Patent ID: 8081497
Filing Date: 2011-12-20
Classification: H02H,H02J,Y02E

Abstract:
1. A converter station for connecting an AC system to a bipolar HVDC transmission line, said converter station comprising: two converters each having a DC-side thereof connected to a respective one of two poles of said transmission line on high potential and to a neutral bus for that pole of a DC neutral arrangement in common to the converters on zero potential by being earthed, and having an AC-side connected to said AC system, said DC neutral arrangement having a member connecting to two electrode lines and the arrangement being provided with first DC breakers enabling breaking of a first current path from the neutral bus of one pole to the neutral bus of the other pole at bipolar operation of the station for changing to monopolar operation thereof, a control device adapted to control a said changing from bipolar to monopolar operation by controlling a first DC breaker to open said current path between said two neutral buses and establish a current path to said electrode line connecting member for diverting the current from said one pole thereto, wherein said neutral arrangement is provided with two connecting members, one for each electrode line and a connector configured to connect each neutral bus to an optional of said two electrode line connecting members.