Abstract: Simultaneous power and voltage control by a d-c-tie between a-c networks is carried out by means of fixed and switchable inductive and capacitive compensation elements including the tap changer of both converter transformers of a d-c-tie for setting the optimum operating point by a transformation ratio of the converter transformer taps matching the primary current ratio, of the converter transformer taps for the maximally permissible stage of the one converter transformer, taking into consideration control, extinction and overlap angles of the d-c-tie.

Abstract: A twelve pulse converter system is disclosed in which the two three-phase converter bridges forming the system are arranged one on top of the other in a single tower-like assembly and the valves of the bridges are disposed successively and separately as to phase. Additionally, the DC and AC terminals of one of the converter bridges are disposed on the one side of the tower-like assembly and the DC and AC terminals of the other of the converter bridges are disposed on the other side of the tower-like assembly, the DC terminals located on opposite sides being connected to each other by a DC lead.

Abstract: A converter valve which is constructed from modular elements is disclosed. Each of these modular elements comprises a group of thyristors arranged in side-by-side relationship and the drive means and circuit component group associated with such thyristor group. A metallic shield surrounds the thyristor group and its associated drive means and a portion of its associated component group. The shield, in turn, is supported within a metallic pressure tube which has both its ends closed off by bulkheads and is adapted to receive SF.sub.6 gas. The aforesaid bulkheads may be separate connecting members which, in addition, may also be designed as nodal elements and mechanical support points. The converter valve is constructed from a small number of the aforesaid modular elements, each element being replaceable without removing the gas from the entire valve.

Abstract: A gas-insulated thyristor arrangement with at least one thyristor column which is constructed of disk-type thyristors and is arranged, together with its associated drive and external-circuit modules, in a rotationally-symmetric shield which is fastened via at least one insulating standoff to the pressure tube of an electrically conductive pressure encapsulation. One end of the pressure tube is closed off by an end plate integrally formed therewith in the manner of a tank and the other end is closed off by means which includes at least one bulkhead of insulating material. The entire arrangement is filled with gaseous SF.sub.6 under pressure and detachable electrical connecting leads are extended through the bulkhead.

Abstract: A gas-insulated thyristor assembly is disclosed. The assembly comprises at least one thyristor column which includes disk-type thyristors which are arranged in side by side relationship. The assembly further includes drive and circuit component modules associated with the thyristors. In accordance with the invention, a rotationally-symmetric metallic shield surrounds the disk-type thyristors and is supported within a cylindrical metallic pressure tube by insulating posts. The opposite ends of the aforesaid pressure tube are closed off by bulkheads comprised of insulating material and the tube is adapted to receive SF.sub.6 gas under pressure. A detachable electrical connecting line is passed through each bulkhead and the pressure tube is adapted to be detachably connectable with adjoining pressure tubes.

Abstract: An improved filtering arrangement for a converter circuit in which a highpass filter, tuned to have a cutoff frequency which is less than the lowest harmonic to be filtered is provided instead of the customary plurality of filters tuned to individual harmonic currents. In a 12 pulse converter circuit, at least one highpass filter which is tuned to filter out harmonics starting with the fifth harmonic and which has a resonant frequency above the 11th harmonic is used.