Alternative solutions for thyristor control and gating for HVDC-valves

The next generation of thyristor valves for HVDC developed by ABB will be provided with an online diagnosis system. This is realised by further development of the thyristor control unit, TCU, using state of the art electronic circuits. Detailed information such as the status of the snubber circuit, thyristor temperature, etc., will be continuously available for each thyristor position. Each thyristor position has its own individual control, protection and monitoring, thus giving true redundancy for every component. With the diagnosis system, the intervals between scheduled maintenance measures can be increased. The diagnosis system will also give accurate information on the overload capability of the converter in real conditions.