Recovery of HVDC Interconnectors from Disturbances in the Thyristor Bridge

Use is made of a dynamic simulation programme to investigate the behaviour of HVDC inferconn` ctors during internal and external disturbances resulting in maloperation of the thyristor units. A comparison is made between conventional and newly proposed protective controls for their ability to regain normal operation. Special emphasis is given to invertor bridges connected to relatively small ac systems. An assessment is made of the severity of different types of convertor disturbances which is considered to be of relevance to the design and rating of thyristor-based convertor plant.