Abstract: An arrangement for interrupting current comprises a first and a second terminal. First, second, and third parallel circuit branches are arranged between the terminals to electrically connect two power networks. The first parallel circuit branch comprises a mechanical main circuit breaker, the second parallel circuit branch comprises an energy absorbing device, and the third parallel circuit branch comprises a resonant circuit and a voltage control means arranged in series. The voltage control means is controllable to inject energy into the resonant circuit to force a rapid increase of alternating current, wherein the alternating current flows in a loop containing the first and the third parallel circuit branches as the mechanical main circuit breaker is controlled to open to interrupt main current. Zero cross-over of the current through the mechanical main circuit breaker is thereby realized as the alternating current amplitude exceeds the main current amplitude.

Abstract: A circuit breaker comprises a switch and an actuator comprising a displaceable shaft mechanically connected to a movable contact in the switch. A Thomson coil is adapted to displace the shaft in a first direction, and a disconnecting device is connected in series with the switch and that is adapted to open during an interval when current is extinguished. An energy storage is provided being a separate part from the shaft and being adapted to store energy when the shaft moves in the first direction and to release energy to displace the shaft in a second direction, comprising a mass-spring arrangement with a body, a first spring between the shaft and one end portion of the body at a side facing the shaft and a second spring at a first end portion connected to a side of the body facing from the shaft and at second end portion being fixed. The movement of the body continues undisturbed to achieve a time interval wherein a current is extinguished.

Abstract: An arrangement for interrupting current comprising a first and a second terminal adapted to electrically connect two sections of a power system is provided. A voltage control means is controllable in use to inject energy into said loop to force a rapid increase of an alternating current flowing through said main branch while being controlled to open to interrupt a main current, and whereby zero cross-over of the current through the mechanical main circuit breaker is realized as the amplitude of the alternating current exceeds the amplitude of the main current. An energy absorbing device is adapted to limit the voltage across said capacitor and said mechanical breaker when the mechanical breaker is open, and across an inductive element if the voltage across the mechanical breaker breaks down, at or immediately after an opening process, thereby limiting the rate-of-rise and the peak of the current through said loop.

Abstract: A circuit breaker comprises a switch and an actuator comprising a displaceable shaft mechanically connected to a movable contact in the switch. A Thomson coil is adapted to displace the shaft in a first direction, and a disconnecting device is connected in series with the switch and that is adapted to open during an interval when current is extinguished. An energy storage is provided being a separate part from the shaft and being adapted to store energy when the shaft moves in the first direction and to release energy to displace the shaft in a second direction, comprising a mass-spring arrangement with a body, a first spring between the shaft and one end portion of the body at a side facing the shaft and a second spring at a first end portion connected to a side of the body facing from the shaft and at second end portion being fixed. The movement of the body continues undisturbed to achieve a time interval wherein a current is extinguished.

Abstract: An arrangement for interrupting current comprising a first and a second terminal adapted to electrically connect two sections of a power system is provided. A voltage control means is controllable in use to inject energy into said loop to force a rapid increase of an alternating current flowing through said main branch while being controlled to open to interrupt a main current, and whereby zero cross-over of the current through the mechanical main circuit breaker is realized as the amplitude of the alternating current exceeds the amplitude of the main current. An energy absorbing device is adapted to limit the voltage across said capacitor and said mechanical breaker when the mechanical breaker is open, and across an inductive element if the voltage across the mechanical breaker breaks down, at or immediately after an opening process, thereby limiting the rate-of-rise and the peak of the current through said loop.

Abstract: An arrangement for interrupting current comprises a first and a second terminal. First, second, and third parallel circuit branches are arranged between the terminals to electrically connect two power networks. The first parallel circuit branch comprises a mechanical main circuit breaker, the second parallel circuit branch comprises an energy absorbing device, and the third parallel circuit branch comprises a resonant circuit and a voltage control means arranged in series. The voltage control means is controllable to inject energy into the resonant circuit to force a rapid increase of alternating current, wherein the alternating current flows in a loop containing the first and the third parallel circuit branches as the mechanical main circuit breaker is controlled to open to interrupt main current. Zero cross-over of the current through the mechanical main circuit breaker is thereby realized as the alternating current amplitude exceeds the main current amplitude.

Abstract: A photovoltaic system for generating an output voltage that is uninfluenced by varying irradiation, includes a photovoltaic source having an input terminal and an output terminal. The photovoltaic system includes a voltage adding arrangement having a first input terminal and an output terminal. The voltage adding arrangement is connected in series with the photovoltaic source, and includes a first route having a voltage source and a second route as a voltage source bypass. The first and second routes extend between the first input terminal and the output terminal of the voltage adding arrangement. The first and second routes being alternately activateable.

Abstract: A power compensator for an electric power transmission line. The power compensator includes a voltage source converter, a capacitor and an energy storage device. The energy storage device includes a high voltage battery having a short circuit failure mode, a first main switch and second main switch for disconnecting the battery from the capacitor, and a control unit for operating the first and second switch.

Abstract: A photovoltaic system for generating an output voltage that is uninfluenced by varying irradiation, includes a photovoltaic source having an input terminal and an output terminal. The photovoltaic system includes a voltage adding arrangement having a first input terminal and an output terminal. The voltage adding arrangement is connected in series with the photovoltaic source, and includes a first route having a voltage source and a second route as a voltage source bypass. The first and second routes extend between the first input terminal and the output terminal of the voltage adding arrangement. The first and second routes being alternately activateable.

Abstract: An energy supply system adapted for supplying energy to equipment on a high voltage platform. The system includes a fuel cell and an effectuating capacitor. The system also includes an intermediate storage and supply unit. This unit stores energy from the fuel cell and supplies energy to the effectuating capacitor via an electric transforming unit. A high voltage platform including the energy supply system. An electrical network including the platform. A method for supplying energy to equipment on a high voltage platform.

Abstract: A method for controlling the power flow in an ac transmission line including prompt handling of voltage recovery and only thereafter thermal constraints.

Abstract: An apparatus for reducing subsynchronous resonance phenomena in a power transmission system. A determining arrangement determines components of the voltage from stator windings of a generator with one or more discrete frequencies. A calculating arrangement calculates, on a basis of the result of the determining, a voltage to be added to the voltage from the stator windings for reducing phenomena in the power system and an arrangement adapted to add the voltage calculated to the voltage from the stator windings.

Abstract: A temperature controller for providing heat to an energy storage device of a power compensator. The energy storage device includes a plurality of high temperature battery units on high potential. The temperature controller includes a pipe network for housing a heat transfer medium. The pipe network includes a main pipe loop and a local pipe loop in each battery unit. Each local pipe loop includes a first end for receiving a heat transfer medium and a second end for exhausting the medium.

Abstract: A power compensator for an electric power transmission line. The power compensator includes a voltage source converter, a capacitor and an energy storage device. The energy storage device includes a high voltage battery having a short circuit failure mode, a first main switch and second main switch for disconnecting the battery from the capacitor, and a control unit for operating the first and second switch.

Abstract: A charge controller of a high temperature battery for a power compensator of an electric power transmission line. The charge controller includes a sensor and a processor including a memory module. The charge controller includes a virtual battery model of the battery.

Abstract: An auxiliary power supply equipment for a high voltage installation includes a power source at ground potential, a load circuit at high potential, and a transmission link for coupling the power source to the load circuit. The power source includes a high frequency voltage generator, and the transmission link comprises a first and a second current path. Each path is closed by capacitive coupling to provide insulation between the ground potential and the high potential, and each current path has a reactive compensation means for series compensation of reactive power generated by the capacitive coupling.

Abstract: An electric network for generation and transmission of electric power, including a power generating part, a point of common connection for the power generating part, a transmission link, a load network, and a reactive power compensator. The transmission link is coupled between the point of common connection and a grid connection point at the load network. The reactive power compensator is coupled to transmission link. The power generating part includes at least one wind turbine with an electric generator of induction type, coupled to the point of common connection. The reactive power compensator includes a capacitor bank and in parallel coupling to the capacitor bank a controllable inductor having a magnetic core, a main winding for alternating current, and a DC-control winding for direct current. The DC-control winding for control of the magnetic flux is set up by the main winding via orthogonal magnetization of the core.

Abstract: A device for control of a compensator connected to a polyphase electric transmission network for reactive electric power in dependence on a voltage sensed in the transmission network. A voltage controller, in dependence on the difference of a reference value for the voltage and its sensed value, forms a reference value for a reactive power flow through the compensator. A transformation element represents the sensed voltage as a voltage vector in a rotating two-phase system of coordinates and forms a compensation signal in dependence on a sensed change of the angular position of the voltage vector in the two-phase system of coordinates. A summation element forms the reference value for reactive power flow through the compensator in dependence on the compensation signal.