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The development of thyristor valves for HVDC began in the late 1960s. The first complete HVDC scheme based on thyristor was the Eel River scheme in Canada, which was built by General Electric and went into service in 1972. [17] Since 1977, new HVDC systems have used solid-state devices, in most cases thyristors. Like mercury arc valves ...
The thyristor valve was first used in HVDC systems in 1972 on the Eel River Converter Station in Canada. [23] The thyristor is a solid-state semiconductor device similar to the diode, but with an extra control terminal that is used to switch the device on at a
A valve hall is a building which contains the valves of the static inverters of a high-voltage direct current plant. The valves consist of thyristors, or at older plants, mercury arc rectifiers. Mercury arc rectifiers are usually supported by insulators mounted on the floor, while thyristor valves may be either supported by insulators or hung ...
The converter is usually installed in a building called the valve hall. Early HVDC systems used mercury-arc valves, but since the mid-1970s, solid state devices such as thyristors have been used. Converters using thyristors or mercury-arc valves are known as line commutated converters. In thyristor-based converters, many thyristors are ...
The thyristors, supplied by the German HVDC consortium (Siemens, AEG and Brown Boveri) used water cooling [10] for the first time in an HVDC project. Until that time, the relatively few HVDC schemes using thyristors had used either air cooling or, as on the Cahora Bassa project supplied by the same consortium, oil-cooling.
A thyristor (/ θ aɪ ˈ r ɪ s t ər /, from a combination of Greek language θύρα, meaning "door" or "valve", and transistor [1]) is a solid-state semiconductor device which can be thought of as being a highly robust and switchable diode, allowing the passage of current in one direction but not the other, often under control of a gate electrode, that is used in high power applications ...
In common with the valves at the Fulong station, the valves use 8.5 kV rated, 150 mm diameter electrically triggered thyristors. At Fengxia, each valve consists of 56 series connected thyristor levels (of which two are redundant), arranged in 8 thyristor modules of 7 thyristor levels each.
A back-to-back station has no transmission line and joins two separate AC grids at a single point. Historical HVDC systems used the Thury system of motor-generators but these have all been made obsolete by later developments such as mercury-arc valves (now also obsolete), thyristors, and IGBT power transistors.