Patent ID: 6411066
Filing Date: 2002-06-25
Classification: H02J,H02M,Y02E

Abstract:
A high voltage direct current transmission system comprising:first and second converter stations coupled to each other via a direct current link, each converter station having a voltage source converter, the first converter station having first voltage sensing means for sensing a first direct voltage, and voltage control means for controlling the first direct voltage, the second converter station having active power control means for controlling an active power flow based on a reference value, wherein:the voltage control means controls the first direct voltage of the first converter station based on only a sensed instantaneous value of said first direct voltage and a first voltage reference value therefor, for a voltage control that is independent of a flow of active power through the first converter; the second converter station comprises second voltage sensing means for sensing a second direct voltage; the power control means of the second converter station comprises voltage control means for controlling the second direct voltage of the second converter station based on a sensed instantaneous value thereof and a second voltage reference value; and said second voltage reference value is formed based on a third voltage reference value and on a voltage reference correction signal formed based on a quantity indicative of the active power flow through the second converter station and the reference value therefor.