A 50-MW Thyristor Controlled Power Converter

In recent years, the use of thyristors for regulation of bulk power has grown appreciably. The Megaverter ® (Megawatt Power Converter) utilizes the thyristor for control and rectification to supply 52.5 MW of dc power for electrochemical use. The system consists of three Megaverters, each rated at 17.5 MW, connected in parallel. The thyristor assemblies are sized for worst-case short circuit surge, thereby providing maximum protection for critical components and eliminating costly downtime through nuisance tripping. Aluminum extrusion is used for the thyristor cabinet, allowing modular construction, reduction in size, and maximum design flexibility. Aluminum is also used for busbar and the thyristor water-cooled heatsink assemblies. The overall design approach results in simplified maintenance, reduced downtime, and simplicity of control for large thyristor controlled power converters.