A sliding power contact and method includes a mobile load device connector and a socket. The mobile load device connector includes a non-current power pin having a first length, a current power pin having a second length less than the first length, a neutral pin, and a ground pin. The socket includes a non-current power contact configured to electrically couple with the non-current power pin, a current power contact configured to electrically couple with the current power pin, a neutral contact configured to electrically couple with the neutral pin, and a ground pin configured to electrically couple with the ground pin. An arc suppressor is directly coupled to at least one of the non-current power pin and the non-current power contact, wherein the arc suppressor, the non-current power pin and the non-current power contact form a current path between the current power pin and the current power contact.

A circuit breaker includes an electromechanical switch, a current sensor, a voltage sensor, and a processor. The electromechanical switch is serially connected between a line input terminal and a load output terminal of the circuit breaker, and configured to be placed in a switched-closed state or a switched-open state. The current sensor is configured to sense a magnitude of current flowing in a 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 at a point on the path between the line input and load output terminals and generate a voltage sense signal. The processor is configured to receive and process the current sense signal and the voltage sense signal to determine operational status information of the circuit breaker and determine power usage information of a load connected to the load output terminal.

Provided is a high voltage DC circuit breaker that interrupts a fault current flowing through a high voltage DC transmission line with a vacuum circuit breaker and a gas circuit breaker connected in series. The circuit breaker includes: a vacuum circuit breaker installed on a DC transmission line and operating to interrupt a current in the DC transmission line when a fault occurs on either side of the DC transmission line; a gas circuit breaker connected in series with the vacuum interrupter; an LC circuit connected in parallel with the vacuum circuit breaker and including a capacitor and a reactor connected in series to induce LC resonance; a first bidirectional switching device connected in series with the LC circuit and switching a current flowing in any of two opposite directions; and a second bidirectional switching device connected in parallel with the LC circuit.

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.

A target pole-close timing determining unit corrects a breaker characteristic correction signal of a preceding turn-on phase by using a correction amount which is proportional to an absolute value of the interpolar voltage upon turn-on of the proceeding turn-on phase, and a correction amount which is proportional to an elapsed time after a target pole-close timing of the preceding turn-on phase, to generate a subsequent phase interpolar voltage signal, and determines a target pole-close timing of the subsequent turn-on phase at a timing when the subsequent phase interpolar voltage signal is equal to or smaller than a threshold value.

The method of controlling power transmission to a load permits: to eliminate over-voltage in an electric circuit; to decrease energy losses and time of charging of an energy storing device; to increase service life of switches and provide very high reliability of power transmission to a load. The conception is following: controlling power transmission to a load from additional circuit so that current can be transferred from additional circuit to operating circuit (circuit with a load) and vice versa from operating circuit to additional circuit without interruption (without switching off) circuit of the load.

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 includes a circuit breaker housing, an air-gap switch disposed within the housing, and a first visual indicator configured to provide an indication of an open state and a closed state of the air-gap switch. The first visual indicator includes a first window that is formed as part of the circuit breaker housing, and first and second indicator elements disposed within the circuit breaker housing. The first indicator element is configured to move into position behind the first window as the air-gap switch is placed into the open state and thereby provide a visual indication of the open state of the air-gap switch. The second indicator element is configured to move into position behind the first window as the air-gap switch is placed into the closed state and thereby provide a visual indication of the closed state of the air-gap switch.

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 method for operating a medium voltage circuit breaker or recloser comprising at least one electric pole, each including a movable contact and a fixed contact, being in a closed or an open position after switching operations of the medium voltage circuit breaker or recloser, and an electromagnetic actuator, includes: monitoring a travel curve of the movable contact, the travel curve being derived by an evaluation of a shape of an applied current and a shape of an applied voltage using a mathematical representation of the electromagnetic actuator.