Valve hall

The valves consist of thyristors, or at older plants, mercury arc rectifiers.

High voltage bushings are supported through the walls of the valve hall, to allow connections between the converter transformers on the one side and the DC switchyard on the other.

Because of high voltages, access to the valve halls is limited while the static inverter is running.

To protect communication systems from electromagnetic interference, valve hall buildings must have shielding installed to control emission of radio-frequency energy.

[2] At some HVDC converters such as at Cabora-Bassa, outdoor valves are installed in oil-immersed containers.