METHOD AND DEVICE FOR SUPPRESSING RESONANTS IN THE INVERTER-SIDED AC VOLTAGE NETWORK OF A HIGH VOLTAGE DC CURRENT TRANSMISSION SYSTEM

摘要

If in a high-voltage d-c transmission system (HVDCTS), a resonance frequency of an a-c voltage network (NB) connected to the inverter (1B) is located in the vicinity of a voltage component contained in the a-c voltage network, a resonance frequency which often cannot be compensated by a current regulator controlling the rectifier stage (1A) is coupled into the d-c circuit of the HVDCTS via the inverter. Therefore, resonance phenomena which requires an emergency shutdown of the HVDCTS are generated. Therefore, a pilot quantity (U'd) is formed with a defined phase shift relative to the resonance oscillation of the HVDCTS voltage and added to the output of the current regulator. Thereby, a constant HVDCTS current can be generated for a given operating point and the resonance in the a-c voltage network (NB) can be damped. If the resonance oscillation is determined by two quantities (U'd, i'd) of, respectively, the HVDCTS voltage as well as of the HVDCTS current, stable damping of the resonance phenomena can be achieved by the pilot control described with the two quantities even for deviating operating points.