HIGH VOLTAGE DIRECT CURRENT TRANSMISSION SYSTEM

摘要

A high voltage direct current transmission includes a rectifier station and an inverter station connected by a DC line. The rectifier station has uncontrolled valves and an arrangement enabling current control to be effective at over-current conditions for controlling the alternating voltage connected to the valves. There are first and second control circuits, the first of which is controlled in dependence on the line voltage and the second in dependence on the line current. A circuit for selecting either the first or the second control circuit is provided between the control circuits and the voltage control arrangement. The valves of the rectifier station may be arranged in two six-pulse groups mutually offset in phase, so reactively connected that they have the commutating reactance partly in common.