Voltage control modified series-connected HVDC bridges using GTO thyristor by-pass valves

摘要

Direct current (DC) links are finding increasing use throughout the world in the form of the distance transmission and a synchronous interconnections. The objective of this paper is to present a new method to control the HVDC converter by modified series-connected bridges with GTO thyrisotr by-pass valves to give more reduction in both harmonics generation and reactive volt-ampere absorption for the rectifier and inverter modes of operation. Fast and continuous control of the DC voltage are possible using the proposed scheme, which uses by-pass GTO thyristor valves connected to tapping points on the secondary windings of the transformer for one bridge and the other one is operating as aconventional bridge.