Abstract: A method of operating a switching device in a system. The method includes monitoring a voltage; operating the system at each of a plurality of system configurations; and, for each of the system configurations and a predetermined same opening angle relative to a reference angle of the monitored voltage, determining a suitable closing angle relative to the reference angle and storing information about the determined suitable closing angle in association with the system configuration in a database. The method then includes, determining a system configuration in the system; at the predetermined same opening angle, opening the switching device; from the database, obtaining a closing angle of the determined suitable closing angles, wherein the system configuration with which the obtained closing angle is associated in the database corresponds to the determined system configuration; and at the obtained closing angle, closing the switching device.

Abstract: A start-up method for reducing inrush current to a transformer when closing a switching device. The switching device includes three single-pole operated current interrupting means. The method includes monitoring a voltage. The method includes, for each of a sequence of iterations: at a same opening angle relative to a reference angle of the voltage, starting an opening sequence of the switching device; at a closing angle relative to the reference angle, which is shifted in relation to the closing angle of all other iterations in the sequence, starting a closing sequence of the switching device; and obtaining an indication of the overall inrush current resulting from the closing. The method includes selecting for future use with the opening angle, the closing angle of one of the iterations in which the overall inrush current is relatively low when compared with the other iterations of the sequence.

Abstract: The invention relates to a control unit for a medium voltage switching apparatus. The control unit is adapted to carry out a diagnostic method to check operating conditions of one or more components of said electric poles. The diagnostic method includes the following steps: basing on a selected ideal position curve, obtaining one or more first curves indicative of an ideal behaviour of said switching apparatus, during an opening manoeuvre or closing manoeuvre of the switching apparatus; basing on detection signals provided by a closed-loop control arrangement of said control unit, calculating one or more second curves indicative of an actual behaviour of said switching apparatus, during an opening manoeuvre or closing manoeuvre of said switching apparatus; and carrying out a comparison procedure among said first and second curves.

Abstract: The invention relates to a medium voltage switching apparatus. The medium voltage switching apparatus includes one or more electric poles, each electrically coupleable with a corresponding electric line; for each electric pole, a fixed contact and a movable contact, the movable contact being reversibly movable between a decoupled position from the fixed contact and a coupled position with the fixed contact, the movable contact moving from the decoupled position to the coupled position during an closing manoeuvre of the switching apparatus and moving from the coupled position to the decoupled position during an opening manoeuvre of the switching apparatus; and actuating means adapted to actuate the movable contacts of the one or more electric poles. A control unit is adapted to select and carry out a selectable control routine in response to receiving an input signal at an input arrangement corresponding to the selectable routine.

Abstract: The present invention relates to a method for controlling a motor-driven vacuum circuit breaker. The method comprises initiate opening (S100) the circuit breaker, wherein the circuit breaker moves with an average opening speed of a contact pair of the circuit breaker, from a closed position to an open position of the circuit breaker, and decelerating (S110) the opening speed of the contact pair to below the average opening speed before the open position is reached to avoid overshoot, and initiate closing (S120) the circuit breaker, wherein the circuit breaker moves with an average closing speed of the contact pair, from the open position to the closed position, and decelerating (S130) the closing speed of the contact pair to below the average closing speed before contact touch at the closed position, wherein the circuit breaker moves with the decelerated speed at contact touch. A motor-driven vacuum circuit breaker, a computer program and a computer program product are also presented.

Abstract: The present invention relates to a method for controlling a motor-driven vacuum circuit breaker. The method comprises initiate opening (S100) the circuit breaker, wherein the circuit breaker moves with an average opening speed of a contact pair of the circuit breaker, from a closed position to an open position of the circuit breaker, and decelerating (S110) the opening speed of the contact pair to below the average opening speed before the open position is reached to avoid overshoot, and initiate closing (S120) the circuit breaker, wherein the circuit breaker moves with an average closing speed of the contact pair, from the open position to the closed position, and decelerating (S130) the closing speed of the contact pair to below the average closing speed before contact touch at the closed position, wherein the circuit breaker moves with the decelerated speed at contact touch. A motor-driven vacuum circuit breaker, a computer program and a computer program product are also presented.

Abstract: The invention relates to a medium voltage switching apparatus. The medium voltage switching apparatus comprises: one or more electric poles, each electrically coupleable with a corresponding electric line; for each electric pole, a fixed contact and a movable contact, said movable contact being reversibly movable between a decoupled position from said fixed contact and a coupled position with said fixed contact, said movable contact moving from said decoupled position to said coupled position during an closing manoeuvre of the switching apparatus and moving from said coupled position to said decoupled position during an opening manoeuvre of the switching apparatus; actuating means adapted to actuate the movable contacts of said one or more electric poles. The switching apparatus is operatively coupled with or comprises a control unit to control said actuating means.

Abstract: The invention relates to a control unit for a medium voltage switching apparatus. The control unit is adapted to carry out a diagnostic method to check operating conditions of one or more components of said electric poles. The diagnostic method includes the following steps: basing on a selected ideal position curve, obtaining one or more first curves indicative of an ideal behaviour of said switching apparatus, during an opening manoeuvre or closing manoeuvre of the switching apparatus; basing on detection signals provided by a closed-loop control arrangement of said control unit, calculating one or more second curves indicative of an actual behaviour of said switching apparatus, during an opening manoeuvre or closing manoeuvre of said switching apparatus; and carrying out a comparison procedure among said first and second curves.

Abstract: A method of performing a circuit-breaking and closing operation in a three-phase system having a first phase, a second phase lagging the first phase by 120°, and a third phase lagging the first phase by 240°, includes: a) opening only one of the first phase, the second phase and the third phase before a zero crossing of a current of the corresponding phase, b) opening the remaining phases of the first phase, the second phase and the third phase after step a), and c) closing the first phase, the second phase and the third phase simultaneously or essentially simultaneously at a phase to ground voltage of the phase of the first phase, the second phase and the third phase which lagging the phase that was opened in step a) by 120° in a time range from 60° before a peak of the phase to 90° after the peak.

Abstract: A switching apparatus for medium voltage electric systems, the switching apparatus including one or more electric poles, each electrically coupleable with a corresponding electric line, the switching apparatus including: for each electric pole, a fixed contact and a corresponding movable contact, the movable contact being reversibly movable, along a corresponding translational displacement axis, between a decoupled position from the fixed contact and a coupled position with the fixed contact; an actuation assembly having, for each electric pole, an actuation shaft rotating about a rotation axis during a closing manoeuvre or an opening manoeuvre of the switching apparatus; for each electric pole, a motion transmission assembly including an eccentric mechanism operatively coupled with the actuation shaft.

Abstract: A method of performing a circuit-breaking and closing operation in a three-phase system having a first phase, a second phase lagging the first phase by 120°, and a third phase lagging the first phase by 240°, includes: a) opening only one of the first phase, the second phase and the third phase before a zero crossing of a current of the corresponding phase, b) opening the remaining phases of the first phase, the second phase and the third phase after step a), and c) closing the first phase, the second phase and the third phase simultaneously or essentially simultaneously at a phase to ground voltage of the phase of the first phase, the second phase and the third phase which lagging the phase that was opened in step a) by 120° in a time range from 60° before a peak of the phase to 90° after the peak.

Abstract: The present invention relates to a method for controlling a motor-driven vacuum circuit breaker. The method comprises initiate opening (S100) the circuit breaker, wherein the circuit breaker moves with an average opening speed of a contact pair of the circuit breaker, from a closed position to an open position of the circuit breaker, and decelerating (S110) the opening speed of the contact pair to below the average opening speed before the open position is reached to avoid overshoot, and initiate closing (S120) the circuit breaker, wherein the circuit breaker moves with an average closing speed of the contact pair, from the open position to the closed position, and decelerating (S130) the closing speed of the contact pair to below the average closing speed before contact touch at the closed position, wherein the circuit breaker moves with the decelerated speed at contact touch. A motor-driven vacuum circuit breaker, a computer program and a computer program product are also presented.

Abstract: A method for controlling a circuit breaker, the circuit breaker is connected in a three-phase system having an inductive load, and the method includes a method for controlling a circuit breaker, the circuit breaker being connected in a three-phase system having an inductive load, the method includes opening a first phase of the three-phase system before a zero crossing of a current in the first phase, opening the second and third phases of the three-phase system a quarter period after opening the first phase, closing the first and second phase at a peak voltage of a voltage between the first and second phases, and closing the third phase a quarter period after closing the first and second phases. A circuit breaker controller is also presented.

Abstract: A method for controlling a circuit breaker, the circuit breaker is connected in a three-phase system having an inductive load, and the method includes a method for controlling a circuit breaker, the circuit breaker being connected in a three-phase system having an inductive load, the method includes opening a first phase of the three-phase system before a zero crossing of a current in the first phase, opening the second and third phases of the three-phase system a quarter period after opening the first phase, closing the first and second phase at a peak voltage of a voltage between the first and second phases, and closing the third phase a quarter period after closing the first and second phases. A circuit breaker controller is also presented.

Abstract: A switching apparatus for medium voltage electric systems, the switching apparatus including one or more electric poles, each electrically coupleable with a corresponding electric line, the switching apparatus including: for each electric pole, a fixed contact and a corresponding movable contact, the movable contact being reversibly movable, along a corresponding translational displacement axis, between a decoupled position from the fixed contact and a coupled position with the fixed contact; an actuation assembly having, for each electric pole, an actuation shaft rotating about a rotation axis during a closing manoeuvre or an opening manoeuvre of the switching apparatus; for each electric pole, a motion transmission assembly including an eccentric mechanism operatively coupled with the actuation shaft.

Abstract: An electric power distribution switchgear is connected between an electric power grid and an electric power equipment. The switchgear includes a synchronized vacuum switching apparatus configured to break the current to the electric power equipment using a synchronized technique to avoid re-ignition during the breaking and thus any transients caused by such re-ignition; and a surge arrester arrangement connected to the electric power equipment, the surge arrester arrangement being designed and configured to only handle transients caused by the current chopping at the breaking. The surge arrester arrangement can be arranged remote from the electric power equipment, such as e.g. in the same casing as the synchronized vacuum switching apparatus.

Abstract: An electric power distribution switchgear is connected between an electric power grid and an electric power equipment. The switchgear includes a synchronized vacuum switching apparatus configured to break the current to the electric power equipment using a synchronized technique to avoid re-ignition during the breaking and thus any transients caused by such re-ignition; and a surge arrester arrangement connected to the electric power equipment, the surge arrester arrangement being designed and configured to only handle transients caused by the current chopping at the breaking. The surge arrester arrangement can be arranged remote from the electric power equipment, such as e.g. in the same casing as the synchronized vacuum switching apparatus.

Abstract: An arc detector for detecting undesired arcs. The arc detector includes: an antenna for receiving an electromagnetic signal representing an arc; and a discriminator for analyzing a signal from the antenna, the discriminator including a spectrum analyzer arranged to detect whether the signal represents a normal arc or an undesired arc. The discriminator is arranged to detect whether the signal represents a normal arc or an undesired arc by comparing signal levels at frequencies of a spectrum of the signal corresponding to at least one partial reference spectrum, and determining the arc to be a normal arc if a deviation from the reference spectrum is less than a threshold deviation. A corresponding method is also presented.

Abstract: A device for switching in and out a load with respect to an alternating voltage feeder has two mechanical switches connected in series in a current path between the load and the feeder and each having a by-pass branch with at least one member with ability to block current therethrough in at least a blocking direction and conduct current therethrough in at least one direction. A unit is adapted to control a procedure of a switching out and switching in by synchronization with the current in the feeder and the voltage of the feeder, respectively.

Abstract: An arc detector for detecting undesired arcs. The arc detector includes: an antenna for receiving an electromagnetic signal representing an arc; and a discriminator for analysing a signal from the antenna, the discriminator including a spectrum analyser arranged to detect whether the signal represents a normal arc or an undesired arc. The discriminator is arranged to detect whether the signal represents a normal arc or an undesired arc by comparing signal levels at frequencies of a spectrum of the signal corresponding to at least one partial reference spectrum, and determining the arc to be a normal arc if a deviation from the reference spectrum is less than a threshold deviation. A corresponding method is also presented.