Control apparatus for D.C. power transmission system

Abstract

This invention relates to an apparatus for controlling a D.C. power transmission system having a line-commutated converter which is connected between a first A.C. system and D.C. power transmission lines and which performs power conversion between A.C. power and D.C. power, and a forced-commutated converter which is connected between the D.C. power transmission lines and having a second A.C. system and which performs power conversion between A.C. power and D.C. power. In order to control transmission power in the two-terminal D.C. power transmission system wherein the two A.C. systems are associated by direct current, a control apparatus for a D.C. power transmission system according to this invention includes a voltage detector which detects a D.C. voltage of the D.C. power transmission lines, a first control circuit for comparing the output of the voltage detector with a voltage reference signal and for controlling ignition of the self-excited converter in accordance with the comparison, a detector which detects a current which is proportional to the conversion power of the line-commutated converter, and a second control circuit for comparing the output of the current detector with a power reference signal and for controlling ignition of the line-commutated converter in accordance with the comparison.

Dependencies are inferred from the claim text.