Abstract: A substation has a converter comprising a first set (S1) of series connected converter valve elements provided between a first (V1) and a second (V2) potential, where the absolute value of the second potential is higher than the absolute value of the first potential, and a second set (S2) of converter valve elements, comprising at least one converter valve element, provided between the second and a third potential (V3), where the absolute value of the third potential is higher than the absolute value of the second potential and all converter valve elements of the second set are placed inside one or more casings (28) placed on elongated post-like insulation (24), where the potential of the end of the post-like insulation on which the casings are placed is in a range between the second and the third potential, while the other end of the post like insulation is at ground potential.

Abstract: A converter for converting alternating voltage into direct voltage and vice versa in a converter station of a high voltage transmission system. A series connection of converter valves includes power semiconductor devices connected in series and arranged in superimposed layers. The valves are arranged on top of each other in a column. Coolant liquid conducting tubes are in an extension over at least one part of the circumference of the column having no connections to cooling blocks for cooling the devices made of metal. Such metal tubes are arranged in the part for over this part of the column circumference forming an electric field shielding screen. The coolant liquid conducting tubes are when extending over parts of a circumference of the column where connections are made to cooling blocks made of an electrically insulating material. An electric field shield is arranged outside the column over these parts.

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 substation has a converter comprising a first set (S1) of series connected converter valve elements provided between a first (V1) and a second (V2) potential, where the absolute value of the second potential is higher than the absolute value of the first potential, and a second set (S2) of converter valve elements, comprising at least one converter valve element, provided between the second and a third potential (V3), where the absolute value of the third potential is higher than the absolute value of the second potential and all converter valve elements of the second set are placed inside one or more casings (28) placed on elongated post-like insulation (24), where the potential of the end of the post-like insulation on which the casings are placed is in a range between the second and the third potential, while the other end of the post like insulation is at ground potential.

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: An electrical apparatus, which is preferrably operated at voltages above 1 kV, comprises an electrostatic shield to reduce the electrical field strength outside of the apparatus. Advantageoulsy, the electrostatic shield is at least in part formed by a dielectric enclosure containing water.

Abstract: A converter for converting alternating voltage into direct voltage and vice versa in a converter station of a high voltage transmission system. A series connection of converter valves includes power semiconductor devices connected in series and arranged in superimposed layers. The valves are arranged on top of each other in a column. Coolant liquid conducting tubes are in an extension over at least one part of the circumference of the column having no connections to cooling blocks for cooling the devices made of metal. Such metal tubes are arranged in the part for over this part of the column circumference forming an electric field shielding screen. The coolant liquid conducting tubes are when extending over parts of a circumference of the column where connections are made to cooling blocks made of an electrically insulating material. An electric field shield is arranged outside the column over these parts.