Transient of modified HVDC converters

摘要

The bridge circuit used in high voltage direct current (HVDC) converters may be modified by including by-pass thyristor valves connected to tapping points on the secondary windings of the transformer to give a reduction in both harmonic generation and reactive volt-ampere absorption for the rectifier and inverter modes of operation.rnIn this paper, control strategies for the transient response of the HVDC converter with either thyristor or GTO thyristor by-pass valves are investigated using several types of firing angle control logic. Fast and continuous control of the DC voltage is possible using the proposed scheme without the conventional on load tap-changer on the converter transformer. Experimental results on a laboratory model compare well with the predicted values.