Abstract:
A land electrode for a high voltage direct current transmission system including a converter station with a grounding point. The land electrode is connected to the grounding point and includes a plurality of electrode sections. Each electrode section includes at least one electrode element.
Abstract:
The invention relates to a VSC-converter for converting direct voltage into auxiliary voltage and vice versa, which comprises a series connection of at least two current valves (5, 6) arranged between two poles (7, 8), a positive and a negative, of a direct voltage side of the converter, each current valve comprising several series connected circuits (12), each of which circuits comprising a semiconductor component (13) of turn-off type and a rectifying component (14) connected in anti-parallel therewith, an alternating voltage phase line (16) being connected to a midpoint (15), denominated phase output, of the series connection of current valves (5, 6) between two of said current valves while dividing the series connection into two equal parts. Each of the series connected circuits (12) of the respective current valve comprises, in order to make possible a good voltage distribution between the semiconductor components (13) of turn-off type included in the respective current valve, a snubber capacitor (17) connected in parallel with the semiconductor component (13) of turn-off type included in the circuit. The converter (1) further comprises a resonance circuit (18) for recharging the snubber capacitors (17) of the current valves.
Abstract:
A VSC-converter for converting direct voltage into alternating voltage and conversely has at least two phase legs (1-3) with each at least two current valves (4-9) connected in series, the valves consisting of at least a semiconductor element (10) of turn-off type and a rectifying member (11) connected in anti-parallel therewith. A midpoint (12) of the phase leg between said valves is adapted to form a phase output and be connected to a phase (29) of an alternating voltage network. The phase legs (1-3) of the converter are connected in series, and opposite ends of the series connection formed by an outer end of a respective outer phase leg (1-3) in the series connection are intended to be connected to a pole conductor (19, 20) each of a direct voltage network.
Abstract:
A plant for transmitting electric power comprises at least one VSC-converter (1). It comprises also at least one DC/DC-converter (33, 34) having two current valves connected in series and an inductance connected to a midpoint therebetween. The DC/DC-converter is through said inductance connected to a first of the poles of the direct voltage side of the converter and through a first output terminal connected to one of the current valves to the second of the poles so as to obtain an unbalanced step-up-transformation of the direct voltage between the two poles while obtaining a potential having a higher value on the second output terminal (27) of the DC/DC-converter connected to the second current valve than on said first output terminal (28).
Abstract:
A power transmission system for high-voltage direct current comprises a rectifier station (1) and an inverter station (2), which are interconnected by a dc connection (4), as well as a third converter station (3) connected between the dc connection and an ac network (3c). The third converter station comprises a converter (3a) connected to the dc connection via a direct-voltage converter (5). The direct-voltage converter comprises at least a first and a second converter stage (8:1, 8:2), each with a positive terminal (TP:1, TP:2), a negative terminal (TM:1, TM:2) and an output terminal (TO:1, TO:2) and comprising a voltage-source converter circuit (V, C1, SL) with at least one extinguishable semiconductor valve (T1, T2). The positive terminal of the second converter stage is connected to the output terminal of the first converter stage and the output terminal of the second converter stage is connected to the negative terminal of the first converter stage.
Abstract:
A power semiconductor valve device including an enclosure for semiconductor components and a hollow insulating body to supply power to the semiconductor components from a remote location, in which the hollow insulating body is formed from a non-ceramic material and includes concentrically mounted tubes spaced from each other to provide an annular gap between them.
Abstract:
A converter station for power transmission by means of high voltage direct current has an electrode line protective device for detection of ground faults on the electrode line of the station. An alternating voltage generator injects an alternating signal with a predetermined frequency on the electrode line. The two ends of the electrode line are provided with suppression filters tuned to the measuring frequency. The suppression filter arranged at the remote end of the electrode line is matched, by means of a resistor to the wave impedance of the electrode line. An impedance measuring device senses the impedance of the electrode line at the feeding point in relation to the ground at the measuring frequency. An indicating signal is delivered from the measuring device if the impedance measured deviates from the impedance of the electrode line when in a faultless state.
Abstract:
A detector arrangement related to a contact device in a system for driving an electrically propellable vehicle along a roadway. The system comprises a plurality of road sections subdividing the roadway, each one connected to one or more electric stations for charging a set of batteries of the vehicle and/or supplying the necessary power and energy for driving the vehicle forward.The contact device comprises displaceable current collectors disposed underneath the vehicle, which are moveable up and down and sideways. The current collectors are coordinated with control equipment to bring the current collector into mechanical and electrical contact with conducting rails arranged in a track in the roadway. The detector arrangement comprises one or more coils and is adapted to sense the variation of a magnetic field generated by additional electrical conductors disposed in the track.
Abstract:
A plant for transmitting electric power through HVDC includes two converter stations interconnected by a monopolar direct voltage network and each having an alternating voltage side for feeding electric power from one of said alternating voltage sides to the other. Each station has a line commutated converter. The plant is upgraded by making the direct voltage network bipolar, providing each station with a Voltage Source Converter and providing two switches for both line commutated converters or both Voltage Source Converters and a device configured to control said four switches.
Abstract:
A vehicle-related system adapted for electrically driving a vehicle along a road-way. The vehicle has three sources of power: a vehicle-related power generator, a set of batteries and vehicle-external electric stations. The vehicle is provided with a current collector which is displaceable up and down and sideways in relation to the direction of transportation, in order to be brought into mechanical and electrical contact with elongated tracks positioned below the roadway and comprising a conductor adapted to be connected with an electric station. A circuit, determining instantaneous power content of the set of batteries, is adapted to connect the vehicle-external power source via a switch belonging to the electric station, in order to charge the set of batteries and/or to supply power to the vehicle motor via a control circuit, when the power content of the set of batteries is at a predetermined level of power, lying below a maximum power content, and a supply of power or voltage from the vehicle-external power source is available.