Abstract:
The invention concerns a converter as well as a cooling device and a method for cooling at least a first and a second group of electrically interconnected electrical components (SWA1, SWA2, SWA3, SWA4, SWA5, SWA6, SWA7, SWA8, SWB1, SWB2, SWB3, SWB4, SWB5, SWB6, SWB7, SWB8) in the converter, where the first and second groups are placed on opposite sides of a conductor leading to a connection terminal of the converter. The cooling device (22) comprises a first transporting arrangement (HSA1, HSA2, HSA3, HSA4, HSA5, HSA6, HSA7, HSA8, HSA9, COA1, COA2, COA3, COA4, COA5, COA6, COA7, COA8) transporting cooling medium (M) past the first group and a second transporting arrangement (HSB1, HSB2, HSB3, HSB4, HSB5, HSB6, HSB7, HSB8, HSB9, COB1, COB2, COB3, COB4, COB5, COB6, COB7, COB8) transporting the same cooling medium past the second group.
Abstract:
A method and an arrangement are provided for determining values of impedance parameters related to a transformer configuration including three single pole voltage transformers each respectively having at least a primary winding, a secondary winding and a tertiary winding. The primary windings are connected to phases of a three phase electric system. The arrangement is configured to conduct an earth fault in the three phase electric system, measure a primary voltage from the faulted phase, measure secondary voltages from the secondary windings, and determine values of one or more impedance parameters related to the transformer configuration on the basis of the measured primary voltage, the measured secondary voltages and an equation relating the primary voltage to the secondary voltages and the one or more impedance parameters.
Abstract:
A protection device for a power network performs a method to align measuring times of first and second measurements of an electric quantity, taken at different ends of a power network line transmitted with measuring times via a telecommunication network. In the method, a send transmission time from the local to remote end of the line and a receive transmission time from the remote to local end of the line are determined based on time signals from internal clocks. After a global time reference to synchronize the internal clocks is lost, a clock drift is determined between the internal clocks. The measuring times of the first and the second measurements are aligned using the send and receive transmission times as well as the clock drift. A sudden change in the clock drift is determined in order to recognize a route switching in the telecommunication network and the clock drift is corrected.
Abstract:
A method and an arrangement for voltage measurement with a transformer configuration comprising three single pole voltage transformers having tertiary windings open-delta connected with each other. The arrangement is configured to apply a correction to measured secondary voltages on the basis of one or more parameters of the voltage transformers and/or one or more quantities in a known relation to one or more parameters of the voltage transformers, one or more parameters of a circuit connected to the secondary windings and/or one or more quantities in a known relation to one or more parameters of the circuit connected to the secondary windings, and one or more parameters of a circuit connected to the tertiary windings and/or one or more quantities in a known relation to one or more parameters of the circuit connected to the tertiary windings.
Abstract:
A method and apparatus are provided for differential protection of a three phase electric connection of an electric system. The apparatus includes means for determining a value of an operate quantity, which operate quantity is based on a difference between current quantities at a first point and a second point of the electric connection, and means for detecting a fault in the electric connection between the first point and the second point if the value of the operate quantity exceeds a value of a predetermined threshold quantity. The operate quantity is based on a difference of residual currents at the first point and the second point, or a quantity indicative thereof, and a coefficient indicative of an angle between a residual voltage of the electric connection and the difference of residual currents at the first point and the second point.
Abstract:
A clip for connecting a conductor to a circuit interrupter in an electrical device is generally U-shaped and self-locking. The clip has a generally arcuate body and two generally linear legs. The legs extend vertically from the body. The legs have beveled edges that together with the generally arcuate body of the clip and a flat portion of the clip, allow an interlock to be formed between the clip and the conductor when the clip is in close contact with the conductor.
Abstract:
A conductor arrangement is provided for reducing very fast transients in high voltage applications. The conductor arrangement includes a conductor element having a main conducting orientation, and a conductive annular shell element coaxial to the conductor element, thus forming an annular cavity around the conductor element. The annular shell element in the main conducting orientation includes a first end portion and a second end portion. The first end portion is conductively connected to the conductor element. The second end portion includes an annular collar which is substantially coaxial to the conductor element, thus together with the conductor element forming a coaxial capacitor which has a solid material filling. The capacitor includes a surge arrester which may serve as an energy conversion portion.
Abstract:
A switch unit includes a current switching device drivable by an electromagnetic actuator for opening/closing an electric circuit associated with the switch unit, a first energy storage for storing electric energy for the electromagnetic actuator, and electronic controller means which are supplied by an external power line and control a supply of the electric energy from the energy storage means to the electromagnetic actuator. The switch unit includes emergency procedure operating means associated with the electronic controller means and provided with a second energy storage means. The emergency procedure operating means are configured for enabling driving of the current switching device and opening the associated electric circuit in an emergency condition in which a lack or drop or irregular supply of the external power line is experienced.
Abstract:
A high-voltage disconnector includes first and second contact elements movable along a disconnecting axis with first and second latching elements fixed thereto, respectively, a drive system for moving the first contact element in an opening direction along the axis to open the disconnector, and a restoring system for restoring the second contact element counter to the opening direction. With the disconnector closed, the first and second latching elements are arranged in a latched connection with one another. During an initial phase of the movement of the first contact element in the opening direction the latched connection initially remains, and the second contact element is carried along by the first contact element in the opening direction. During a disconnecting phase, the latched connection is released, the second element is restored by the restoring system counter to the opening direction, and the second contact element is disconnected from the first contact element.
Abstract:
A three-positions disconnector comprising, for each phase an insulating casing which comprises a first and a second cavity separated by an insulated partition wall, a through hole being present in said partition wall between said first and second cavity. The first cavity houses: a first fixed contact electrically connected to a corresponding branch conductor (of a bus-bar system; at least a portion of a movable contact pivotally mounted on a support positioned in the first cavity and electrically connected to a first electrical terminal positioned in said second cavity. The disconnector further comprises, for each phase, a second fixed contact suitable for ground connection. Also, the disconnector comprises an operating mechanism and a kinematical chain linking the movable contact with the operating mechanism; the movable contact is movable between a first position in which it is coupled to the first fixed contact, a second position in which it is isolated from both the first and second fixed contacts, and a third position in which it coupled to the second fixed contact.