and communication circuit unit is configured to control the closing and opening of a main relay and an auxiliary relay.

A diagnostic apparatus diagnoses a symptom of anomaly in a device that operates for making or breaking a circuit. The diagnostic apparatus includes a factor probability calculation unit that calculates a factor probability. The factor probability calculation unit calculates a factor probability for each matter that may be a factor in a symptom observed in the device, the factor probability being a probability that the matter truly corresponds to a factor for the observed symptom. The diagnostic apparatus can obtain useful information for improving the operating state of the device.